WO2024079142A1 - Cut rolled expanded stem production - Google Patents

Abstract

The present invention relates to a method of treating shredded tobacco stems, comprising: (a) providing moisturized shredded tobacco stems; (b) expanding the shredded tobacco stems in a first expansion step; (c) further expanding the shredded tobacco stems in a second expansion step, wherein the shredded tobacco stems have a moisture content after the second expansion step which is greater than or equal to the moisture content after the first expansion step, wherein the moisture content is measured in oven volatiles (OV).

Description

Cut rolled expanded stem production

Technical field

The present invention relates to a method of treating shredded stem tobacco material to provide expanded shredded stem tobacco material. The invention further relates to an apparatus configured to perform a method of treating shredded stem tobacco material. The invention also relates to a tobacco product, such as an expanded shredded stem tobacco product.

Technical background

Smokable consumer goods, such as cigarettes or equivalents thereof, are enjoying growing popularity worldwide. Such consumer goods can provide for certain stimuli when smoked and or inhaled by a user.

Smokable consumer goods usually comprise smokable material with tobacco stems. The stem is a relatively woody part of the tobacco leaves and provides for structural rigidity of the smokable consumer good. The stems can make up as much as 20 to 30% by weight of the tobacco leaves. They generally contain lower levels of alkaloids and other nitrogenous compounds, but higher levels of cellulose. Upon combustion, stems generate smoke that is inferior compared to other parts of the leaf. However, to improve yield, cut tobacco stem may be included with cut lamina in smokeable material for smoking articles such as cigarettes.

The stems are usually subjected to one or more treatment procedures in order to improve the taste and burning characteristics of the smokable material. Such treatment includes, for instance, expansion. A particular treatment process is the cut rolled expanded stem (CRES) production. In such a production process, tobacco leaf stems are rolled, flattened and shredded. Furthermore, they are expanded, for instance by being soaked in water and rapidly heated and then dried.

Such a production process poses several challenges. For instance, the production process should increase the filling capacity, also referred to as fill value (measured in unit volume per unit weight) of the tobacco stem. This should not adversely affect sensorial characteristics of the smokable consumable. Increasing the fill value bears the potential to reduce the net tobacco weight (NTW, i.e. the weight of the tobacco in tobacco-rod). In addition, the quality of the smokable consumable should be improved, e.g. a tobacco rod hardness should be increased and/ or loose ends should be reduced.

Traditional production processes known in the prior art fail to cope with these challenges or fail to meet these challenges to a satisfactory extent. Furthermore, existing processes limit water penetration to non-cut tobacco stem. In addition, water penetration of the tobacco stem is not achieved to a reasonable degree. Traditional production processes are also subject to variations in the final smokable consumable, which is uneconomical and disadvantageous.

Therefore, it is desirable to provide an improved production process for cut rolled expanded stems.

Against this background, an object of the present invention is to overcome the deficiencies of the prior art and to address one or more or all of the above-mentioned challenges. Particularly, it is an object of the present invention to develop and/or implement an improved process of cut rolled expanded stem production. An enhanced, i.e. a higher fill value of tobacco material should be reached. It is a further object to develop and/or implement such an improved process whilst ensuring high sensorial characteristics. In addition, it is an object to reduce costs of the smokable consumer product. It is generally an object to provide an improved production process that is economical, ecological and cost-effective.

These and other objects, which become apparent from the following description, are solved by the subject-matter of the independent claims. Preferred embodiments are subject of the dependent claims, and the skilled person finds hints for other suitable embodiments of the present invention throughout the disclosure of the present application.

Summary of the invention

Definitions

The term “tobacco stems” as used herein includes stems and veins of tobacco leaves. The term may also be referred to as tobacco material.

The term “fill value” may be the volume occupied by a given weight or mass of the material. The terms “filling value”, “fill capacity” and “filling capacity” maybe used synonymously to the term “fill value”. In some instances, the term may also be referred to as “filling power”. An increased fill value of a tobacco material entails a lower weight of the material required to fill a volume, such as a tobacco rod of a cigarette. In particular, a high fill value could indicate that a lower weight of tobacco may be required to produce a cigarette rod of defined dimensions than required with tobacco of lower fill value. The fill value maybe increased by stiffening tobacco, expanding tobacco and/ or by increasing surface roughness of the tobacco. The fill value of a tobacco material may be determined in terms of the “Corrected Cylinder Volume” (CCV). The CCV is the cylinder volume (CV) of the tobacco material at a normalized moisture content of a certain amount of oven volatiles (OV, as detailed below). The CV may be the volume that a given weight of tobacco occupies under a defined pressure. As an example, the cylinder volume (CV) may be determined using standard methods, such as a Mettler Toledo densimeter DE61 type fitted with a measuring head for cut tobacco and a tobacco cylinder container. The fill value of tobacco material expressed as a CCV value is the fill value of tobacco material, measured at any moisture content (OV), e.g. other than normalized conditions, which is corrected to normalized conditions.

As used herein, the “moisture content” maybe determined and/or measured in “oven volatiles” (OV).

The “moisture content” is a key parameter in the tobacco industry. It may have a great impact on tobacco materials, the corresponding properties and/or the final product. For instance, the moisture content may have an impact on structure, texture, viscosity, fluidity, density, flavour purity, concentration, conductivity, grading of tobacco leaves or similar properties of the material. It is common for “moisture” or “moisture content” to be used to refer to the water content of a material, but in the technical field of tobacco, one usually differentiates between “moisture” as water content and “moisture” as oven volatiles. Water content maybe defined as the percentage of water contained in the total mass of a solid substance. Volatiles maybe defined as the percentage of volatile components contained in the total mass of a solid substance. This may include water and other volatile compounds. Oven dry mass is the mass that remains after the volatile substances have been removed, e.g. by heating. It is expressed as a percentage of the total mass. Accordingly, oven volatiles (OV) are the mass of volatile substances that were driven off. Typically, the term oven volatiles % is used.

The moisture content (oven volatiles) may be measured for instance according to the “Coresta recommended method”, e.g. in a version 3 of December 2021. In particular, it may be measured as the reduction in mass when a sample, such as a tobacco sample, is dried in a forced draft oven at a temperature regulated to no°C ± i°C for three hours ± 0.5 minutes. After drying, the sample is cooled in a desiccator to room temperature for approximately 30 minutes. This may allow the sample to cool and may prevent thermal draughts affecting the stability of the measurement. It may be the case that, on an absolute basis, the results of moisture content determination by oven drying are greater than the results of water content analysis, e.g. when using a specific method such as ISO 6488 (Karl Fischer method). The difference maybe sample-type dependent and may be due to the loss of volatile materials, other than water, from tobacco and tobacco products during oven drying. It is possible that the difference is small, in case a low number of volatiles is present that are not accountable to water.

As an illustrating example, the percentage moisture content (oven volatiles) can be calculated using following equation:

In this equation, M is the moisture content. Wjs the initial weight of the tobacco sample, including tin and lid. W₂is the weight of the dry tobacco sample after testing, including tin and lid. W_T is the tare weight of tin and lid. Different measurement methods for the moisture content (oven volatiles) are possible. Examples are the hearson oven method, the 3h/82°C -oven method, the 100 min/i03°C -oven method, and the 30 min/io6°C -oven method. Different oven types may also be used for these tests, e.g. a binder oven, a rotary oven, or an electric air blast oven.

