MXPA00010602A - Improved process for alcoholic fermentation - Google Patents

Abstract

The invention relates to a process for alcoholic fermentation, comprising the use of at least one mineral-rich or mineral-enriched yeast as a nutrient source for said fermentation.

Description

IMPROVED PROCESS FOR ALCOHOLIC FERMENTATION DESCRIPTION OF THE INVENTION The present invention relates generally to an improved process for alcoholic fermentation comprising the use of a mineral-rich or mineral-enriched yeast as a nutrient in such a fermentation process and the use of such a yeast as a nutrient. in a process of alcoholic fermentation. There are a number of minerals that are required in trace amounts for efficient alcoholic fermentation. These in particular include metals capable of altering the metabolism of the fermentation, such as the divalent metals for example manganese, magnesium and zinc. There has been increasing awareness of the importance of such trace minerals in alcoholic fermentations, particularly with respect to beer. The zinc concentration of a must is of particular importance from two perspectives. First, if it is limiting, it can lead to sub-optimal fermentations, even incomplete ones, to problems with the stability of the foam and the flocculence of the yeast. Secondly, adequate levels of zinc can help in the optimization of alcoholic fermentations, vis a vis in the production of ethanol and the uptake of sugars that are plentiful. This second perspective has a greater importance during the fermentations when the yeast is subjected to greater tensions. In addition, brewers commonly recycle the yeast from one fermentation to another. The yeast resettled from a fermentation where zinc is limiting in another beer must, which is also deficient, would exacerbate the fermentation problems. Other minerals have shown to be of importance in the course of an alcoholic fermentation. Manganese is thus known to be involved as a substitute zinc metabolism, and could possibly mitigate some toxic effects associated with high zinc concentrations. Another example is the magnesium that is reported is important for efficiency in alcohol fermentations. This is particularly a problem for the fermentation of certain substrates where there is an excess of calcium ions present. Calcium is in fact known to be an antagonist of magnesium metabolism and, for example, in beer, calcium is added deliberately in order to control the pH (acidity) and somehow activate the enzymes of the germinated barley. For most alcoholic fermentations, there is therefore a deficit of natural mineral perceived in the substrate, and the minerals, in the form of mineral salts such as zinc / manganese / magnesium chloride or sulfate, are generally added directly within the substrate, for example in the wort in the boiling stage for the production of beer. The use of such mineral salts, although relatively effective, conflicts with the desire of some industrialists to produce additive-free alcohols. Alternatives to the addition of mineral salts have therefore been proposed in previous decades. This includes preloading the fermentation yeast with a metal in such a way that the metal is barely released from the cell body of the fermentation yeast during the fermentation process (JP 63287474), or using slag trub or acid extracts from the fermentation process. used pomace or hops trub (US 4,840,802) to make use of the trace elements they contain. Although all these alternatives are, in terms of quantity and quality of the alcoholic fermentation production, at best, only substantially equivalent to the initial solution of the direct addition of the mineral salts. Its industrial application is therefore very restricted, and some of them show problems of bad odors associated with the process (for example the use of acid extract). None of the teachings of the prior art therefore provides completely satisfactory results. It is an object of the present invention to provide an improved process for alcoholic fermentation which, in addition to not showing the disadvantages of the above techniques is quantitatively, and also qualitatively, more efficient than the solution of directly added mineral salts or any other alternative solution. The process and the use according to the invention allow a growth of the yeast for improved fermentation, and accelerated fermentation. It also shows many advantages: it is very easy to handle, applies to any alcoholic fermentation process and is economically very beneficial. The process of the invention comprises the use of at least one yeast rich in minerals or enriched with minerals not as a fermentation microorganism, but as a nutrient source: the present invention in fact shows that, contrary to the wisdom received in the industry brewing, another microorganism can be added efficiently to a fermentation process without leading to microbial instability and that is also able to provide the fermentation microorganism with nutrients, and particularly with minerals such as zinc, magnesium, manganese in a very efficient. As will be further described and illustrated below, this efficiency as a source of ore lies not only in an efficient mineral flow from the yeasts used as a source of nutrients to the micro-organism of fermentation: the process and use according to with the invention they are in fact more efficient than the direct addition into the substrate of an equivalent amount of mineral salt, and it is even more efficient than the separate addition of the mineral salt on the one hand and the inactive yeast on the other hand (see example) . That is, the process according to the invention shows synergistic effects in terms of mineral nutrition. These synergistic effects can at least partially and ce in an increased mineral bioavailability favorable to the fermentation microorganism. The term "fermentation process" herein means that it includes the entire production process and is not limited to the precise biological stage of the fermentation. For example, it includes the stage of propagation of the fermentation yeast and the production process of the substrate. The term "nutrient" herein includes any element that may be considered to be of nutritional value to the fermenting microorganism, and therefore also comprises my trace or trace thereof. It is also pointed out that the word "yeast" means in the present a yeast cell which may be alive or inert, and which comprises at least one structure corresponding to a cellular structure i n s or lubl e. A preferred yeast for use according to the invention is a yeast enriched with minerals. At least one mineral-rich or mineral-enriched yeast is advantageously selected from the food-grade yeast genus. Examples of suitable yeasts include the genus Saccha romyces (for example S aecha romy ce s cerevisiae) and the genus Kl uyveromyces. In one embodiment of the present invention, at least one mineral-rich or mineral-enriched yeast is, prior to use, as obtained by the addition of approximately 1,000 to about 200,000 ppm (based on the weight of the yeast, as measured on a dry weight basis) of a salt of such mineral to a live yeast culture at a temperature of about 4-40 ° C, preferably about 25-32 ° C at a pH of between 3.5 to about 7.0, preferably from about 4.6 to 6.6 over a period of about 1-20 or 1-24 hours, preferably 2-16 hours to allow the yeast to incorporate, absorb and / or adsorb the minerals. Any salt, for example