KR0169485B1 - Method for the extraction of roasted and ground coffee - Google Patents

Abstract

The present invention relates to a method of extracting roasted and ground coffee. Extraction water is fed to one end of the extraction vessel containing roast and ground coffee and the coffee extract is recovered from the other end. Intermittently stop the flow of water to the container and the extract discharged from the container, and intermittently discharge the extracted roast and ground coffee from the extraction container, and at the same time to remove some of the unextracted coffee to the other end Through the container. Coffee in the brewing vessel is moved countercurrent to the extract water flow. The method of the present invention provides a method of producing coffee that is less complex, more easily adjusted, has a good balanced aroma with a small investment, and is more fragrant.

Description

Extraction Method of Roasted Powdered Coffee

1 is a front view of an extraction container for roasted powder coffee extraction.

* Explanation of symbols for the main parts of the drawings

2: upper blow case 1, 3, 7, 7, valve

4: second end of extraction vessel 5: extraction vessel

6: first end of extraction container 6: first end of extraction container

8: lower blow case

The present invention relates to a method for extracting roasted powdered coffee. More specifically, the present invention relates to a method of withdrawing coffee extract from the other end of the container while supplying extract water to one end of the extraction container containing roasted powdered coffee. Dispensing and dispensing into the container is periodically stopped and the unextracted coffee is intermittently introduced into the brewing container while simultaneously discharging a portion of the extracted coffee. The present invention produces roasted powdered coffee extract with improved aroma. The term is improved at higher concentrations or higher yields than conventional extraction systems, or at lower operating conditions of time and temperature for the same yield or concentration. In either case, the fragrance is substantially improved.

Extraction methods of roasted powdered coffee for soluble coffee processing are often carried out in fixed bed countercurrent extraction batteries with mostly 6 to 8 columns. Hot extracted water, usually above 160 ° C., is fed to a column containing the most spent coffee (ie, the coffee from which the solids are extracted) with the most active ingredients, thereby thermally hydrolyzing the coffee. This extract is increasingly richer in coffee solids as it progresses through columns containing less extracted coffee. The last column of the extraction column from which the coffee extract is taken out contains the freshest (least extracted) coffee, which is then extracted under air. After all extractable solids, which are practically soluble, have been removed from the coffee with the most active ingredient extracted, periodically, the column containing the coffee is separated from the apparatus and a new column containing fresh coffee is placed on the stream. The flow of the extract is adjusted so that the hot extractant is fed to the column having the most new active ingredient extracted and the corresponding regulating device made throughout the device, therefore, the countercurrent extraction device is discontinuous and such a system is intended to This requires considerable valves and pipes (complex manifolds) for flow control. Typical countercurrent extraction devices are described in Ornfelt, U.S. Patent No. 2,515,730, Guggenheim et al., U.S. 2,915,399 and in Sivetz and Futte, Coffee Processing Technology, AVI Publishing, 1963, Vol. 281-294, Westport, Connecticut.

It is an object of the present invention to provide a method for extracting soluble solids from roasted powdered coffee in an effective way to maintain the aroma quality of the soluble solids.

Another object of the present invention is to provide a method for extracting roasted powdered coffee almost continuously, which does not require the complicated manifolds associated with conventional countercurrent extraction devices.

Another object of the present invention is to provide a method of extracting roasted powdered coffee which is more effective than conventional countercurrent extraction devices due to the substantially larger number of equivalent extraction steps obtainable with the method of the present invention.

We have found that the object of the present invention is met by a method of extracting roasted powdered coffee in a single extraction vessel. Extraction water is supplied to one end of the extraction vessel and the coffee extract is taken out from the opposite end of the extraction vessel. According to the invention, soluble solids are extracted from roasted powdered coffee in an effective way to maintain the aroma quality of the coffee solids. In addition, due to the improved efficacy of the extraction method, roasted powdered coffee extracts, which have a high concentration or high yield of soluble solids at lower temperatures and shorter residence times, and which have a more similar aroma profile to sauted roasted powdered coffee, Can produce. Thus, roasted powdered coffee extracts are always produced which are excellent and have substantially improved aroma quality.

Roasted powdered coffee is extracted in the extraction container. As a container, a container for intermittently introducing fresh coffee and discharging the extracted coffee, as well as contacting the roasted powdered coffee with the extract when the extract flows through the container, is suitable. A preferred container is an elongate column in which roasted powdered coffee is maintained as a bed through which extracts pass. Such elongate columns are preferably about 7.5 to 23.0 m in length. The diameter of the column is determined taking into account the desired capacity and the preferred range of apparent flow rates described below. The column is installed vertically to provide the most convenient countercurrent flow of the extract and roasted ground coffee.