In the following, unless stated otherwise, references to moisture content should be considered to be references to moisture content measured in oven volatiles (OV).

The term “percentage points”, “percentage point” and/or “percent point” as used herein maybe understood as a unit for a difference between two percentages. E.g. the term is used when comparing two different percentages. For instance, the difference between 20 percent and 30 percent is 10 percentage points (it may not be 10 percent).

General aspects of the invention

A 1st embodiment of the invention is directed to a method of treating shredded tobacco stems, comprising:

(a) providing moisturized shredded tobacco stems;

(b) expanding the shredded tobacco stems in a first expansion step;

(c) further expanding the shredded tobacco stems in a second expansion step, wherein the shredded tobacco stems have a moisture content directly after the second expansion step which is greater than or equal to the moisture content after the first expansion step, wherein the moisture content is measured in oven volatiles (OV).

Shredded tobacco stems may be understood as tobacco stems which are at least partially processed. E.g., the stems maybe cut or otherwise made into smaller pieces. Any suitable type, style and/ or variety of tobacco may be used herein. The tobacco may be cased or uncased. Suitable examples of tobacco which could be used include in a non-exhaustive list Virginia, Burley, Oriental, (Galpao) Comum, Amarelinho and Maiyland tobaccos, and blends of any of these types. It may be realizable that tobacco stems are threshed to be separated from lamina or leaf lamina.

Step (a)

Moisturized shredded tobacco stems are provided in step (a). This means that such moisturized shredded tobacco stems should at least be made available. Preferably, the tobacco stems should not be fully or completely dry. Thus, the tobacco stems may be at least partially moisturized. As an example, the stems may already be (slightly) moisturized when harvested. In another example, the stems could be soaked in liquid before being flattened and then cut.

An increased moisture content may be beneficial for the subsequent processing. Thus, preferably, the moisture content of the provided moisturized tobacco stems should be between about 30% and about 40% OV. Most preferably, the provided moisturized shredded tobacco stems have a moisture content of 36% OV.

In some embodiments, step a) additionally comprises one or more some sub-steps as detailed below. As an example, these one or more sub-steps may be separate steps, such that they do not form part of step a). The sub-steps may comprise a step of delivering and/or obtaining tobacco stems (at), soaking the tobacco stems in water (a2), flattening the tobacco stems (as) and/or cutting the tobacco stems (aq). It is possible that steps (at) to (aq) are performed in the mentioned order. Cutting the tobacco stems (aq) may comprise cutting the stems to sizes of about less than 1 mm, preferably less than 0.8 mm, more preferably less than 0.5 mm, most preferably less than 0.3 mm. An optional aging and/ or cooling step may also be performed as further detailed below.

Step (b)

Expanding the shredded tobacco stems means that the fill value of the shredded tobacco stems is at least partially increased. This may be understood such that the volume occupied by the material is increased. Thus, a density may be reduced.

As an example, the fill value of the shredded tobacco stems after expanding the shredded tobacco stems in the first expansion step maybe at least 2%, preferably at least 5%, more preferably at least 10%, most preferably at least 15% (or even higher) greater than the fill value of the shredded tobacco stems before expanding the shredded tobacco stems in the first expansion step. For instance, the fill value may be about 450- 550 ml/100 g, i.e. 450-550 cc/100 g or q.5-5-5 ml/g before expanding the shredded tobacco stems in the first expansion step. After expanding the shredded tobacco stems in the first expansion step, the fill value may be about 550-750 ml/ too g, i.e. 550- 750 cc/ too g or 5-5-7.5 ml/g. As explained above, the fill value should be measured at a certain normalized or targeted moisture content. As an example, such normalized moisture content may be 12.5% oven volatiles (OV). The fill value may be slightly different if other normalized moisture content values are applied.

Expanding the shredded tobacco stems in the first expansion step may comprise subjecting the shredded tobacco stems to steam. This may comprise applying steam by using a heating tunnel, an STS (Steam Treated Stem) unit or generally a steam jet under pressure or anything similar. The working principle of such an expansion maybe illustrated as follows. The shredded tobacco stems maybe subjected to steam under pressure, i.e. steam injection. Subsequently, the pressure maybe released, causing the gas to expand and the tobacco cells to increase in volume. Thereby, the treated tobacco stems may have an increased volume (this influences the fill value).

Expanding may also be achieved by way of a liquid, e.g. an organic liquid. For instance, carbon dioxide maybe subjected to the tobacco stems, followed by warming or heating leading to carbon dioxide gas. Preferably, the shredded tobacco stems are expanded by exposure to steam. Such an expansion is beneficial, since water penetration to shredded stems is increased.

During expansion of the shredded tobacco stems in the first expansion step, it may be feasible that a moisture content (OV) of the shredded tobacco stems at least remains the same as before the first expansion step. As an example, the moisture content (OV) may be about 1 to 5 percentage points, preferably 1 to 2 percentage points greater after the first expansion step compared to before the first expansion step. A moisture content (OV) greater by 2 percentage points may be understood such that the moisture content (OV) increases from about 36% (prior to the first expansion step) to 38% (after the first expansion step).

As detailed further below, an aging and/ or cooling method step may be applied.

Preferably, such an optional aging and/ or cooling method step may be applied after the first expansion step, preferably directly after the first expansion step.

Step (c) The shredded tobacco stems are further expanded in a second expansion step, which follows the first expansion step. In one example, the second expansion step directly follows the first expansion step. However, further method steps maybe comprised in between.

In the second expansion step, a similar mechanism of expansion may be applied as in the first expansion step. Therefore, expanding the shredded tobacco stems in the second expansion step may comprise subjecting the shredded tobacco stems to steam. This may comprise applying steam by using a heating tunnel, an STS (Steam Treated Stem) unit or generally a steam jet under pressure. The expansion of the shredded tobacco stems in the second expansion step may be performed in the same or an additional unit as the expansion of the shredded tobacco stems in the first expansion step.

During further expansion of the shredded tobacco stems in the second expansion step, a moisture content (OV) of the shredded tobacco stems at least remains the same as before the second expansion step. As an example, the moisture content (OV) may be about i to 5 percentage points, preferably i to 2 percentage points greater after the second expansion step compared to before the second expansion step. A moisture content (OV) being greater by i percentage point may be understood such that the moisture content (OV) increases from about 38% (prior to the second expansion step) to 39% (after the second expansion step).

The fill value of the shredded tobacco stems after expanding the shredded tobacco stems in the second expansion step maybe at least 20%, preferably at least 30%, more preferably at least 35%, most preferably at least 40% greater than the fill value of the shredded tobacco stems before expanding the shredded tobacco stems in the first expansion step, i.e. the fill value of the untreated shredded tobacco stems. As an example, the fill value maybe about 450-550 ml/100 g, i.e. 450-550 cc/100 g or 4.5- 5.5 ml/g before expanding the shredded tobacco stems in the first expansion step and/or before treating the shredded tobacco stems; after expanding the shredded tobacco stems in the second expansion step, the fill value may be about 750- 850 ml/100 g, i.e. 750-850 cc/100 g or 7.5-8.5 ml/g. The fill value should be measured at a certain normalized or targeted moisture content. As an example, such normalized moisture content maybe 12.5% oven volatiles (OV). The fill value maybe slightly different if any other normalized moisture content values are applied.