acetate, caprylate, carbonate, chloride, chromate, gluconate, iodate, lactate, oleate, oxide, perchlorate, peroxide, phosphate, salicylate, sulfate, sulfide, tartarate or valerate is appropriate. The comparative tests can be executed by persons skilled in the art to determine the most efficient source of mineral. Such mineral incorporation may correspond to absorption and / or adsorption. When incorporated, the mineral can remain as a mineral and / or transform into a salt and / or an organic form. It has been pointed out that the effectiveness of the use according to the invention is not necessarily directly and depends only on the concentration of the mineral resulting from the substrate: the b i odi sponibi 1 ity has also been taken into account. In another embodiment, at least one mineral-rich or mineral-enriched yeast is a commercially available product, for example a product of Danstar Ferment A.G. Mineral Enriched Yeast range. The yeast is advantageously rich in or enriched in at least one mineral that is capable of altering the metabolism of an alcoholic fermentation. An ability to alter the metabolism of an alcoholic fermentation can be easily determined by someone skilled in the art, for example by comparing the growth level of the fermentation microorganism, and / or the fermentation rate, and / or the metabolite concentrations secondary and / or the taste profile; in the presence and absence of the mineral candidate under standard appropriate laboratory conditions. The word "mineral" also includes in the present or the first one the title. Such a mineral is preferably a metal and more preferably a divalent metal. It is advantageously selected from the group consisting of zinc, magnesium, manganese. A more preferred mineral is generally zinc. But when dealing with the cancellation of the repressive effect of calcium and therefore the increase in sugar / alcohol conversion, then magnesium is preferred. At least one yeast rich in minerals or enriched with minerals can carry more than one nutrient mineral at a time, ie it can be a combination or a permutation of eg magnesium and zinc. The use of at least one mineral-rich or mineral-enriched yeast according to the invention is such that the mineral contained therein or therein is released for the benefit of the fermentor microorganism culture. Preferably, at least one mineral-rich or mineral-enriched yeast contains, before use, a concentration ranging from about 1,000 to about 200,000 ppm of each mineral it bears. One of the many advantages of the process and use according to the invention lies in the fact that at least one yeast rich in minerals or enriched with minerals can be supplied in any form appropriate to the precise fermentation process where it has to be used. It can be provided in a living form, or in an inactive form. It can be cellularly intact, although, as it is used as a source of nutrient and not for cellular production, it can be slightly separated at the cellular level. At least one yeast rich in minerals or enriched with minerals can in fact be used under a variety of forms including a dry form, a liquid form, a frozen form, a frozen dry form, a paste or a powder. It may have been sterilized or not. It can be used on its own or as a part of a mixture of other products. The process and use according to the invention can therefore be seen as the use of at least one yeast according to a nutrient source in alcoholic fermentations. Another advantage lies in the fact that the use can be executed, as desired at any stage of the fermentation process. A simple direct addition of at least one yeast rich in minerals or enriched with minerals in at least one stage of the fermentation process is efficient. It can therefore be added directly in the boiling vat and / or the fermenter and / or any vat between the two and / or within the vats containing or propagating the fermentation microorganism. For example, in the production of beer, the addition to the must may be performed during the alcohol production process or the propagation process of the fermentation microorganism, before or after boiling. At least one yeast rich in minerals or enriched with minerals can therefore be added directly to the wort so that it is killed during the boiling stage of the wort. It can also be added to the cooled must before, during or after the resettlement of the yeast. Preferably, at least one yeast rich in minerals or enriched with minerals is added to the boiling wort. Advantageously, the use according to the invention is executed so that the yeast is used as such in an amount and / or in such a concentration in the ore that it leads to an increase of at least about 0.05 ppm of the mineral content of the fermentation substrate. The substrate, fermented itself can be distilled or not. The use according to the invention is particularly efficient in that it accelerates the rate of alcoholic fermentation higher than when the mineral concentration was increased by the addition of equivalent concentration of the mineral when it was derived from a mineral salt. A synergistic effect can be further delineated when compared to the addition of the mineral salt on the one hand and the inert yeast on the other hand (see for example, laboratory tests 2 and 3 of example 1 for zinc). The duration of the necessary fermentation therefore decreases (see example below). The limit for primary fermentation is achieved faster, significantly compared to when the equivalent mineral concentration is derived from the mineral salt. The number of hours required to achieve the standard specific gravity (approximately 3.6 ° P or approximately 3.8 ° P for beer) is decreased: to the time necessary to achieve the degree of attenuation of the fermentation that is decreased by several hours (approximately 20 hours in the following examples with zinc). The use according to the invention also allows fermentation to advance to absolute dryness, ie to an absence of the residual fermentable sugars in the alcohol thus produced (see for example, example 2 below). Not only does it allow a high production of alcohol, but also a qualitatively better one (see for example, example 1 below). And finally, although not as a last point, despite the acceleration of the fermentation, the alcohol produced according to the invention has a flavor equal to or better than that which is produced when the equivalent mineral concentration is derived from the mineral salt (see for example, example 3 below). The process and use according to the present invention are of primary importance for the brewing industry, although it can also be applied to any alcoholic fermentation based on cereal, such as whiskey or sake yeast as well as fermentations based on fruit, sugar or honey. , such as wine, brandy, cider, fruity wines, mead, rum, tequila, industrial alcohols, potable alcohols, vodka, gin, e t c. The present invention also relates to the use of at least one mineral-rich or mineral-enriched yeast as a nutrient source as described herein for the production of alcohol by a fermentation process. The features and technical advantages of the present invention are further illustrated herein by several examples, which are given for purposes of illustration and are not intended in any way to restrict the scope of the invention. In those examples, reference is made to: - Figure 1 which represents the results of the brewery test 1 (Extracts [° Balling] as a function of the number of days of fermentation) and for - Figure 2 which represents in a manner similar to that of Figure 1, the results of the brewery test 2.