Since the column is most conveniently installed vertically, the extract water is fed to the bottom of the column and the coffee extract is taken out of the top of the column so that the extract flows upward through the bed of roasted powdered coffee and the coffee is directed downward. It is also desirable to allow it to be moved. Periodically, the input and discharge into the container can be stopped, the unextracted coffee is intermittently introduced into the extraction container, and some of the coffee with the most active ingredient extracted is discharged. Subsequently, supply of the extraction water to the container and extraction of the extract from the container can be resumed. Of course, after discharging the extracted coffee intermittently, the coffee is moved as a result of adding fresh roasted powdered coffee. In the case of supplying the extraction water to the bottom of the container, fresh coffee is put at the top of the container and the extracted coffee is taken out from the bottom so that the coffee flows counter to the flow of the extract. Thus, by installing the elongate column vertically, coffee is moved through the column mainly by gravity. Of course, it is possible to reverse the flow of the extract liquid and roasted powdered coffee so that the extract water is supplied to the top of the container, but it is not convenient at all.

As will be described later, it is possible to temporarily stop the supply of the extraction water to the extraction container and the withdrawal of the coffee extract from the container after a predetermined time. A portion of the fresh, unextracted roasted powdered coffee is introduced into the teapot end of the extraction vessel while discharging a portion of the extracted roasted powdered coffee from one end of the vessel. In the case of an elongate column, the fraction is measured for the volume of the coffee bed in the column, for example discharging 10% of the total volume of the column intermittently. The extracted roasted powdered coffee fractions are preferably discharged intermittently in an amount of 4 to 20% of the coffee bed included in the elongate column, and most preferably in an amount of 5 to 15% by volume.

Although roasted powdered coffee expands to nearly twice its original volume when wet and / or when concentrating and reducing the volume of the extract, the same volume of unextracted roasted powdered coffee can be introduced into the column when the coffee is dried. If the same volume of dry and fresh roasted powder coffee is substituted for the extracted coffee, the coffee may be difficult to swell properly and may not be properly brewed, however, 30.5 cm (1 foot) of For columns larger than fractions, diameter expansion does not appear to be a problem, therefore, for small columns, dry coffee can be introduced at about 1/2 of the volume of extracted coffee being discharged, moreover, flow of extract liquid. The speed should be adjusted to replenish the water absorbed in the roasted ground coffee. In another embodiment, the unextracted roasted powdered coffee is premoisturized prior to introduction into the elongate column, with the volume of coffee being simultaneously added and discharged at about the same time.

Once the addition of the unextracted roasted powdered coffee and the discharge of the extracted coffee are completed, the supply of the extraction water to the container and the extraction of the extract from the extraction container are resumed (assuming that the supply has been stopped in advance). Since the overall operation can be carried out very quickly (depending on the size of the fraction discharged), usually not more than a few minutes, this method is much more continuous than conventional countercurrent fixed bed extraction methods. Alternatively, the method of the present invention is essentially continuous, without the need to interrupt the introduction and discharge of the extract to the extraction vessel based on the shape of the particular apparatus.

The input of fresh coffee and the discharge of extracted coffee can be done in several arbitrary ways. For example, when freshly roasted powdered coffee is introduced into the upper column, the lower valve of the column is briefly opened to discharge the extracted roasted powdered coffee in a desired amount. At the same time, the top valve of the column is opened to inject the appropriate aroma of unextracted roasted ground coffee by gravity. Then both valves are closed. If the extraction vessel is maintained at a pressure above atmospheric pressure, this technique is not suitable.

Most preferably, the extraction vessel is introduced into and discharged from a so-called blow case installed above and connected to the extraction vessel. The blow case is individual containers of approximately the same volume as the unextracted coffee to be injected and the extracted roasted powdered coffee to be discharged, which can withstand pressures equal to or slightly higher than the pressure maintained in the extraction container. The blow case on the column is filled with an appropriate amount of fresh coffee and pressurized with compressed air or some liquid to a pressure slightly greater than the pressure maintained in the column. The valve at the bottom of the column is opened to fill the blow case with the discharged fraction of coffee, and the valve is closed. Almost simultaneously, the valve at the top of the column is opened and fresh roasted powdered coffee is introduced into the column under pressure. The upper blow case is then separated and the input and discharge to the column is resumed or continued. The use of the blow case is relatively simple, efficient and as fast as feeding and discharging into the extraction vessel by gravity.