By way of the first and the second expansion step, the shredded tobacco stems may be fully expanded, i.e. the fill value of the shredded tobacco stems may have reached an optimum level after, e.g. directly after, the second expansion step. Thus, there may no further substantial expansion necessary or required.

An increased fill value is appreciated since it results in less tobacco per volume of a final product. In other words, an increased fill value leads to a lower weight of material being required to fill a tobacco rod. Thus, the net tobacco weight (NTW) may be reduced. This reduces costs of the final product. Further, the same rod hardness may be maintained, which ensures sufficient rigidity. It may also be possible that a filter length is reduced if the NTW is maintained so as to achieve the same overall pressure drop of the smoking article. Another advantage of an increased fill value is that it can be used for quality improvement of a final product. As an example, a tobacco rod hardness could be increased. Additionally, loose ends of a tobacco rod may be reduced. Thus, the overall integrity, mechanical stability and rigidity of the final product can be improved. This is appreciated by the user getting in contact with such a final product.

It is also appreciated that the shredded tobacco stems have a moisture content (OV) after the second expansion step which is greater than or equal to the moisture content after the first expansion step. This maybe understood in such a way that the moisture content measured directly after the second expansion step or at the end of the second expansion step is greater than or equal to the moisture content after the first expansion step. The inventors found that expansion can be performed more efficiently in this manner, since the moisture content promotes and facilitates expansion. Additionally, the proposed method ensures a predictable, reproducible and reliable quality of the final product as compared to conventional methods, which oftentimes lead to large variations of the product.

The increased fill value reached or achieved after the second expansion step, e.g. directly after the second expansion step (in some cases this may be at the end of the second expansion step) may also be applicable to the final product, i.e. the tobacco product. This is beneficial for the final product, since it can benefit from the advantageous effects associated with the increased fill value of the shredded tobacco stems. Thus, it maybe appreciated that no substantial loss in the fill value after the second expansion step occurs. As an example, in case there is one or more further processing steps after the second expansion step, such as a drying and/or cooling step, no substantial loss in the fill value of the shredded tobacco stems may occur. Thus, the fill value advantageously increased for the expanded shredded tobacco stems may readily be recognized in the final product.

According to a 2nd embodiment, in the preceding embodiment, the shredded tobacco stems are kept at a moisture content of at least io% OV, preferably at least 20% OV, most preferably at least 30% OV during the second expansion step, preferably during the first and second expansion steps, most preferably during and between the first and second expansion steps; and/or the shredded tobacco stems are kept at a moisture content of at most 50% OV, preferably at most 45% OV, most preferably at most 40% OV during the second expansion step, preferably during the first and second expansion steps, most preferably during and between the first and second expansion steps.

Keeping the shredded tobacco stems at least at a specified moisture content means that such a specified moisture content is at least substantially maintained. In other words, the moisture content could be higher but should at least meet the specified minimum moisture content. Similar considerations may apply vice versa to the upper bound of the moisture content. As an example, during the second expansion step, the moisture content should be kept preferably at at least 20% OV and/or at at most 40%. Thereby, if the second expansion step starts at a moisture level of about 30% OV, the moisture content should not become lower than 30% OV. However, the moisture content could become higher than 30% OV (up to 40% OV) during the second expansion step.

The term “during” the first/second expansion step includes the time frame from the beginning to the end of the first/second expansion step, respectively.

Most preferably, the specified moisture content values are kept during and between the first and the second expansion steps. Thus, in case there are further processing steps between the first and the second expansion step, there maybe no substantial change of the moisture content measured in oven volatiles (OV). As used herein, “no substantial change” may encompass slight changes of the moisture content. As an example, water evaporation may occur (e.g. naturally), which could lead to slight changes.

Such a method is beneficial, since between the first and second expansion step, there maybe no expansion. Hence, it may not be required to substantially modify the moisture content. This contributes to obtaining a more efficient method of treating shredded tobacco stems.

According to a 3rd embodiment, in any one of the preceding embodiments, the first expansion step and/ or second expansion step comprise(s) contacting the shredded tobacco stems with steam, preferably a steam jet under pressure.

Contacting means that there is an interaction of the shredded tobacco stems and the steam. It may be sufficient that either the first or the second expansion step comprise contacting the shredded tobacco stems with steam. Preferably, both steps comprise contacting the shredded tobacco stems with steam.

Steam is beneficial in that it facilitates opening the structure of the shredded tobacco stems and enhances diffusion into interior portions of the stems. Thus, such an arrangement promotes efficient expansion of the shredded tobacco stems. Furthermore, steam may be applied with the aid of a heating tunnel or an STS (Steam Treated Stem) unit. It is appreciated that steam under pressure further enhances penetration by water.

According to a 4th embodiment, in any one of the preceding embodiments, the moisture content of the shredded tobacco increases by at most 5 percentage points OV, preferably at most 3 percentage points OV, most preferably at most 2 percentage points OV after the first and/or second expansion steps.

This embodiment is to be understood in such a manner that, e.g. after the first expansion step, the moisture content is increased by at most 5 percentage points OV compared to the moisture content before the first expansion step. In an illustrative example, a 5 percentage points increase of the moisture content (OV) means that the moisture content (OV) increases from about 30% (prior to the first expansion step) to 35% (after the first expansion step). The arrangement according to the 4th embodiment is further to be understood such that after the second expansion step, the moisture content maybe increased by e.g. at most 5 percentage points OV compared to the moisture content before the second expansion step.

It may be the case that an increase of the moisture content (OV) is the result of the application of steam during the first and/or the second expansion step. The amount of steam is carefully selected to provide and ensure an efficient expansion of the shredded tobacco stems. This culminates in an overall power consumption which is just sufficient to provide the required steam. Thus, the method is efficient. The method facilitates to manufacture products in an overall cost-effective manner. As an example, the products may be cheaper compared to conventional products as a net tobacco weight can be reduced. The moisture content (OV) is beneficially adjusted to obviate the need for more energy consumption during, for instance, subsequent steps. In some examples, it may be possible that the moisture content of the shredded tobacco increases by more than 5 percentage points OV.

According to a 5th embodiment, in any one of the 3rd or 4th embodiments, contacting the shredded tobacco stems with steam comprises injecting steam using an expansion steaming tunnel.

An expansion steaming tunnel facilitates an advanced and efficient expansion process. Such a tunnel may be easily integrated in the overall method. In another example, an STS (Steam Treated Stem) system or unit may be applied. STS may provide for (high) expansion without adversely affecting the product. As an example, STS may not negatively impact remaining parameters such as a moisture content, chemical and/or sensorial characteristics. This is appreciated by a user.