In figures 1 and 2, the legend is as follows: rhombuses: square wort-0: zinc yeast horizontal line: attenuation limit p r ima ry EXAMPLE 1: FERMENTATION SPEED Three laboratory tests and two brewing trials were carried out to show the relative effectiveness of sacrificing zinc yeast and the addition of zinc chloride to musts containing different natural zinc concentrations and then fermented by yeasts containing different natural concentrations of zinc.

Materials and Methods Materials Yeast strains and provenance (laboratory tests) In the results reported here, the sources of yeast were as follows: The yeast strain used in all laboratory tests was an S strain. c e re v ± s i a e (largest type) obtained from four commercial breweries in Germany. The sample taken was from their stock designated to be used for their next fermentation. The strain is for tests 1, 2 and 3 and in the brewery test 12 was deposited with the Technical University of Mun i ch - We i h e s t eph e n Hefebank, and was designated as serial number 34/70. The strain used in the brewing trial 1 is deposited with the Technical University of Mun i ch - e ih in st epha n Hefebank and designated as the strain number W 120. The yeast used for all laboratory tests was obtained , when it was necessary in the form of a cream from the proper brewery. The cream was centrifuged in a SORVAL® RC5B centrifuge machine at 2700g for 10 minutes and the supernatant was discarded. The yeast dough was weighed and resuspended in cooled, aerated wort and then added directly to the fresh musts. The zinc content of the yeast was measured before settling.

