GB2565872A

GB2565872A - Container with effervescent action

Info

Publication number: GB2565872A
Application number: GB1806462.6A
Authority: GB
Inventors: Queste Mathieu
Original assignee: Arc France SAS
Current assignee: Arc France SAS
Priority date: 2017-04-21
Filing date: 2018-04-20
Publication date: 2019-02-27
Anticipated expiration: 2038-04-20
Also published as: FR3065360A1; FR3065360B1; GB2565872B; GB201806462D0

Abstract

A carbonated beverage container 1 comprises an impermeable wall 5 made of at least one material. The wall defines an inner surface which comprises a region covered with a hydrophobic coating 7. A plurality of discontinuities 9 are produced in the hydrophobic coating, said discontinuities not opening into the impermeable wall. The hydrophobic coating may be a film and may comprise an organometallic compound and/or polysilazane. The discontinuities may have a depth less than the depth of the hydrophobic coating. A method suitable for creating nucleation sites on the inside of a beverage container so as to promote the formation of bubbles in contact with the carbonated beverage is also disclosed. Perforations 8, such as blind holes, may be produced in the hydrophobic coating by laser shots. Discontinuities, such as cracks, may then spread into the coating.

Description

Container with effervescent action

The invention relates to the field of liquid containers, and more particularly articles of glassware.

During the production of beverage containers such as glass tumblers, the surfaces created are generally made as smooth as possible, particularly in order to give them good transparency and for aesthetic reasons.

The service of a sparkling beverage in a container generates effervescent phenomena, or bubbling, and the accumulation of foam on the surface. For the service of beer or sparking wine, for example, it is desirable to generate and maintain effervescence. The zones in which bubbles form in a glass are called nucleation sites.

It has been observed that the presence of irregularities in container surfaces in contact with a sparkling beverage increases the concentration of dissolved gas in the beverage and the emergence of bubbles. In order to encourage bubbling, inner surfaces having a rough relief were created in containers. When the container is filled with a carbonated liquid such as a sparkling beverage, rough areas on the inner surface trap pockets of air. The interfaces between the liquid and the air pockets enable better gas exchanges. The rough areas thus form nucleation zones.

European EP 0 703 743 in the name of Charles Glassware describes a method for applying a material to a surface in order to create nucleation sites and improve bubbling. Browning was sometimes observed at the bottom of the glass. French patent application FR2 531 891 filed on 16 August 1983 describes a method for ablating a material that promotes the creation of a gas release zone. Exemplary applications are given in the international application WO 2010/048488 filed on 23 October 2009.

French patent FR 3 008 295 proposes creating nucleation sites on the inside of a beverage container by means of surface irregularities in a selected region of the container onto which a hydrophobic layer is then deposited in the selected region.

The Applicant has identified the need to further improve the quality of the bubbling in order to appeal to larger markets with beer types having lower alcohol content and/or a lower dissolved carbon dioxide content.

Prof. Liger-Belair and his team at UMR CNRS 7331 - University of Reims Champagne-Ardenne have published the following articles on effervescence:

Liger-Belair, G. “The physics behind the fizz in champagne and sparkling wines,” European Physical Journal: Special Topics 201, 1-88, 2012.

Liger-Belair, G. “The physics of champagne bubbles \La physique des bulles de champagne]” Annales de Physique (Paris) 27 (4), 1-106, 2002.

Liger-Belair, G.; Conreux, A.; Villaume, S.; Cilindre, C. “Monitoring the losses of dissolved carbon dioxide from laser-etched champagne glasses” Food Research International, 54, 516-522, 2013.

Liger-Belair, G.; Voisin, C.; Jeandet, P. “Modeling non-classical heterogeneous bubble nucleation from cellulose fibers: Application to bubbling in carbonated beverages” Journal of Physical Chemistry B 109, 14573-14580, 2005.

Liger-Belair, G.; Parmentier, M.; Jeandet, P. “Modeling the kinetics of bubble nucleation in champagne and carbonated beverages” Journal of Physical Chemistry B 110, 21145-21151, 2006.

Liger-Belair, G. “How many bubbles in your glass of bubbly?” Journal of Physical Chemistry B 118, 3156-3163, 2014.

Liger-Belair, G.; Bourget, M.; Villaume, S.; Jeandet, P.; Pron, H.; Polidori, G. “On the losses of dissolved CO2 during champagne serving” Journal of Agricultural and Food Chemistry 58, 8768-8775, 2010.

It is desirable to have a beer drinking container that ensures bubbling that is both satisfactory for a large number of the beer types it contains, and stable throughout the use of the container.