According to a 6th embodiment, in any one of the preceding embodiments, the method comprises cooling the shredded tobacco stems between the first and second expansion steps, wherein cooling optionally comprises decreasing a temperature of the shredded tobacco stems below 45°C, preferably below 40°C, more preferably below 35°C, most preferably below 30°C. Cooling means that a temperature of the shredded tobacco stems is at least slightly reduced. Cooling between the first and the second expansion steps is to be understood such that cooling occurs after the end of the first and before the start of the second expansion step. Thereby, the first and the second expansion steps may be considered as separate steps, wherein both steps are separated by a cooling step.

Cooling may be established by passive or by active cooling means. Passive cooling may be understood as cooling that takes place during storing, resting, lifting, moving and/or aging the shredded tobacco stems. Active cooling means that there are, for instance, one or more cooling conveyors arranged to cool down the shredded tobacco stems. A cooling conveyor may be understood as a cooling belt. In one example, ambient or cold air may pass through or may come in contact with shredded tobacco stems for the purpose of cooling.

According to a 7th embodiment, in any one of the preceding embodiments, the method comprises aging the shredded tobacco stems between the first and second expansion step by storing the shredded tobacco stems for at least 1 minute, preferably for at least 5 minutes, more preferably for at least 10 minutes, most preferably for at least 15 minutes, and/or storing the shredded tobacco stems for at most 240 minutes, preferably for at most 180 minutes, more preferably for at most 140 minutes, most preferably for at most 120 minutes.

Aging may be understood as a conditioning step or something similar. It may be possible to allow for some resting of the shredded tobacco stems. For instance, aging could take place in a buffer box, a pre-blender silo, a bulking silo and/or a (full) batch size blending silo. The aging time in a buffer box may be about 15 minutes. The aging time in a pre-blender silo may be about 30 minutes. The aging time in a (full) batch size blending silo may be about 120 minutes or more. In some but not all examples, aging the shredded tobacco stems maybe understood as storing the shredded tobacco stems.

Aging creates a high flexibility of the cell structure of the shredded tobacco stems. It is particularly appreciated that the time for aging, e.g. storing the shredded tobacco stems, maybe adjusted depending on the aging process. This provides the advantage of an improved cell structure, which may be adjusted to take full advantage of the second, subsequent expansion step. Thus, the overall efficiency of expansion is increased. In some cases, it may be feasible to combine a step of aging with a step of cooling. Thus, the number of steps may advantageously be reduced. In other examples, cooling may be performed separately from aging (e.g. using a cooling conveyor).

According to an 8th embodiment, in any one of the preceding embodiments, the method comprises aging the shredded tobacco stems before the first expansion step by storing the shredded tobacco stems for at least i minute, preferably for at least 5 minutes, more preferably for at least 10 minutes, most preferably for at least 15 minutes, and/or storing the shredded tobacco stems for at most 240 minutes, preferably for at most 180 minutes, more preferably for at most 140 minutes, most preferably for at most 120 minutes.

With the above arrangement, an aging step is also provided before, i.e. prior to the first expansion step. Such an aging step may be similar to the aging step between the first and the second expansion steps. Furthermore, such an aging step bears the potential to improve water penetration of the shredded tobacco stems in the first expansion step. This improves the expansion of the shredded tobacco stems.

In the aging step before the first expansion step, the temperature may not be decisive for determining an aging time. That maybe the case, as there is substantially no heating or not direct heating before first expansion step. In other words, the shredded tobacco stems may have substantially ambient temperature. Therefore, the aging time could also be reduced. However, the aging time should preferably not be less than 5 minutes.

According to a 9th embodiment, in any one of the preceding embodiments, the moisturized shredded tobacco stems provided in step (a), before the first expansion step, have a moisture content of at least 10% OV, preferably at least 20% OV, most preferably at least 30% OV, and/or of at most 50% OV, preferably at most 45% OV, most preferably at most 40% OV.

According to the above arrangement, the shredded tobacco stems are provided with sufficient moisture content (e.g. in oven volatiles, OV) for the subsequent processes. Such moisture content could be provided for by soaking the shredded tobacco stems in a liquid. The liquid may comprise water or other suitable fluids. Thus, the tobacco stems may moisturize or may be moisturized. It can also be feasible to flatten and cut the shredded tobacco stems after soaking.

According to a 10th embodiment, in any one of the preceding embodiments, the method comprises drying the shredded tobacco stems after the second expansion step.

Drying may be achieved by passive or by active drying means. Passive drying may be understood as drying that takes place during storing, resting, lifting and/or moving the shredded tobacco stems. Preferably active drying is performed, to provide an efficient overall method. Active drying is achieved using a dryer, for instance, with one or more fluidized bed dryers, a flash tower dryer, a rotary dryer and/ or band dryer. Thus, a moisture reduction may be achieved which is beneficial for reaching a targeted moisture content.

As an example, the moisture content value targeted or aimed at may be about n% to 14% in oven volatiles (OV). It may also be feasible that the fill value is substantially fixed thereby. This may be understood in such a way that the fill value may be corrected to the moisture content value targeted.

According to an 11th embodiment, in the preceding embodiment, drying comprises reducing the moisture content to less than or equal to 20% OV, and/ or to more than or equal to 10% OV.

The shredded tobacco stems should be dried down to a target moisture content which suits the need of a blend and/or type of shredded tobacco stems used. One reason why this should be done is that the different tobacco materials may have different starting moisture contents.

It is also advantageous to dry down to a value which is slightly higher than a targeted moisture content value, in order to account for slight losses of moisture content which may occur in subsequent process steps. Thereby, such a loss maybe compensated. Furthermore, slight variations or fluctuations may occur during processing. As an example, these variations or fluctuations may depend on process parameters (e.g. temperature and/or humidity). Accordingly, such fluctuations may also be accounted for by providing a range of moisture content of about io% to 20%.

The specified moisture content of the final product should preferably be the same as or at least similar to the one of the 11th embodiment. In one example, a moisture content in the final product maybe based on measurements of one or more samples. Based on such measurements, slight variations to a drying step may be performed to reach a moisture content value targeted.

According to a 12th embodiment, in any one of the 10th or 11th embodiments, the shredded tobacco stems have a fill value, after drying, of at least about 30%, preferably at least 35%, more preferably at least 40%, even more preferably at least 50%, most preferably at least 60% more than the fill value of the shredded tobacco stems before the first expansion step.

According to the above embodiment, an increased fill value after drying is provided. The fill value after drying may be understood as the fill value of the shredded tobacco stems prevailing at the end of the drying. It may also be understood as the fill value of the shredded tobacco stems prevailing directly after the drying. As an example, a fill value from 500 ml/ too g (before the first expansion step) increasing to 700 ml/ too g (after drying) may correspond to value of 40% as specified according to this embodiment. It may be possible that a determination of such a fill value could be performed at a standardized (or reference or normalized) moisture content value.

Applicable standardized moisture content values may be in the range of 11% to 14%, e.g. 12.5%.

According to a 13th embodiment, in any one of the 10th to 12th embodiments, the shredded tobacco stems after the second expansion step have a fill value of at least 700 ml/ too g, preferably comprised between 750 ml/ too g and 850 ml/ too g.