Half Ferment t ates of Pru eba de Labora t ori The must used was obtained from three commercial breweries in Germany. In trial number one, the must was used to make his "he lie" beer. In trial number two the must was used to make its "festbier" beer in trial number three the must was used to produce the "pilsner" type beer. In all cases the must was collected at the end of boiling and therefore was hopped to the normal level of that product for the particular beer. The musts had not been treated in the respective brewery in any way to alter the natural level of zinc. The musts were boiled for 15 minutes before being cooled to the fermentation temperature, 10 ° C, and settled with the fermentation yeast.

In fact, two of the brewery trials were carried out in two commercial breweries in Germany. The brewery in trial 1 was that of Brauerei Kreiger, 944505 Landau, D. Isar, Bavaria, Germany. During a normal production phase, two musts of type "he lie" numbers 22 and 23 produced on April 20 and 21, 1999 respectively were designated for experimental observation. They were produced from the same recipe, one immediately after the other, from the same stocks of malt and hops and brewery water. 110 hectoliters of must were harvested from each fermentation. The brewery in trial two was the P r i va tbr auer e Kitzmann, Kitzmann Braü KG, Südliche S t admaue r s t r s s 25, 91954 Erlangen Bavaria, Germany. During a phase of normal commercial production, a must, designated as fermentation number 120, produced on April 26, 1999, containing 286 liters of wort at 11.6 ° Balling, was separated into two termenors each containing one hundred and forty-three hectoliters of "pilsner" must. Both temperature profiles of the fermentations were as normal for the brewery for that type of beer.

Preparation of Zinc Pr u bers of the ab o ra t o ri o Mineral zinc, when used, was added in the form of zinc chloride in salt. This salt was used extensively by brewers throughout the world. Measurements of zinc in the wort and yeast samples were carried out using the atomic absorption method for the MEBAK® standard brewing analytical procedures, see for example Lutz, A.: Bestrmmung, Vorkommen und Verhalten von Kon t amina t ionen durch verschiede umwe 11 re le an te Spur ene 1 emen te in Bereich der Brauerei, Dissertation TU München, (1996). S21 ff.

Pro p a ra tio n of Sa c i f i c i a n a n c t i n e a Sacrificing yeast can be prepared by a person skilled in the art by any convenient method to produce a zinc-rich yeast. The standard methods use the incorporation, absorption and / or adsorption of zinc by yeast. It should be noted that to implement the present invention, the yeast may be live or inactive. The preparations used in the assays herein were produced in some way by the following method. Zinc, at a concentration of between 1,000 and 200,000 ppm (relative to the weight of the yeast or the yeast fraction, as measured on a dry weight basis), in the form of sulfate, chloride, acetate, zinc phosphate or some other suitable form of zinc was added to a live or inactive culture of S. ce re vi sa a temperature of approximately 4 to about 40 ° Celsius (preferably about 25-32 ° C) at a pH of between about 3.4 to about 7 (preferably about 4.6 to about 6.6), over a period of 1 to 20 or 24 hours to allow the culture to incorporate, absorb and / or adsorb the zinc. Two dry-base zinc yeast preparations were used in the tests: Preparation one contained 10,500 ppm of mineral zinc Preparation two contained 70,000 ppm of mineral zinc Other preparations of zinc yeast are also commercially available from Danstar Ferment AG, 20 Al p strasse, 6301 ZUG, Switzerland (MEY® Zn 50). All zinc preparations were added to the boiling musts at the start of boiling.