1 shows one preferred embodiment for operating the method of the present invention. Under steady-state conditions, the extraction vessel 5 is filled with a bed of roasted powder coffee extracted to varying degrees. The feed water is fed to the first end 6 of the extraction vessel and the coffee extract is withdrawn from the second end 4 of the extraction vessel. The unextracted roasted powder coffee is periodically introduced into the blow case 2 through the valve 1. Valves 3 and 7 intermittently open simultaneously to discharge the unextracted roasted powdered coffee from the blow case 2 to the blow case 8 from the second end 6 of the extraction container. Subsequently, the valves 3 and 7 are closed. The valve 9 is then opened to drain the roasted powdered coffee extracted from the blow case 8. The additional unextracted roasted powder coffee is introduced into the blow case 2 through the valve 1, and this process is repeated.

The operation of the present invention has been described so far, and the following describes the significantly improved process efficacy and quality of the coffee extract obtained from the operation. The process of the present invention is more effective for the extraction of roasted powdered coffee solids, since it has more steps to be effective than conventional fixed bed countercurrent extraction devices of 6 or 8 columns, the term being referred to as Perry ), Chemical Engineers' Handbook, 3rd Edition, McGraw Hill, 1950, page 716, which is used in its conventional chemical engineering sense, which is incorporated herein by reference. This improved potency increases the concentration of coffee solids in the coffee extract taken compared to conventional extraction devices at equivalent operating parameters. In addition, even if all operating variables were fixed constantly, higher levels of coffee aroma were found in the coffee extracts of the present invention as measured by gas chromatography compared to conventional extractors. In addition, the level of coffee aroma is more balanced, close to the level found in roasted ground coffee at the start. In applications where the coffee extract is spray dried, the enhanced coffee solids concentration is particularly important for preserving the fragrant coffee aroma in the final soluble coffee product, since dilute coffee extracts are generally subjected to substantial downstream concentration, eg evaporation, before drying. This is because it requires concentration. Such downstream concentration typically results in significant loss and / or degradation of the aromatic coffee aroma, which loss and / or degradation can generally be avoided by the process of the present invention. Thus, it has been found that the high concentration compulsory solids of the present invention are much more necessary and desirable for maintaining flavor in soluble coffee processing, and that soluble coffee products with good sensory water soluble quality are produced.

In situations where dilute extracts are available, the aroma of the final extract is nearly similar to the roasted powder coffee aroma at the time of departure compared to conventional extracts using multi-column extractions, and the aromas are balanced. In addition to maintaining the yield, the quality of the coffee extract is substantially improved.

The extraction yield, ie the weight of soluble coffee solids extracted per input weight of the roasted ground powder coffee, quantifies the degree of coffee extraction. In the present invention, extraction yield is better than conventional extraction devices at equivalent operating parameters. Yields generally depend on the appearance flow rate of the extract through the bed of roasted powder coffee, the residence time of the coffee in the extraction vessel, the temperature of the extract (as described below) and the total weight of extract water per weight of roasted powder coffee injected. Extract means liquid flowing through the container, which is supplied as extract water, and gradually becomes rich in soluble coffee solids until taken out from the container as a coffee extract. The apparent flow rate of the liquid and the amount of liquid supplied through the roasted powder coffee contained in the elongate column are related to the degree of extraction and washing of the coffee. Lower appearance flow rates increase the residence time of the liquid in the column and are typically advantageous for more extraction. At atmospheric extraction conditions, ie 70-100 ° C., higher apparent flow rates require longer extraction vessels to achieve the same degree of extraction, but provide better cleaning (and yield) from coffee particles.

In conditions where extraction is carried out at super-air conditions (hydrolysis conditions) of 100 to 180 ° C., a higher appearance flow rate is preferred, since a shorter liquid residence time is advantageous to prevent fragrance degradation.

Appearance flow rates of 0.03 to 0/3 m / min are convenient for use in the process of the present invention, and rates of 0.03 to 0.15 m / min are preferred to produce extracts that can be largely atmospheric atmospheric solids. The speed of 0.06 to 0/15 m / min was found to be most preferred. Appearance of 0.15 to 0.30 m / min for hydrolysis conditions or higher roast yields (23-50% roast yield), as higher speeds improve the flavor balance of the extract providing product flavor close to the original roasted powder coffee Flow rate is preferred. Of course, the apparent flow rate outside the above range may be used although the extraction efficiency is correspondingly reduced at low speeds and the extract is diluted much at high speeds.