As explained above, the fill value may depend on the moisture content in oven volatiles (OV). Thus, according to the above embodiment, the fill value of the shredded tobacco stems after the second expansion step may be measured at a moisture content of about 12.5% OV. The above specified fill values may also be provided at a target moisture content which maybe (slightly) higher and/or lower moisture content (OV). However, for control, the fill value should be based on 12.5% OV.

According to a 14th embodiment, in any one of the preceding embodiments, the shredded tobacco stems before the first expansion step have a fill value of at most 600 ml/ 100 g, preferably of at most 550 ml/100 g, and/ or of at least 400 ml/100 g, preferably of at least 550 ml/100 g. Optionally, the fill value may be measured/ determined at a target moisture content of 12.5% OV.

It may be possible that a determination of a fill value (this may apply to substantially all fill values described herein) could be performed at a standardized (or reference or normalized) moisture content value. Typical standardized (or reference or normalized) moisture content values may be in the range of 11% to 14.5%, e.g. 12.5% OV. In one example, the shredded tobacco stems are adjusted (e.g. by drying or moisturizing) to such a standardized moisture content before measuring/determining the fill value. It may be the case that a variation of 1% OV could give rise to a difference in the fill value of about 50 ml/ 100g.

It may be possible that the standardized moisture content value may be the same as a target moisture content as used herein.

The same or similar explanations as outlined in the context of the previous embodiment may apply mutatis mutandis for this embodiment.

Apparatus

A 15th embodiment of the invention is directed to an apparatus configured to perform the method according to any one of the preceding claims, comprising:

(a) means for providing moisturized shredded tobacco stems;

(b) means for expanding the shredded tobacco stems in a first expansion step;

(c) means for further expanding the shredded tobacco stems in a second expansion step;

(d) optionally means for cooling/ drying the shredded tobacco. The features and advantages as mentioned and explained above with respect to the method according to any one of the 1st to 14th embodiments of the invention apply also to the apparatus as outlined in the above embodiment.

Means for providing moisturized shredded tobacco stems may comprise any means that are suitable for providing something. As an example, the means could be one or more belts or one or more conveyors.

Means for expanding the shredded tobacco stems in a first expansion step may comprise any means that are suitable to expand shredded tobacco stems. In a particular example, the means may comprise one or more or a combination of the following: a heating tunnel, an STS (Steam Treated Stem) unit or generally a steam jet under pressure.

The means for further expanding the shredded tobacco stems in a second expansion step may comprise similar means as the means for expanding the shredded tobacco stems in a first expansion step. In one example, the means of the second expansion step could be the means of the first expansion step.

The optional means for cooling the shredded tobacco stems may be any means suitable for at least partially a temperature of the shredded tobacco stems.

The optional means for drying the shredded tobacco stems may be any means suitable for at least partially reducing a moisture content in oven volatiles (OV) of the shredded tobacco stems.

Tobacco product

A 16th embodiment of the invention is directed to a tobacco product, such as an expanded shredded stem tobacco product, comprising shredded tobacco stems, the tobacco product being obtainable by the method according to any one of embodiments 1 to 14 and having a fill value of at least about 30%, preferably at least 35%, more preferably at least 40%, even more preferably at least 50%, most preferably at least 60% more than a fill value of the shredded tobacco stems before application of the method. For the determination of such a fill value (e.g. at a standardized (or reference or normalized) moisture content value) the same applies as described herein elsewhere.

The features and advantages as mentioned and explained above with respect to the method according to any one of the 1st to 14th embodiments of the invention and/ or to the apparatus according to the 15th embodiment of the invention apply also to the tobacco product as outlined in the above embodiment.

The tobacco product may refer to any product made or sold in the sector of the tobacco industry. A tobacco product may include tobacco of pipes, cigarettes, cigarillos, cigars. It may comprise tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco and/ or tobacco substitutes or any combination thereof. In addition, tobacco products such as snus, snuff, solid or hard tobacco, and heat-not-burn may be comprised. The tobacco product may be a smoking article, vaping article, aerosol generating article or the tobacco product may be incorporated into such a smoking article.

Brief description of the figures

In the following, preferred embodiments are described, by way of example only. Reference is made to the following accompanying figures:

Fig. 1 is a flow chart of a method according to an embodiment of the invention;

Fig. 2 is a flow chart of a method according to a further embodiment of the invention;

Fig. 2a is a flow chart of a method according to yet a further embodiment of the invention;

Fig. 3 illustrates a diagram of the moisture content in percentage of oven volatiles at different steps of the method in accordance with an exemplary embodiment of the invention;

Fig. 4 is a diagram illustrating the fill value of the tobacco stems at different steps of the method in accordance with an exemplary embodiment of the invention; and Fig. 5 illustrates a tobacco product according to an embodiment of the invention compared to a tobacco product obtained by conventional methods.

Detailed description of preferred embodiments

In the following, the invention is described with reference to the accompanying figures in more detail. As detailed below, the embodiments are compatible and individual features of one embodiment may also apply to another embodiment.

Throughout the figures and their specification, the same reference numerals refer to the same elements, unless stated otherwise. The figures may not be drawn to scale, and the relative size, proportions, and depiction of elements in the figures may be exaggerated for the purpose of clarity, illustration, and convenience. The figures do not limit the scope of the claims but merely support the understanding of the invention.

Fig. i shows a flow chart of a method too of treating shredded tobacco stems according to an embodiment of the invention. The method too comprises the step of providing no moisturized shredded tobacco stems. This means that such moisturized shredded tobacco stems should at least be available or made available. For instance, the shredded tobacco stems should be available for the one or more subsequent method steps.

Shredded tobacco stems are tobacco stems which are at least partially processed; e.g., the stems may be cut or otherwise made into smaller pieces. Examples of tobacco which could be used here are Virginia, Burley, Oriental, (Galpao) Comum, Amarelinho and Maryland tobaccos, or any similar tobacco types and blends of any of these types.

The provided moisturized shredded tobacco stems should have a moisture content from about 30% to about 40% oven volatiles (OV). Most preferably the moisture content is about 36% OV.

The fill value of the shredded tobacco stems is about 450-550 ml/ too g, i.e. 450- 550 cc/100 g or 4-5-5.5 ml/g before expanding in the first expansion step 120 and/or before treating the shredded tobacco stems. As an example, such fill values are measured at a certain standardized (or reference or normalized or targeted) moisture content. As an example, such normalized moisture content may be between 11% to 14%, preferably 12.5% oven volatiles (OV). It may be beneficial to measure fill values at a targeted moisture content to reduce an impact on measurement results of the fill values. It is to be noticed that the fill values may not substantially alter (a variation of 1% OV could give rise to a difference of about 50 ml/ioog), if measurement is performed at different moisture content values.