In summary, the state of the zinc in the yeasts and musts in the three laboratory tests and two beer brewing tests are as follows: Table 1 Preparation of Fermentation Yeast A portion of the test yeast, 30 grams of the paste, was resuspended in 250 milliliters of boiling wort and aerated for approximately five minutes by means of a magnetic stirrer. The preparation of the yeast was then divided into seven equal aliquots and settled on the appropriate test must. The one brewery test and the two brewery test were conducted in a similar way. The yeasts for the one brewery test and the two brewery test were collected from previous fermentations stored as a cream, under refrigeration conditions and settled for the normal procedure for the brewery. The yeast used for the fermentation was set at a level of 1.6 liters of yeast cream per hectolitre of wort (this is the normal yeast handling and settling procedures for this brewery) for the one brewery test and of 1.8 liters for the two brewery test. The zinc content of the yeast was measured before settling.

Experimental Methods Pr u bers of L a b o ra t o ri o The sample of the brewery must obtained was divided into 2.0 liters aliquots. For laboratory test 1, seven different types of aliquots were prepared and the additions were made for each as follows: Type 0 No addition Type 1 0.6 mg zinc chloride, which produced a measured increase of 0.28 ppm mineral zinc per liter present in the must.

Type 2 40 mg slaughter zinc yeast preparation (at 10,500 ppm zinc) which produced a measured increase of 0.24 ppm zinc present in the must. Type 3 160 mg of the slaughter zinc yeast preparation (at 10,500 ppm zinc) which produced a measured increase of 0.805 ppm zinc present in the must. Type 4 8 mg sacrifice zinc yeast preparation (at 70,000 ppm zinc) which produced a measured increase of 0.26 ppm zinc present in the must. Type 5 16 mg slaughter zinc yeast preparation (at 70,000 ppm zinc) which "" corresponds to 0.88 ppm additional zinc measured in the must. For laboratory test 2, six different types of aliquots were prepared and each was added as follows: Type 0 No addition Type 1 0.6 mg preparation of slaughter zinc yeast (at 70,000 ppm zinc) which corresponds to 0.16 ppm of additional zinc measured in the must.

Type 2 30 mg of the preparation of sacrificial zinc yeast (at 70,000 ppm zinc) which corresponds to 0.8 ppm measured of additional zinc in the must. Type 3 160 mg of the yeast of dry inactive brewers, which corresponds to no measured increase in the zinc content of the must. Type 4 0.6 mg zinc chloride, which corresponds to 0.15 ppm measured for additional zinc in the must. Type 5 addition of 80 mg of yeast from inactive dry brewers plus 0.6 mg of zinc chloride corresponding to 0.15 p m measures of additional zinc in the must. For laboratory test 3, six different types of aliquots were prepared and the additions were made for each as follows: Type 0 No addition Type 1- 4.6 mg preparation of slaughter zinc yeast (at 70,000 ppm zinc) which corresponds to 0.26 ppm measures of additional zinc in the must.

Type 2 160 mg of inactive dry brewer's yeast, which corresponds to 0.01 ppm measures of zinc increase in the must. Type 3 35 mg slaughter zinc yeast preparation (at 70,000 ppm zinc) that actually corresponds to a measured increase of 1.12 ppm zinc in the must. Type 4 2.5 mg zinc chloride, which really corresponds to a measured increase of 0.25 ppm zinc in the must. Type 5 Addition of 160 mg yeast from inactive dry brewers plus 0.6 g zinc chloride, which corresponds to a measured increase of 0.29 ppm zinc in the mo s t o. Each aliquot was boiled for 15 minutes. Zinc preparations were added at the start of boiling. The boiling vapors were condensed and returned to their respective batch in order to minimize the loss by evaporation. The must preparations were sealed, allowed to cool to 8 ° C, then settled with the appropriate amount of yeast.

In the Fab ri ca of Ce rve za For the brewery trial 1 as for the brewery trial 2, one fermenter received the equivalent of 0.30 ppm of additional zinc while the other did not receive nothing.

Fermentation Laboratory tests one, two and three The fermentation was carried out at a constant ambient temperature of approximately 10 ° C until a density of 3.6 ° P was reached. This is normal for beers that are transferred to lager beer under refrigeration conditions so that secondary fermentation and maturation can take place.

Beer Factory Tests The fermentation was carried out under the standard temperature program for that particular wort type. The standard and test musts were subjected to the same profile.