The total weight of extract water per weight of roasted powdered coffee injected to produce a higher concentration of extract than conventional extraction is maintained similarly as in conventional extraction, ie, from about 15: 1 to 40: 1. This means flowing 6.8 to 18 kg (15 to 40 pounds) of extract liquid through 453.6 g (1 pound) of roasted ground coffee in the extraction vessel. In order to produce an excellent extract aroma in hydrolysis conditions where a faster appearance flow rate is used, it is desirable that the extraction water per weight of the roasted ground coffee to be put is maintained between 40: 1 and 90: 1.

It is also desirable to maintain the residence time of the roasted powdered coffee in the extraction vessel, another operating variable for achieving yield, similarly as in conventional extraction, ie, about 75 to 240 minutes, usually 90 to 240 minutes. A powder residence time of 90 to 140 minutes usually produces a good aroma with a profile close to the roasted powder coffee on departure, and a residence time of 140 to 240 minutes helps to produce a high concentration of aromatic extract. By setting the residence time as described above and discharging a portion of the extracted roasted powdered coffee intermittently, the number of periodic inputs and discharges of the roasted powdered coffee is fixed. This is because multiplying the fraction of the extraction vessel with intermittent discharge by the total residence time is necessarily equal to the interval between input and discharge. For example, if the total residence time is chosen to be 200 minutes and about 12.5% of the column height is intermittently discharged, the interval between periodic operations will be 25 minutes. The end result is to provide the equivalent of an eight column countercurrent extraction unit with a single extraction vessel, eliminating the complexity of the apparatus.

As described above, hydrolysis of the coffee takes place in a column where the extract water is fed to a conventional apparatus, and extraction under air occurs in a column comprising fresh roasted powder coffee which draws the coffee extract therefrom. The roasted powder coffee extraction method of the present invention provides increased adaptability as a result achieved depending on the temperature at which the extract water is supplied to the extraction vessel. In a first embodiment, subatmospheric extraction of roasted powdered coffee is accomplished by feeding extract water to the vessel at a temperature of about 70-100 ° C. and maintaining the temperature over the total height of the column. The pressure in the extraction vessel is usually at or slightly above atmospheric pressure. The intermittently extracted roasted powdered coffee may then be placed in another extraction vessel to hydrolyze the coffee and extract the remaining available soluble coffee solids produced thereby. In a second embodiment, hydrolysis is accomplished by feeding the extraction vessel to the extraction vessel at a temperature of at least 100 ° C and up to about 232 ° C. The temperature can be maintained over the entire height of the container, for example, by insulating or jacketing the container, or can be reduced through normal heat loss or by reducing the jacket temperature of the container. The pressure in the column is considerably higher than atmospheric pressure and at least coincides with the saturation pressure of the water at the selected temperature. Blow cases or other suitable devices for injecting and dispensing coffee under appropriate pressure should, of course, be used.

In a second embodiment, the process of the invention can be varied to provide both subatmospheric extraction and hydrolysis in a single extraction vessel. Extracted water is fed to the vessel at a temperature above 100 ° C. to induce moderate mild hydrolysis in the roasted powdered coffee from which the active ingredient, which is first contacted with water, is extracted the most. The temperature in the vessel is then gradually lowered by purifying the coolant through the vessel jacket or by heat loss such that the temperature can reach about 70-100 ° C. when the extract reaches the freshest roasted powder coffee at the opposite end of the extraction vessel. have. In this way, the coffee extracted at the lowest temperature is extracted under air, and the coffee with the most active ingredient is extracted at the highest temperature in the same way as in conventional extraction systems. Although the work is less complicated in this way, experience shows that accurate temperature control in a single extraction vessel is often difficult to achieve.

After atmospheric extraction in a single vessel, the countercurrent device followed by hydrolysis in a second extraction vessel or even a fixed bed is more flexible, in particular where most coffee flavors and aromas are extracted under atmospheric, so the hydrolysis operation is hot This is because it works in and is not limited by the flavor consideration.