The method 100 comprises the step of expanding 120 the shredded tobacco stems in a first expansion step. This may be done by subjecting the moisturized shredded tobacco stems to a steam injection (e.g. steaming tunnel). This is performed by a heating tunnel, an STS (Steam Treated Stem) unit or generally a steam jet under pressure (Supplier: Garbuio Dickinson). The processing conditions may consider a basic flow rate between about 1000 and 2600 kg/h (flow rate of raw material at the inlet of the unit) and steam flow rate between about 500 and 1000 kg/h (flow rate of steam injected into the expansion device pipe). By way of the steam injection, preferably under pressure, a sufficient penetration of the shredded tobacco stems can be achieved. It is possible to achieve a deep water penetration to the shredded tobacco stems and/ or their cells. Subsequently, the pressure maybe released or reduced causing the steam to expand and the tobacco cells to increase in volume. Thus, the treated tobacco stems have an increased volume, i.e. they are expanded. In one example, the step of expanding 120 comprises water implosion, resulting in a further expansion of the shredded tobacco stems. As an example, water implosion may be understood as compressing, collapsing molecules of water inward using phase conjugation and/or centripetal implosion.

The step of expanding 120 the shredded tobacco stems in a first expansion step can also comprise subjecting the shredded tobacco stems to heat.

During expansion of the shredded tobacco stems in the first expansion step 120, the moisture content (OV) of the shredded tobacco stems at least remains the same as before the first expansion step 120. After the first expansion step 120, the moisture content (OV) is about 1 to 5, preferably 1 to 2 percentage points greater than before the first expansion step 120. A moisture content (OV) which is greater by 2 percentage points means that the moisture content (OV) increases from, e.g. 36% (prior to the first expansion step 120) to 38% (after the first expansion step 120). The method 100 comprises the step of further expanding 130 the shredded tobacco stems in a second expansion step. A similar mechanism of expansion as in the first expansion step 120 is applied in the second expansion step 130. Such second expansion 130 leads to a water implosion as described herein resulting in a further expansion of the shredded tobacco stems.

Directly after the second expansion step 130, the shredded tobacco stems have a moisture content which is greater than or equal to the moisture content after the first expansion step 120. The moisture content is measured in oven volatiles (OV). Thus, after further expansion of the shredded tobacco stems in the second expansion step 130, the moisture content (OV) of the shredded tobacco stems is about 1 to 5, preferably 1 to 2 percentage points greater than before the second expansion step 130. A moisture content (OV) which is greater by 1 percentage point means that the moisture content (OV) increases from, e.g. 38% (prior to the second expansion step 130) to 39% (after the second expansion step 130).

The fill value of the shredded tobacco stems after expanding the shredded tobacco stems in the second expansion step 130 is at least 20%, preferably at least 30%, more preferably at least 35%, even more preferably at least 40%, further more preferably at least 50%, most preferably at least 60% and most preferably at least 40% greater than the fill value of the shredded tobacco stems before expanding the shredded tobacco stems in the first expansion step 120. As described herein, the fill value could be about 450-550 ml/100 g, i.e. 450-550 cc/100 g or 4.5-5.5 ml/g before expanding the shredded tobacco stems in the first expansion step 120 and/or before treating the shredded tobacco stems; after expanding the shredded tobacco stems in the second expansion step 130, the fill value is about 750-850 ml/100 g, i.e. 750-850 cc/100 g or 7-5-8.5 ml/g. The fill value could be measured at a moisture content of about 12.5% oven volatiles (OV). The fill value may be slightly different if other normalized moisture content values are applied. The fill value of the shredded tobacco stems after expanding the shredded tobacco stems in the second expansion step 130 may also be more than at least 60% greater than the fill value of the shredded tobacco stems before expanding the shredded tobacco stems in the first expansion step 120. As an example, an increase from 450 ml/100 g to 850 ml/ioog may correspond to an increase of 89%. With the above embodiment of a method loo according to the invention, the inventors found a viable way to meet the demand for providing expanded shredded tobacco stems with plain taste when combusted. In particular, conventional shredded tobacco stems have a low fill value (or filling value, filling power, or filling capacity) insufficient aroma, high irritation, low strength and strong wood taste. The above embodiment ensures that these disadvantages are overcome and that less impairment by e.g. a woody taste is provided. This is appreciated by the user. Furthermore, a consistent and predictable expansion volume is ensured. Thus, the method too is suitable for automation, which makes the method too more efficient. The final product can be used for instance for cigarettes.

As described herein in greater detail elsewhere, it is noted that the moisture content of the shredded tobacco stems is not substantially increased during the first expansion step 120 and / or the second expansion step 130. The following non-limiting example may serve as an explanation as to why the moisture content of the shredded tobacco stems is not substantially increased during the first expansion step 120 and / or the second expansion step 130: Without wishing to be bound by theory, it is believed that steam can be injected in heating means, such as a heating tunnel, which can be a vibrational conveyor having holes. The steam pressure maybe between 2 to 6 bar, preferably 2.5 to 4.5 bar, most preferably approximately 4 bar.

In order to avoid steaming in primary, one may remove the steam. For this purpose, suction means, such as a suction hood may be used. The suction means may be provided on top of the heating means. In one example, this may be referred to as an aspiration hood.

Since increasing the moisture content of the shredded tobacco stems may negatively affect a capacity of diying means, such as a dryer, and / or may negatively affect taste of the final product, process parameters of the heating means and the suction means are setup to ensure, that there is no significant impact on the moisture content of the tobacco stems.

This approach facilitates that the tobacco stems can be expanded and not that the tobacco stems are conditioned and / or that their moisture content is increased (which may have adverse effects as described elsewhere herein). It was surprisingly found that this is a previously unknown side effect, which bears the potential to make the expansion process more efficient.

Fig. 2 shows a flow chart of a method 200 according to an embodiment of the invention, which may, in part, be compatible with the embodiment of method 100 of the preceding figure. The boxes depicted with dashed borders may represent optional method steps.

Steps 210, 220 and 230 correspond to steps 110, 120 and 130, respectively, as outlined above in the preceding figure.

The method 200 of this further embodiment is similar to the one presented in the previous figure. In addition, the method 200 comprises a step 205 comprising soaking the tobacco stems to be provided in water. This may be referred to as conditioning and is beneficial for the subsequent steps. In particular, the moisture content of the shredded tobacco stems can be adjusted in a controlled and repeatable manner.

Step 205 further comprises flattening the tobacco stems. This may be achieved by applying rollers comprising a gap in between. Such a gap could be 1 mm. Step 205 also comprises cutting the tobacco stems, e.g. to pieces of less than about 0.5 mm.

The method 200 of this further embodiment also comprises a step 215 of aging and/or cooling. Aging (a type of conditioning) means that time for some resting of the shredded tobacco stems is provided for. Aging can take place in a buffer box, a preblender silo, a bulking silo and/or a (full) batch size blending silo. The aging time in a buffer box may be, for instance, about 15 minutes. The aging time in a pre-blender silo maybe, for instance, about 30 minutes. The aging time in a (full) batch size blending silo may be, for instance, about 120 minutes or more. Typically, the aging time in this step 215 is not less than 5 minutes.

The step 215 can follow the step of providing 210 moisturized shredded tobacco stems. The step 215 precedes the step of expanding the shredded tobacco stems in a first expansion step 220. This is beneficial, because water penetration into the cells of the shredded tobacco stems is enhanced, which makes the first expansion step 220 more efficient. The step of cooling within step 215 is optional (as indicated by the dashed border of the box in this figure). It could depend on the initial temperature of the provided tobacco stems and/or the subsequent process steps.