The invention improves the situation.

The applicant proposes a carbonated beverage container, particularly made of glass, comprising an impermeable wall made of at least one structural material defining an inner surface for receiving a beverage, said inner surface comprising a region covered with a hydrophobic coating, a plurality of discontinuities being provided in said region, said discontinuities not opening into the impermeable wall and mostly not penetrating the hydrophobic coating.

The discontinuities are formed from the hydrophobic coating. The discontinuities form stable nucleation sites. The wash resistance is excellent, notably greater than 500 glass washer cycles.

The Applicant has identified both a need to preserve the foam for a longer time once the beer is dispensed in order to increase the customer’s enjoyment, and a need to obtain equivalent foam in a dry glass at room temperature and in a wet, warm glass, particularly one emerging from a glass washer.

The Applicant noticed that the container it developed had improved bubbling properties when the container was in a warm, wet state. In this context, the words warm and wet indicate the state in which a container emerges from a glass washer.

In one embodiment, the hydrophobic coating is a film. The hydrophobic film may have an even thickness. The hydrophobic film can be deposited by means of a depositing technique such as for example spraying, particularly ultrasound assisted. The hydrophobic film can be deposited uniformly.

In one embodiment, the hydrophobic coating has a thickness between 1 and 100 pm, preferably between 5 and 50 pm, and more preferably between 7 and 14 pm. If too thin, the hydrophobic coating would have too high a proportion of discontinuities passing through said hydrophobic coating. If too thick, the hydrophobic coating would run the risk of having a coloration. The preferred hydrophobic coating is transparent, or at least translucent.

Preferably, the hydrophobic coating comprises an organometallic compound.

In one embodiment, the hydrophobic coating comprises a polysilazane, preferably organic, for example DURAZANE® 1800 from AZ Electronic Materials or DURAZANE® 1500. The polysilazane can be treated at a sufficient temperature. The hydrophobic coating withstands a number of wash cycles far greater than 500.

In one embodiment, the hydrophobic coating withstands heat treatment at over

600°C. The hydrophobic coating is capable of being heated locally during the creation of the discontinuities.

In one embodiment, the discontinuities have a depth smaller than the thickness of the hydrophobic coating.

In one embodiment, the discontinuities have a depth between 1 and 80 pm, preferably between 1 and 40 pm, and more preferably between 1 and 10 pm.

In one embodiment, the discontinuities have a width between 0.5 and 2 pm.

In one embodiment, the discontinuities have a length between 1 and 300 pm, and preferably between 75 and 200 pm.

In one embodiment, the discontinuities have a length per unit of surface area of the hydrophobic coating between 0.11m'¹ and 0.28 m'¹ (for example with a diameter of the hydrophobic surface of 3 cm).

In one embodiment, the container comprises perforations having a diameter between 50 and 300 pm, and preferably between 100 and 200 pm.

In one embodiment, the perforations have a diameter-to-depth ratio between 2 and 4, and preferably between 2.5 and 3.5.

In one embodiment, the discontinuities result from perforations produced in the hydrophobic coating. The discontinuities can have the appearance of cracks caused by the perforations and/or connected to the perforations. The discontinuities thus have a random design based on a predetermined pattern of perforations.

In one embodiment, the discontinuities have a predetermined design. The discontinuities can have the appearance of a reproducible pattern, for example a grid. The grid may be present in the absence of said perforations. The grid may be present along with said perforations, either juxtaposed or intersecting.

In one embodiment, a method is provided for creating nucleation sites on the inside of a beverage container and promoting the formation of bubbles in contact with a carbonated beverage wherein:

- a region is coated with at least one hydrophobic layer, the container comprising an impermeable wall made of at least one structural material defining an inner surface for receiving the beverage, said inner surface comprising said region, and

- discontinuities are produced in said region, said discontinuities not opening into the impermeable wall and mostly not penetrating the hydrophobic coating.

In one embodiment, said at least one hydrophobic layer is deposited by spraying and then heat treated. The hydrophobic film can be heat treated at a temperature greater than 100°C, preferably 150°C, and more preferably 175°C. The duration of the heat treatment is tied to the temperature. The duration of the heat treatment can be from 8 to 12 hours at room temperature, 2 to 3 hours between 70 and 100°C, 40 to 80 minutes between 130 and 180°C, and 1 to 10 minutes between 200 and 300°C. The hydrophobic coating in the final state is suitable for contact with food. The final state is obtainable by means of heat treatment.