Although the process is not strictly continuous, the present invention is certainly almost continuous than a countercurrent extraction device, since the flow of the extract is intermittently, even for a short period of time, preferably within minutes, and not at all if conditions permit. By near continuous operation, it can be much closer to steady state conditions, so that the extracted extract has a more uniform concentration profile than the extract taken from the countercurrent device. The concentration profile can be made even more uniform by preheating the roasted powdered coffee prior to introducing the roasted powdered coffee into the extraction vessel. Dried roasted powdered coffee will absorb the original weight of the extract almost as moisture, so when such coffee is placed in an extraction container, the coffee preferentially absorbs water from the initially contacted extract, concentrating the liquid and concentrating Will impair the profile. Thus, the roasted powdered coffee can be preheated to 35 to 60% by weight before being put into the extraction container. It is useful to use extracts for preliminary preparation because the extracts tend to add a coffee solids to the roasted powdered coffee to substantially increase the equilibrium concentration of the extracted extract. Preheating can be carried out with a coffee extract with water or coffee solids of 10% by weight. Regardless of the liquid used for the preparation, as described above, the preparation also helps to determine the percentage of unextracted roasted powdered coffee that is intermittently introduced into the extraction vessel.

Increasing the concentration of the extracted extract of the present invention is essential to one mode of operation of the present invention. If all other processing conditions are the same, the opportunity to produce very fragrant coffee extracts with the characteristic aroma of the original roasted powdered beans in equal or higher concentrations or yields is equally important. In particular, when the roasted powdered coffee is preliminary with the coffee extract as described above, the concentration range can be increased to about 55% by weight when the extract is discharged from the extraction vessel.

In the first embodiment described above where only sub-atmosphere extraction takes place in the extraction vessel or higher concentrations are required under hydrolysis conditions using an apparent flow rate of 0.03 to 0.15 m / min, the outlet concentration is generally about coffee solids. At least 10% by weight, typically at least about 20% by weight, preferably at least about 30% by weight and most preferably at least about 40% by weight. Higher outlet concentrations can be achieved at the same coffee-to-water ratio as used in conventional extraction apparatus operated at the same conditions. Similarly, in the same extraction vessel, in the case of atmospheric extraction and adequate hydrolysis at high coffee-to-water ratios and high draw factors (and usually short powder residence times of 75-140 minutes) and only in the case of hydrolysis, The outlet extract concentration is generally at least about 5%, for example at least 4%, typically at least 10%.

The advantage of this increased outlet concentration is realized in terms of downstream processing efficiency, cost savings, and odor improvement. Typically, the coffee extract is subjected to a substantial concentration step, generally evaporation, before drying. The concentration step is energy intensive and generally results in a significant loss of aromatic coffee fragrance with the evaporated aqueous phase. As a method of recovering some of these aromatic fragrances, for example, condensation, distillation and adsorption are known, but these methods are capital intensive and energy intensive and are not 100% successful.

The present invention provides that, in terms of both energy and aroma retention, coffee extracts are produced with high concentrations and high and balanced levels of coffee fragrances that require limited concentration downstream, or preferably do not require concentration, to be suitable for efficient drying. It is very preferable to the conventional system in this respect.

The following examples are intended to illustrate certain embodiments of the present invention. The examples do not limit the invention beyond what is claimed in the claims.

Example 1

1. For comparative purposes, 0.25 m in diameter and 5.5 in height. A countercurrent fixed bed extraction device (reflux device) with six columns, each with 82 kg of roasted powder coffee, m, was operated after equilibration was obtained. The cycle time was about 35 minutes per cycle for the total residence time of the coffee in the apparatus of about 175 minutes. The sixth column is a rotary column that drains and replaces coffee, so that five of the six columns always brew coffee. Extracted water was fed to the apparatus at about 130 ° C. to perform extraction under air as well as mild thermal hydrolysis. The total weight ratio of extract water per weight of roasted powdered coffee was 29.6: 1.

The resulting extract had about 6.7% by weight soluble coffee solids. The total yield of roasted ground coffee was about 28% by weight on a dry basis.