The method 200 of this further embodiment additionally comprises a step 225 of aging and/or cooling performed after the first expansion step 220. Also in this step, aging may be performed as set forth above. Aging 225 creates a higher flexibility of the cell structure of the shredded tobacco stems.

Cooling within step 225 means that the temperature of the shredded tobacco stems is decreased to a value below 45°C, preferably below 40°C, more preferably below 35°C, most preferably to a value below 30°C. Cooling between the first 220 and the second 23oexpansion steps means that cooling occurs after the end of the first 22oand before the (start of the) second 23oexpansion step. The first 220 and the second 23oexpansion steps are discernable as separate steps. They are separated by an aging and/or cooling step 225.

Cooling can be established by passive or by active cooling means. Passive cooling means that cooling takes place during storing, resting, lifting, moving and/or aging the shredded tobacco stems. Active cooling can be performed with one or more cooling conveyors (or belts) arranged to cool down the shredded tobacco stems. It is also viable to use ambient or cold air for cooling. As an example, such air may be forced to come in contact with shredded tobacco stems. Thus, forced convection may aid cooling.

The method 200 of this further embodiment additionally comprises a step 240 of cooling, drying, sieving and/or packing. The step 240 follows the step of expanding the shredded tobacco stems in the second expansion step 230.

Cooling 240 may be performed as explained above with respect to cooling within step 225.

Drying 240 can be performed using passive or active drying means. Passive drying can take place during storing, resting, lifting and/or moving the shredded tobacco stems. Active drying is beneficial to expedite the method, which makes it more efficient. Active drying comprises the application of one or more fluidized bed dryers, a flash tower dryer, a rotary dryer and/ or band dryer. Thus, a moisture reduction can be achieved, which is beneficial for reaching a targeted moisture content. Drying 240 leads to a moisture content of less than or equal to 20% in oven volatiles (OV), and/or to greater than or equal to 10% OV. Preferably, the moisture content value targeted or aimed at is about 11% to 14% OV.

Sieving 240 may also be performed, which means a separation of e.g. heavy and/or solid particles from the shredded tobacco stems. This may be dependent upon the size and/or weight of the particles. It improves the quality of the final product.

Packing 240 may also be comprised by the method 200. Packing means that the shredded tobacco stems are packaged, e.g. by according to their size, so as to obtain a final product of shredded tobacco stems (which are expanded). During packing, the shredded tobacco stems have about the fill value that was present (directly) after the second expansion step 230. Thus, the fill value is about 750-850 ml/100 g, i.e. 750- 850 cc/ too g or 7-5-8.5 ml/g. This is based on a moisture content of about 12.5% oven volatiles (OV).

Fig. 2a is a flow chart of a method 300 according to yet a further embodiment of the invention. In here, the method steps of method 200 of the preceding figure are described in more detail. Further, in this embodiment, the optional method steps of the preceding figure are indicated.

Tobacco stems are soaked in water, flattened, cut, aged/ cooled (corresponding to method step 205). Further, tobacco stems are provided (corresponding to method step 210). Subsequently, a first expansion step is performed (corresponding to step 220). Aging/ cooling is performed as well (corresponding to step 225). A second expansion step is performed (corresponding to step 230). Afterwards, cooling, drying, sieving and packing is performed (corresponding to method step 240).

Fig. 3 shows a diagram of the moisture content in oven volatiles (OV), i.e. in percentage of OV at different steps of the method in accordance with an exemplary embodiment of the invention. Steps 210, 220 and 230 correspond to steps 110, 120 and 130, respectively, as described herein.

As explained above, the moisture content refers to oven volatiles (OV). For that it is to be noted that oven dry mass is the mass that remains after the volatile substances have been driven off by heating. The oven dry mass is expressed as a percentage of the total mass. Oven volatiles (OV) are the mass of volatile substances that were driven off. The moisture content (oven volatiles) can be measured as the reduction in mass when a sample, e.g. a tobacco sample is dried in a forced draft oven at a temperature regulated to no°C ± 1°C for three hours ± 0.5 minutes. Different measurement standards of the moisture content may also be applied.

In the exemplary embodiment of this figure, two graphs are indicated. On the Y-axis, the moisture content is shown. On the X-axis, exemplary method steps are indicated in accordance with the nomenclature as set forth above.

The lower graph, i.e. the graph having circles filled in black shows a moisture content of about 30% OV before expanding 120 the shredded tobacco stems in a first expansion step. After expanding 120 the shredded tobacco stems in a first expansion step, the moisture content is not lower than 30% OV. The moisture content after expanding 120 the shredded tobacco stems in a first expansion step 120 is about 32% OV, e.g. it increased by 2% OV. After further expanding 130 the shredded tobacco stems in a second expansion step, the shredded tobacco stems have a moisture content in OV which is greater than or equal to the moisture content in OV after the first expansion step 120. In this example, the moisture content is 34% OV after further expanding 130 the shredded tobacco stems in a second expansion step. After the step of drying, e.g. step 240, the moisture content in OV is at least about 10% OV and at most about 20% OV. In this exemplary embodiment, the moisture content is about 11%. The expressions “before” or “after” a specific method step can be understood as directly before or after such step. Thus, there maybe no further steps in between. In this manner, the moisture content after expanding 120 the shredded tobacco stems in a first expansion step 120 can be understood as the moisture content directly after (or even at the end of) the first expansion step 120. The upper graph, i.e. the graph having circles filled in white shows a moisture content of about 36% OV before expanding 120 the shredded tobacco stems in a first expansion step. After expanding 120 the shredded tobacco stems in the first expansion step, the moisture content is not lower than 36% OV, namely about 37% OV, i.e. it has increased by 1% OV (1 percentage point). After further expanding 130 the shredded tobacco stems in a second expansion step, the shredded tobacco stems have a moisture content in OV which is greater than or equal to the moisture content in OV after the first expansion step 120. In this example, the moisture content is 38% OV after further expanding 130 the shredded tobacco stems in a second expansion step. After the step of drying, e.g. step 240, the moisture content in OV is at least about 10% OV and at most about 20% OV. In this exemplary embodiment, the moisture content is about 14%.

Fig. 4 shows a diagram of the fill value of the tobacco stems at different steps of the method in accordance with an exemplary embodiment of the invention.

Steps 210, 220 and 230 correspond to steps 110, 120 and 130, respectively, as described herein.

In the exemplary embodiment of this figure, two graphs are indicated. On the Y-axis, the fill value is shown. On the X-axis, exemplary method steps are indicated in accordance with the nomenclature as set forth above.

The lower graph, i.e. the graph having circles filled in black shows a fill value of about 450 ml/ too g before expanding 120 the shredded tobacco stems in a first expansion step. After expanding 120 the shredded tobacco stems in the first expansion step, the fill value is about 550 ml/ too g. After further expanding 130 the shredded tobacco stems in a second expansion step, the shredded tobacco stems have a fill value of about 750 ml/ too g. After the step of diying, e.g. step 240, the fill value is about the same, e.g. about 750 ml/ too g.