Measurements Laboratory tests one two and three The samples were extracted from the previous wort for settlement with the yeast and the zinc content was measured. Fermentation progress was measured through a standard brewer densitometer and recorded in plate grades after compensation for the effects of temperature. At the beginning of the fermentation zinc determinations were carried out in the treated and untreated musts and in the settling yeast. The determinations had previously been carried out outside the zinc yeast preparations. The beer finished in the three tests was analyzed using an "automatic beer analyzer" SCABA® from PERSTOP ANALYTICAL. SWITZERLAND, for the concentration of alcohol as expressed in volume by volume.

In the process of fermentation, samples were taken at regular intervals, and the progress of fermentation was measured by drip by wort density, as expressed in Balling grades.

Results and Conclusions Laboratory tests 1, 2 and 3 The time taken for each fermentation to reach 3.6 degrees Plate which is considered that when the primary concentration is complete and the alcohol concentrations after two hundred and four hours of fermentation, are detailed in the next table 2 for laboratory test 1, table 3 for laboratory test 2 and table 4 for laboratory test 3.

Table 4 Conclusions 1 In all the fermentation tests, sacrificial zinc yeast was added, the fermentation rate was improved compared to the standard must, the must with zinc chloride added and when it was tested, the must with inactive added yeast and the must with added zinc chloride plus inactive yeast.

In all the fermentation tests where sacrificial zinc yeast was added, the standard specific gravity, designated for progressive processing of the beer for aging, was achieved faster than the standard must, the added zinc chloride must and when it was tested , the must with inactive added yeast and the must with zinc chloride added plus the inactive yeast. The time to achieve this degree of attenuation of fermentation was at least twenty hours and a maximum of seventy-six hours less than the standard, against the test where zinc chloride was added, the sacrificial zinc yeast tests reached the standard fermentation attenuation in at least six and more in sixty-two hours before. Where the zinc addition was at a similar level from the mineral zinc (zinc chloride), and the biological zinc (sacrificial zinc yeast), the sacrificial zinc yeast experiments were in a measured and significant way faster.

In all the fermentation tests, where the 'sacrificial zinc' was added, the final concentration of the alcohol produced after ten days was higher than the standard must, the must containing zinc chloride and when it was tested, the must containing the inactivated yeast and the must containing the zinc chloride plus the inactivated yeast.

Ens ayo 1 y enso 2 de alebri ca of beer The data collected from the fermentation test of beer test 1 and 2 are shown in table 5 below. The graphic representation of these data are shown in Figure 1, for the brewery 1 test and in Figure 2 for the brewery 2 test. Table 5 Conclusions Fermentation containing slaughter zinc yeast was faster than standard untreated wort. in the fermentation tests when the slaughter zinc yeast was added, the standard specific gravity, 3.8 and 3.6 degrees Balling respectively designated for the progressive processing of the beer for aging was achieved in one hundred and forty hours before (trial 1), and forty and eight hours before (trial 2) than the standard untreated must. The two beers produced were tested on the part of professional brewers and others with professional beer tasting experience. The test beer was considered to be at least as good as the standard and was preferred by many. The tasters noted that both test beers were particularly minor in the "sulfurous" character. This is of particular importance and meaning not only indicates a beer (cleaner) but indicates a possibility of progress in the maturation process and therefore a reduction in aging times and costs. At a cellular level, the addition of zinc according to the invention can show the following stimulatory effects: stabilizing proteins and membrane systems, which act as a catalytic center of essential enzymes (for example, of hydrogens to alcohol, aldolase and hydrogenation of acetyl aldehyde), improving the synthesis of riboflavin, activating the alkaline synthesis and "acid, stimulating the uptake of maltose and maltotriose.

EXAMPLE 2: Analysis of residual sugar After two hundred and four hours of fermentation of the laboratory test, the residual sugars in all the beers of test 1 were analyzed by gas liquid chromatography. The results are detailed below in table 6.

Conclusions It is clear from the data presented above that the inclusion of the sacrificial zinc yeast allows the fermentation to advance to absolute dryness. That is, there are no fermentable sugars left in the beer. This is highly important as it will allow brewers to produce beers free of residual fermentable sugars much faster than they are today. The technical characteristics of the process according to the invention thus lead to higher alcohol produced, thereby giving an economic advantage.