2. A vertical, cylindrical elongate column with 44 kg of roasted powder coffee, 0.1 m in diameter and 15.2 m in height, was used. In the steel column, two 10cm ball valves were fitted at both ends for the input and discharge of coffee. The hopper was settled on the collar so as to be connected to the column described above via a ball valve. An additional cylindrical length, representing about 12.5% of the column volume, was set vertically below the column as a brow case and connected to the column via the lower ball valve. A third 10 cm ball valve was mounted below the blow case. Water was pumped to the column through a heat exchanger and through a flow distributor such as a bayonet settled slightly above the bottom of the column. The coffee extract was taken out through a bayonet settled slightly below the top of the column. The extract was pumped from the extraction column into the tank. Roasted powdered coffee was placed in a hopper and premixed by manually mixing with the liquid. The bottom ball valve on the blow case was closed to stop the flow into and out of the column. The ball valves at both ends of the column were opened essentially simultaneously, allowing gravity roasted powder coffee to fill the column and the extracted coffee to fill the blow case, then closing both valves. The flow into and out of the column was then resumed. The blow case contents were cooled and the blow case was emptied by opening the bottom ball valve.

In the first run (Run 1), approximately 12.5% of the volume of coffee in the column was intermittently drained into a conventional blow case at the bottom of the column every 25 minutes for a total residence time in a 200 minute container, with 58% by weight of moisture. An equal volume of unextracted roasted ground coffee preliminary with water was introduced to the top of the column through a blow case located at the top of the column. Extraction water was supplied to the bottom of the column at about 88 ℃, extraction was performed under the air. The total weight ratio of water supplied per weight of roasted powdered coffee was 29.6: 1.

The resulting extract had soluble solids at a concentration of about 13.8% by weight. The total dry yield of roasted powdered coffee was 23% by weight.

Run 2 was carried out under the same conditions, except that the roasted powdered coffee was preliminary with a portion of the coffee extract taken from the top of the column to adjust the water supplied to replenish the water contained in the pre-extracted extract. . The concentration of the resulting extract was 36.6 wt% of soluble solids. Simple preliminary methods using extracts increased concentrations almost threefold compared to the first run.

A third run (Run 3) was carried out on the column of the same overall shape as in runs 1 and 2 of Example 2, the backflow device of this example having a diameter of 0.25 m, a height of 7.9 m and 140 kg of roasted powder coffee Holds. The conditions were similar to those in the countercurrent apparatus, except that the ratio of water fed per weight of roasted powdered coffee was further increased to about 76: 1 and the temperature of the extract water was reduced to about 120 ° C.

The extract of Run 3 was closest to the aroma of roasted powdered coffee at Run 1-3 of Example 2 or at the start of this Example, which again was unachievable in conventional fixed bed percolators. It demonstrates the increased efficiency of the present invention in the ratio of coffee to coffee. The results are shown in Table 1 below.

Increasing the ratio of water per weight of roasted powdered coffee as development 3, it is readily seen to reduce the temperature required to achieve the same yield and also the extraction residence time in the extractor. This, in turn, further reduces the production of undesirable decomposed fragrance (furfural), but improves the extraction efficiency of preferred fragrances such as methyl furan, 2-3-pentanedione and diacetyl. An additional advantage is that the increase in the ratio of water per roasted powder coffee weight can be easily achieved without being limited to the pressure drop imparted by the complex manifold in conventional fixed bed extraction devices.

Although the coffee extracted in the countercurrent device has a slightly higher yield than 2 for Run 1 and Run 2, this is due to the high extraction temperature of the method, which is necessary because of device limitations. The higher efficiency of the present invention can be seen at higher concentrations of the extract produced by the method, which concentration is conventionally produced in the first case, despite the use of the same weight of water for the coffee weight in each method. Almost twice the concentration of the extract. When the recycle extraction technique was used, the concentration increased by 6 times. Higher concentration extracts are advantageous in that high concentration extracts have more aroma, and the extract needs less concentration before drying, thus requiring less equipment and operating costs.

Example 2

1. In a second comparative example, a countercurrent fixed bed extraction device (first fixed bed) having six columns filled with 82 kg of roasted powder coffee, each 0.25 m in diameter and 5.2 m high, was equilibrated and operated. . The cycle time was about 32 minutes in 5 columns for any time strum (the sixth column was emptied and refilled) to give a total residence time of 160 minutes. Extracted water was fed to the apparatus at about 177 ° C. (about 350 ° F.) to perform sub-air extraction as well as some thermal hydrolysis. The total weight of water per roasted powdered coffee weight was 15: 1.

The total yield of roasted ground coffee on a dry basis was about 38% by weight, which gave the extract a soluble coffee solids concentration of about 23.8% by weight.