In one embodiment, the discontinuities are formed by the application of a line laser beam. The lines of discontinuity can be unbroken or broken. The lines of discontinuity can have a reproducible pattern.

In one embodiment, the discontinuities are formed by the application of a dot laser beam. The applied dots of the laser beam cause cracking in the hydrophobic layer. Said cracks can emanate from the applied dots. Said cracks form discontinuities.

In one embodiment, the laser beam has a power between 10 and 500 W, a frequency between 1 and 20 kHz, and a movement speed between 1 and 10 m/s, for example a power of 100 W, a frequency of 5 kHz and a speed of 5 m/s.

The container can also comprise a glass body. Transparency makes it possible to see the bubbles appear and make their way from the nucleation site to the surface of the beverage.

Other features, details and advantages of the invention will emerge from the reading of the following detailed description, and from the attached drawings, in which:

- Fig. 1 is a cutaway view of a container;

- Fig. 2 a view of a detail of Fig. 1;

- Fig. 3 is a partial top view of the container of Fig. 1;

- Fig. 4 is a view similar to Fig. 1, in the presence of a carbonated beverage;

and

- Fig. 5 is a view of a detail showing the birth of a bubble.

The drawings and the description below essentially contain elements that are certain in nature. They can therefore not only facilitate understanding of the present invention, but also contribute to its definition, if necessary.

In a liquid food, the carbon dioxide (CO2) dissolved in the liquid phase is the carrier gas for the effervescence phenomenon. The frequency at which bubbles are emitted during drinking, the expansion of the bubbles in the container, and the number of bubbles likely to be formed are tied to a certain number of physicochemical parameters of the liquid phase and of the container from which one is drinking.

When a gas is placed in contact with a liquid, a part of this gas is dissolved in the liquid. Various factors influence the solubility of the gas in the liquid, particularly the temperature and the pressure. At equilibrium, there is proportionality between the concentration of a chemical species i, notated ci, in the liquid phase and its partial pressure in the gas phase Pi. Henry’s Law states:

Ci = k_HPi [1]

The proportionality constant k_H is known as the Henry’s Law constant. It is strongly dependent on the gas and the liquid in question, as well as the temperature.

Under the normal atmospheric pressure P_o ~ 1 bar, given the solubility of CO2 in a beer at 4 °C, which is equal to k_H ~ 2.6 g/L/bar, said beer is capable of dissolving about 2.6 g/L of CO2.

When a chemical substance i is at equilibrium on either side of a gas/liquid interface, its concentration in the liquid verifies Henry’s Law. We then say that the liquid is saturated with respect to this substance. Specifically, saturation indicates equilibrium.

When the concentration ci of a chemical substance i in a liquid is greater than that predicted by Henry’s Law, the liquid is supersaturated with respect to this substance. In order to quantify this out-of-equilibrium situation, we define the sup er saturation coefficient Si as the relative excess concentration in a liquid of a substance i compared to the reference concentration, notated co (chosen as the concentration of equilibrium of this substance under a partial pressure equal to the prevailing pressure in the liquid Pl). We therefore define the supersaturation coefficient Si as follows:

Si = (ci-co)/c_o [2]

When a liquid is saturated with respect to a chemical substance, we have Si > 0. The liquid releases part of its content of this chemical substance in order to reach a new state of equilibrium that verifies Henry’s Law.

Under drinking conditions, in a container, the prevailing pressure in the liquid is nearly identical to the ambient pressure. Given the low height of the liquid, which does not exceed 10 to 15 cm, the effect of the excess hydrostatic pressure that prevails at the bottom of the container is negligible relative to the atmospheric pressure. At a temperature of 4 °C, we can therefore deduce that its concentration at equilibrium is equal to:

co = k_HP_L « k_HPo « 2.6 g/L [3]

Not all beers have the same concentration of dissolved CO2. Some are lightly charged to a level of 3-4 g/L, while others are heavily charged, up to 7-8 g/L. Their respective supersaturation coefficients with respect to the dissolved CO2 are therefore not the same. In the case of an average beer, carbonated to about 5 g/L, its sup er saturation coefficient (a 4 °C) using equation [2] is:

S_CO2 = (ci-c_o)/co « (5-2.6)/2.6 « 0.9 [4]

For comparison (again at 4 °C), strongly sparkling waters (like Badoit Red) have sup er saturation coefficients on the order of 1.3, while champagnes (while still young) have much higher coefficients, on the order of 3.4. In general, the higher the sup er saturation coefficient of a liquid charged with dissolved CO2, the more intense the resulting kinetics of release of the dissolved carbon dioxide will be in order to reestablish Henry’s equilibrium. However, it has been observed that the supersaturation of a liquid with dissolved gas is not necessarily synonymous with bubble formation and thus, effervescence.