The upper graph, i.e. the graph having circles filled in white shows a fill value of about 550 ml/ too g before expanding 120 the shredded tobacco stems in a first expansion step. After expanding 120 the shredded tobacco stems in the first expansion step, the fill value is about 750 ml/ too g. After further expanding 130 the shredded tobacco stems in a second expansion step, the shredded tobacco stems have a fill value of about 850 ml/ 100 g. After the step of drying, e.g. step 240, the fill value is about the same, e.g. about 850 ml/100 g.

The increased fill value reached or achieved after the second expansion step 130, e.g. directly after the second expansion step 130 (in some cases this maybe at the end of the second expansion step 130) applies therefore also to the final product, i.e. the tobacco product. This is beneficial for the final product, since it can benefit from the advantageous effects associated with the increased fill value of the shredded tobacco stems. Thus, no substantial loss in the fill value after the second expansion step 130 occurs, which is appreciated.

Fig. 5 shows a tobacco product 1 according to an embodiment of the invention (righthand side of this figure) compared to a tobacco product 1’ obtained by conventional methods (left-hand side of this figure) in a schematic way.

The tobacco product 1 is an expanded shredded stem tobacco product, comprising shredded tobacco stems 10, with a fill value which is at least about 30%, preferably 35%, more preferably at least 40%, even more preferably at least 50%, most preferably at least 60% more than a fill value of the shredded tobacco stems before application of the method too according to an embodiment of the invention.

For the determination of such a fill value (e.g. at a standardized (or reference or normalized) moisture content value) the same applies as described herein elsewhere.

The tobacco product 1 is any product made in or sold in the sector of the tobacco industry, e.g. pipes, cigarettes, cigarillos, cigars or anything similar. The tobacco product 1 can also be a smoking article or can be incorporated into such a smoking article. In such a manner, it is appreciated that the tobacco product 1 benefits from the advantageous effects of an increased fill value, which is imparted into the tobacco product by the inventive method.

The figure highlights that the increased fill value may be directly recognizable in the tobacco product 1. It can be observed that the volume of the shredded tobacco stems 10 is higher compared to a conventional tobacco product 1’ comprising shredded tobacco stems 10’ for the same overall weight of the shredded tobacco stems 10’, 10. Further, the overall integrity, mechanical stability and rigidity of the tobacco product 1 may be improved. Furthermore, by way of the reduced weight of the shredded tobacco stems 10, the taste may be improved, since less cellulosic components may be received by a user. The tobacco product 1 can be a cigarette (e.g. if other parts for a cigarette are added) having a filter. In such an example, a reduced net tow weight may also be positively recognized and measured in the tobacco product 1.

The scope of protection is determined by the claims and is not limited by the embodiments disclosed in the above figures.

List of reference signs

1 tobacco product

1’ conventional tobacco product

10 (expanded) shredded tobacco stems

10’ conventional (expanded) shredded tobacco stems

100, 200, 300 method

205 method step(s): soaking/flattening/cutting

110, 210 method step: providing

215 method step(s): aging/cooling

120, 220 method step: first expansion

225 method step(s): aging/cooling

130, 230 method step: second expansion

240 method step(s): cooling/drying/sieving/packing

Claims

Claims A method of treating shredded tobacco stems, comprising:

(a) providing moisturized shredded tobacco stems;

(b) expanding the shredded tobacco stems in a first expansion step;

(c) further expanding the shredded tobacco stems in a second expansion step, wherein the shredded tobacco stems have a moisture content directly after the second expansion step which is greater than or equal to the moisture content after the first expansion step, wherein the moisture content is measured in oven volatiles (OV). The method according to the preceding claim, wherein the shredded tobacco stems are kept at a moisture content of at least 10% OV, preferably at least 20% OV, most preferably at least 30% OV during the second expansion step, preferably during the first and second expansion steps, most preferably during and between the first and second expansion steps; and/or wherein the shredded tobacco stems are kept at a moisture content of at most 50% OV, preferably at most 45% OV, most preferably at most 40% OV during the second expansion step, preferably during the first and second expansion steps, most preferably during and between the first and second expansion steps. The method according to any one of the preceding claims, wherein the first expansion step and/or second expansion step comprise(s) contacting the shredded tobacco stems with steam, preferably steam jet under pressure. The method according to any one of the preceding claims, wherein the moisture content of the shredded tobacco increases by at most 5 percentage points OV, preferably at most 3 percentage points OV, most preferably at most 2 percentage points OV after the first and/or second expansion steps. The method according to any one of claims 3 or 4, wherein contacting the shredded tobacco stems with steam comprises injecting steam using an expansion steaming tunnel. The method according to any one of the preceding claims, further comprising cooling the shredded tobacco stems between the first and second expansion steps, wherein cooling optionally comprises decreasing a temperature of the shredded tobacco stems below 45°C, preferably below 4O°C, more preferably below 35°C, most preferably below 3O°C. The method according to any one of the preceding claims, further comprising aging the shredded tobacco stems between the first and second expansion step by storing the shredded tobacco stems for at least 1 minute, preferably for at least 5 minutes, more preferably for at least 10 minutes, most preferably for at least 15 minutes, and/or storing the shredded tobacco stems for at most 240 minutes, preferably for at most 180 minutes, more preferably for at most 140 minutes, most preferably for at most 120 minutes. The method according to any one of the preceding claims, further comprising aging the shredded tobacco stems before the first expansion step by storing the shredded tobacco stems for at least 1 minute, preferably for at least 5 minutes, more preferably for at least 10 minutes, most preferably for at least 15 minutes, and/or storing the shredded tobacco stems for at most 240 minutes, preferably for at most 180 minutes, more preferably for at most 140 minutes, most preferably for at most 120 minutes. The method according to any one of the preceding claims, wherein the moisturized shredded tobacco stems provided in step (a), before the first expansion step, have a moisture content of at least 10% OV, preferably at least 20% OV, most preferably at least 30% OV, and/or of at most 50% OV, preferably at most 45% OV, most preferably at most 40% OV. The method according to any one of the preceding claims, further comprising drying the shredded tobacco stems after the second expansion step. The method according to the preceding claim, wherein drying comprises reducing the moisture content to less than or equal to 20% OV, and/or to greater than or equal to 10% OV. The method according to any one of claims 10 or 11, wherein the shredded tobacco stems after drying have a fill value of at least about 30%, preferably at least 35%, more preferably at least 40%, even more preferably at least 50%, most preferably at least 60% more than the fill value of the shredded tobacco stems before the first expansion step. The method according to any one of claims 10 to 12, wherein the shredded tobacco stems after the second expansion step have a fill value of at least 700 ml/100 g, preferably comprised between 750 ml/100 g and 850 ml/100 g. The method according to any one of the preceding claims, wherein the shredded tobacco stems before the first expansion step have a fill value of at most 600 ml/100 g, preferably of at most 550 ml/100 g, and/or of at least 400 ml/100 g, preferably of at least

550 ml/100 g. An apparatus configured to perform the method according to any one of the preceding claims, comprising:

(a) means for providing moisturized shredded tobacco stems;

(b) means for expanding the shredded tobacco steams in a first expansion step;

(c) means for further expanding the shredded tobacco stems in a second expansion step;

(d) optionally means for cooling/ drying the shredded tobacco .