2. A vertical, cylindrical elongate column with approximately 227 kg of roasted powder coffee, similar in overall form to the column of Example 1, 0.25 m in diameter and 13.6 m in height, was used. In the steel column, two 10 cm ball valves were fitted at both ends to feed and discharge coffee. The vessel was settled on the column, connected to the column via a ball valve, and a second vessel, about 10% of the column volume, was settled vertically below the column and connected to the column through the lower ball valve. This lower container acts as a blow case, which includes a third 10 cm ball valve at the lower end.

Water was pumped to the column through a heat exchanger and through a flow distributor such as a bayonet settled slightly above the column bottom. The coffee extract was taken out through a bayonet settled slightly below the top of the column and pumped into a tank.

Roasted powdered coffee was fed to the upper vessel without preheating, and the vessel was separated and then compressed using about 10 bar of air. In this case, the flow into and out of the column was not interrupted. The ball valves on both ends of the column were opened essentially simultaneously to fill the column with roasted powder coffee under the influence of air overpressure, and the extracted coffee to fill the blow case, with both valves closed, while the contents of the blow case The blow case was discharged by compression, and then the blow case lowermost valve was opened to transfer the powder and water extracted with the most active ingredient to the powder treatment hopper with the most active ingredient extracted.

In the first run (Run 1), 10% of the coffee volume in the column was drained to the blow case every 10 minutes for a total residence time of about 100 minutes in the container. An equal volume of unextracted roasted powdered coffee was then charged to the top of the column through a fill container. Extracted water was fed to the bottom of the column at a temperature of about 160 ° C. (about 320 ° F.) to perform extraction under air and mild hydrolysis of the roasted ground coffee. The total weight ratio of feed water per weight of roasted powdered coffee was 31: 1.

The resulting extract had soluble solids at a concentration of about 22.4% by weight. The total dry yield of roasted powdered coffee was about 38% by weight.

Run 2 was run on the same column as run 1. In this development, conditions 1 and 1 were increased except that the total weight ratio of feed water per weight of roasted powdered coffee was increased to 53: 1 and the temperature of the extract water was reduced to about 149 ° C. (about 300 ° F). Same. The resulting extract had a soluble solids concentration of about 10% by weight and the overall dry basis yield of roasted powdered coffee was about 40% by weight.

Extraction of the second fixed bed (second fixed bed) was carried out with a higher extraction factor compared to development 2.

Subsequently, the four extracts obtained from the fixed bed extraction apparatus development of this example and the two developments (Run 1, Run2) from the pulsed elongate column were analyzed by gas chromatography.

The fragrance results herein were obtained by using purge and trap gas chromatography. The aroma recovery value was determined by G.C. Derived by assigning the G.C. number of the extract to the number (corrected or extracted yield) and multiplying by 100.

The operating conditions and the results of the GC analysis are shown in Table 2 below.

While essentially the same extraction yields are obtained in developments 1, 2 and the first fixed bed summarized in Table 2, it is understood that the coffee extract has an aroma balance closer to the aroma of roasted powdered coffee at the start by an embodiment of the present invention. It is easy to see. Directly comparing the data from development 1 with the data from the first fixed bed extraction unit, the coffee extracts in the extract water temperature and the powder dwelling bed will have a more severe time in order to achieve the same extraction yield as in this method with essentially the same extraction concentration. Receive temperature exposure.

The benefits of the greater extraction efficiency of the present invention can be understood by studying the gas chromatography of Table 2. In run 1, the product concentration of furfural is 1/3 of the fixed bed extractor. Furfural is commonly used as an indicator of flavor breakdown in coffee processing. Secondly, the total G.C. numbers are the same, which shows a good balance in terms of desirable fragrance over undesirable furfural. In addition, the extraction efficiency of the preferred coffee aroma, such as 2-methyl furan and 2-3-pentanedione, by the process of the invention is equal to or better than conventional fixed bed extraction. Thus, with this great efficiency the extract has a fragrance balance close to that of roasted powdered coffee at the start.

Comparing developments 1 and 2 of the present invention in Table 2, further increasing the ratio of water per weight of roasted powdered coffee in development 2 reduced the temperature required to achieve the same yield and also the extraction residence time in the extractor. Able to know. This, in turn, reduces the production of undesirable decomposition products, as evidenced by low furfural concentrations, but further improves the extraction efficiency of preferred fragrances such as 2-methylfuran and 2,3-pentanedione. An additional advantage of the present invention is that it can be achieved without limiting the pressure drop added by the complex manifold in conventional fixed bed extraction devices by increasing the ratio of water per weight of roasted powdered coffee.