In fact, at the supersaturation values of beers, the formation of bubbles requires the presence of gas pockets in the medium whose radius of curvature rc exceeds a socalled critical value, defined as follows:

r_c = 2 γ/PoS [5] where γ is the surface tension of the liquid, P_o is the ambient pressure and S is the CO2 supersaturation coefficient of the liquid phase.

At the normal atmospheric pressure of 1 bar and at 4 °C, in the case of a beer whose surface tension is typically equal to 45 mN/m and whose supersaturation coefficient is about 0.9, the above equation reveals a critical radius on the order of 1 pm below which bubble formation does not happen.

In order to make CO2 bubbles appear and expand in a beer, the medium contains internal gas microbubbles whose radii are larger than this critical radius on the order of 1 pm. This is referred to as non-standard heterogeneous nucleation (as opposed to the so-called standard nucleations, which involve the spontaneous formation, from nothing, of bubbles in a strongly supersaturated liquid). Standard nucleations require very high dissolved gas supersaturation coefficients (>100), which are incompatible with sparkling beverages.

This raises the question of the origin of the gas nuclei that are the catalysts for effervescence in a container.

The Applicant observed, in situ, the manner in which bubbles appeared in beers served in smooth glasses not subjected to any particular treatment. In the great majority of cases, air pockets trapped inside particles adsorbed on the surface of the glass play the role of a nucleation site. The radius of these gas pockets trapped inside the particles (most often cellulose fibers) generally exceeds the critical radius required to allow the release of dissolved CO2 and hence the repetitive production of bubbles in the glass.

The critical radius for nucleation takes into account the beer’s concentration of dissolved CO2, cf. equations [4] and [5], Yet once the beer is served, said concentration is no longer the same as that initially present. The service is a critical step. In fact, the pour into the container generates substantial turbulence, which accelerates the release of the dissolved carbon dioxide. The colder the beer, the more the dissolved carbon dioxide stays dissolved as the beer is served. In essence, beer is more viscous when it is cold. The speed of release of the dissolved CO2 from the beer is faster when the viscosity of the beer is low. Moreover, the turbulence of the pour is more effectively reduced when the beer is viscous. Consequently, the colder the beer is when served, the better the retention of the dissolved carbon dioxide as it is poured.

- For St Omer beer, served a 4 °C in a smooth glass, there are critical radii of 1.02 ± 0.02 pm.

- For Carlsberg beer, served at 4 °C in a smooth glass, there is a critical radius of 1.05 ±0.02 pm.

Furthermore, it has been established that the flow of bubbles, i.e. the number of bubbles per second, is proportional to the square of the temperature and the concentration of dissolved CO2 in the liquid, and inversely proportional to the dynamic viscosity of the liquid (in kg/m/s).

In a container according to one embodiment, the Applicant conducted tests in which the dry container at room temperature is filled with beer at 4-5°C for 10 minutes. The container is then emptied, rinsed with clear water, and placed in a glass washer.

The clean container is removed from the glass washer and filled with the volume of beer for which it is designed, in a continuous motion. The height of the foam is observed for 5 minutes after filling. The height of the foam is greater than or equal to 1 cm. The bubbling quality is observed. The foam lasts longer and the bubbling quality is improved.

The Applicant has not identified with certainty the cause of this excellent bubbling.

One hypothesis is that the discontinuities produced, at least in the hydrophobic layer, have hydrophobic properties.

This advantageously makes it possible to eliminate a material application step during production

Such a container 1 is illustrated in the figures. The container 1 here takes the form of a drinking glass. In variants, the container 1 takes the form of a pint beer glass, a champagne flute, or any other container adapted for receiving a sparkling beverage.

The method described below applies to most containers for carbonated beverages or sparkling beverages for which the control of effervescence is important, see Fig. 4.

The container 1 here is constituted by a substantially flat bottom 3 and a lateral wall 5 of substantially truncated cone shape. The container 1 here is axially symmetrical. In the example described here, the bottom 3 and the wall 5 form a singlepiece body. The body has an inner bottom surface and an inner side surface. The inner surfaces are intended to come into contact with the beverage during the use of the container.

The container 1 can be obtained by known manufacturing techniques, for example by pressing, blowing, and/or centrifuging. At the outlet, the inside of the container 1 is substantially smooth and uniform. The container 1 is said to be untreated.