Claims (17)

(a) by supplying the extraction water to the bottom of the elongated vertical column extraction container containing the roasted powder coffee extracted the most solids, the most solids extracted coffee as performed by countercurrent extraction system to the highest of 232 ℃ Extracting at the extraction water temperature; (b) the extraction water flowing at an external flow rate of 0.03 to 0.3 m / min at a temperature of 70 to 232 ° C., reduced during extraction or maintained constant throughout the column, with the extracted roasted powdered coffee almost continuously In a countercurrent manner, contacting for 75 to 240 minutes such that the final extraction concentration is between 5 and 55 weight 5 of coffee solids; (c) withdrawing the coffee extract from the upper end of the container; (d) intermittently discharging 4-20% by volume of the extracted roasted powdered coffee containing feed water in the bottom of the extraction vessel into the lower blow case; And (e) performing step (d) simultaneously with intermittently adding fresh coffee to the top of the extractor and discharging the coffee and wash water from which the solids are most extracted from the bottom of the extractor, in a substantially continuous countercurrent manner, 1/2 volume of unextracted dry roasted powdered coffee or approximately equal volume of pre-wetted roasted powdered coffee to the extraction column from the upper blow case was introduced from the upper blow case A method of extracting roasted powdered coffee for producing a highly aromatic coffee extract in close proximity to the first roasted powdered coffee, comprising the steps of: 2. The method of claim 1, further comprising stopping the introduction and discharge of liquid into the brewing vessel during the period of injecting and discharging the coffee. The process of claim 1 wherein the extraction vessel is a vertically elongated column having a length of 7.5 to 23.0 m and a diameter such that the apparent flow rate is from 0/03 to 0.3 m / min, and the flow of extraction water is continuous. . The method of claim 1, further comprising pre-wetting the unextracted roasted ground coffee to a wet state of 35 to 60% by weight prior to entering the extraction container. 5. The method of claim 4, wherein the previously extracted roasted powdered coffee is wetted with water. 5. The method of claim 4, wherein the coffee extract is previously wetted with unextracted roasted powdered coffee. The method of claim 1, wherein the appearance flow rate is maintained at 0.06 to 0.15 m / min and the temperature of the extraction water is maintained at 70 to 232 ℃ to obtain a final extract concentration of 10 to 55% by weight of the coffee solids, the same coffee is A method characterized by obtaining a higher solids concentration than obtained by the multiple column, countercurrent extraction method. The method of claim 1, wherein the appearance flow rate is maintained at 0.15 to 0.30 m / min and the temperature of the extraction water is maintained at 70 to 180 ° C., which is used in the extraction of the invention, substantially improved over coffee extracted by conventional methods. Obtaining a final extract concentration of at least 4%, preferably at least 10%, with a balance of aroma and aroma close to the unextracted roasted powdered coffee. 8. A method according to claim 7, characterized in that the extraction water is fed to the extraction vessel at a temperature of 70 to 180 ° C. 10. The method of claim 9, wherein the temperature in the extraction vessel is maintained between 70 and 100 ° C. The method of claim 1, wherein the extraction water is fed to an extraction vessel, maintained at a temperature of 70-180 ° C. in the extraction vessel, and the concentration of the extraction water is increased to 10-55 wt%. A method according to claim 1, characterized in that the extraction water is fed to the extraction vessel at a temperature of 100 to 180 [deg.] C. to reduce the temperature according to the height of the vessel. The roasted powdered coffee of claim 1, wherein the extraction water is fed to the extraction vessel at a temperature of 100 to 180 ° C. to hydrolyze the coffee at the bottom of the extraction vessel, and the temperature is lowered to 70 to 100 ° C. at the top of the column. Air extraction. The method of claim 1, further comprising the step of extracting the roasted powdered coffee in the extraction vessel of claim 1 under air, followed by hydrolysis of the intermittently discharged fraction of the roasted powdered coffee in a countercurrent fixed bed extraction device. Including method. The method of claim 1, wherein the extracted roasted powdered coffee is discharged into the blow case, and the unextracted roasted powdered coffee is injected into the extraction container, wherein the blow case is pressurized to a pressure slightly higher than the pressure in the extraction container. Further comprising. 8. The method of claim 7, wherein the temperature of the extract water is from 70 to 180 ° C and the ratio of water to coffee is from 15: 1 to 40: 1. The method of claim 8 wherein the ratio of water to coffee is from 40: 1 to 9: 1.