In the example described below, the inner bottom surface 3 is coated. Other parts may be treated based on the desired location of the bubbles in the finished container, or only part of the bottom 3 may be treated.

In one embodiment, the coating 7 is a hydrophobic layer. The hydrophobic layer comprises polysilazane, and is preferably made of polysilazane. The choice of a short term heat treatment makes it possible to increase the retention of the carbon in the hydrophobic layer. The transformation of the polysilazane into silica is largely avoided. The thickness of the hydrophobic layer in this case is between 1 and 100 pm, preferably between 3 and 50 pm, and more preferably between 4 and 10 pm. The hydrophobic layer is deposited on the bottom surface by spraying. The spraying can be ultrasound assisted. The sprayed layer is then heat treated at 180°C for 1 hour.

Laser shots are applied to the coating 7, see Figs. 2 and 3. The laser has a power of 100 W, a frequency of 5 kHz and a movement speed of 5 m/s. The laser shot produces an ablation of the material of the coating 7, localized in blind holes 8. The blind holes 8 can have a depth on the order of 10 to 20% of the thickness of the coating

7. From the blind holes 8, cracks 9 spread into the coating 7. The width of the cracks 9 is smaller than the width of the holes 8. The depth of the cracks 9 is similar to or slightly smaller than the width of the holes 8. A crack 9 generally has one end that is attached to a hole 8.

The cracks 9 constitute discontinuities. The depth of the cracks 9 is between 1 and 10 pm. The width of the cracks 9 is about 1 pm. The length of the cracks 9 is between 75 and 200 pm. The length of the cracks 9 per unit of surface area of the hydrophobic coating is between 0.11m'¹ and 0.28 m'¹ with a diameter of the 5 hydrophobic surface of 3 cm.

The blind holes 8 constitute perforations with a diameter between 100 and 200 pm. The diameter-to-depth ratio is between 2.5 and 3.5.

Once the container 1 is filled with beer, it is observed that the bubbles form inside the beer on the edges of the holes 8 and the cracks 9.

In Fig. 5 both holes 8 and cracks 9 may be seen, along with several bubbles 10 expanding rapidly.

The invention is not limited to the exemplary methods and containers described above, which serve merely as examples, but includes all of the variants that a person of ordinary skill in the art might consider within the scope of the claims below.

Claims

1. A carbonated beverage container, particularly glass, comprising an impermeable wall made of at least one structural material defining an inner surface for receiving a beverage, said inner surface comprising a region covered with a hydrophobic coating , a plurality of discontinuities being produced in said region, said discontinuities not opening into the impermeable wall and mostly not penetrating the hydrophobic coating.

2. The carbonated beverage container according to claim 1, wherein the hydrophobic coating is a film.

3. The carbonated beverage container according to any of the preceding claims, wherein the hydrophobic coating has a thickness between 1 and 100 pm, preferably between 5 and 50 pm, and more preferably between 7 and 14 pm.

4. The carbonated beverage container according to any of the preceding claims, wherein the hydrophobic coating comprises an organometallic compound.

5. The carbonated beverage container according to any of the preceding claims, wherein the hydrophobic coating hydrophobic coating comprises a polysilazane.

6. The carbonated beverage container according to any of the preceding claims, wherein the hydrophobic coating withstands heat treatment at over 600°C.

7. The carbonated beverage container according to any of the preceding claims, wherein the discontinuities have a depth smaller than the thickness of the hydrophobic coating.

8. The carbonated beverage container according to any of the preceding claims, wherein the discontinuities have a depth between 1 and 80 pm, preferably between 1 and 40 pm, and more preferably between 1 and 10 pm.

9. The carbonated beverage container according to any of the preceding claims, comprising perforations having a diameter between 50 and 300 pm, and preferably between 100 and 200 pm, and the perforations have a diameter-to-depth ratio between 2 and 4, and preferably between 2.5 and 3.5.

10. A method for creating nucleation sites on the inside of a beverage container and promoting the formation of bubbles in contact with a carbonated beverage, wherein a region is coated with at least one hydrophobic layer, the container comprising an impermeable wall made of at least one structural material defining an inner surface for receiving the beverage, said inner surface comprising said region, and discontinuities are produced in said region, said discontinuities, said discontinuities not opening into the impermeable wall and mostly not penetrating the hydrophobic 5 coating.

11. The method according to claim 10, wherein said at least one hydrophobic layer is deposited by spraying then heat treated.

12. The method according to claim 10 or 11, wherein the laser beam has a power between 10 and 500 W, a frequency between 1 and 20 kHz, and a movement speed

10 between 1 and 10 m/s.