EXAMPLE 3: The quality and quantity of the secondary taste compounds After the completion of the fermentations in the laboratory test 2 (see example 1 above) the beer was subjected to the G.L.C. to see if the accelerated fermentations affected the quality and quantity of the secondary flavor components. The results are detailed below in table 7. Table 7 Conclusions It is evident from the previous results that the acceleration of fermentation by sacrificial zinc yeast does not have a significant negative effect on the principal, secondary, organoleptically active metabolites. In fact, this negative effect has not been observed in any of the tests and trials carried out (see example 1 above). This is a particularly striking effect of the process of the invention that allows an accelerated fermentation without adversely affecting the alcohol profile of the product. These conclusions about the quality of the beer produced according to the invention were further confirmed by blind tasting panels. This is an important finding since it allows a standard beer to be produced at a higher speed and therefore in a more efficient way.

It will be apparent to those skilled in the art that the process of the present invention comprising the use of a mineral-rich yeast, and in particular of a zinc-rich yeast, as a fermentation nutrient is a very valuable technical contribution to " Additive-free beer brewing It will also be apparent that the foregoing examples have been for the purpose of illustration and that a number of changes and modifications can be made without departing from the scope of the invention. Zinc can therefore be implemented without undue problems with a yeast rich in any mineral or combination of minerals suitable for a process of improving the growth of the yeast, for example, magnesium, or manganese.

Claims (19)

1. Process for alcoholic fermentation comprising the use of a fermentation microorganism, characterized in that it also comprises the use of at least one yeast rich in minerals or enriched with minerals as a source of nutrient for such fermentation.

2. Process according to the claim 1, characterized in that at least one yeast rich in minerals or enriched with minerals belongs to the genus S a e ch a romy c s o the genus Kl uy ve romy e e s.

3. Process according to one of claims 1 or 2, characterized in that at least one yeast rich in minerals or enriched with minerals is prior to the use obtainable by the addition of 1,000 to 200,000 ppm (relative to the weight of the yeast, as was measured on a dry weight basis) from a salt of the mineral to a live culture of microorganism at a temperature of 4-40 ° C at a pH of between 3.5 to 7.0 over a period of 1-24 hours, to allow the microorganism is incorporated into the mineral.

4. Process according to claim 3, characterized in that the temperature is in the range of 25 to 32 ° C.

5. Process according to claim 3, characterized in that the pH is in the range of 4.6-6.6.

6. Process according to claim 3, characterized in that the period of time is in the range of 2-16 hours.

7. Process according to any of the above indications 3-6, characterized in that the salt is selected from the group consisting of acetate, caprylate, carbonate, chloride, chromate, gluconate, iodate, lactate, oleate, oxide, perchlorate, peroxide, phosphate, salicylate, sulfate, sulfur, tartarate or valerate.

8. Process according to any of claims 3-7, characterized in that the incorporation of the mineral corresponds to an absorption and / or an adsorption.

9. Process according to any of the rei indications 1 to 8, characterized in that the mineral is a metal capable of altering the metabolism of fermentation.

10. Process according to any of claims 1 to 9, characterized in that the mineral is selected from the group consisting of zinc, magnesium and manganese.

11. Process according to any of the preceding claims, characterized in that at least the mineral-rich or mineral-enriched yeast contains before being used a concentration in the mineral ranging from 1,000 to 200,000 ppm.

12. Process according to any of the preceding claims, characterized in that at least one yeast rich in minerals or enriched with minerals is used in a form selected from the group consisting of a living form and an inactive form.

13. Process according to any of the preceding claims, characterized in that at least one yeast rich in minerals or enriched with minerals is used under a form selected from the group consisting of a dry form, a liquid form, a frozen form, a form cong e 1 a da - se, a paste, a powder.

14. Process according to any of the preceding claims, characterized in that at least one yeast rich in minerals or enriched with minerals is used by the direct addition of at least one stage of the fermentation process.

15. Process according to the rei indication 14, characterized in that the addition is executed directly in 'at least one element selected from the group consisting of a fermentor, a boiling vat and any vat between the two, a containment vat of fermentation microorganism or a containment vat of fermentation microorganism.

16. Process according to any of the preceding claims, characterized in that the yeast is used in such amount and / or in a concentration in the ore that leads to an increase of at least 0.05 ppm of the mineral content of the fermentation substrate .

17. Process according to any of the preceding claims, characterized in that the alcoholic fermentation can lead to the production of beer.

18. Process according to any of the preceding claims, characterized in that the alcoholic fermentation can be conducted until the production of an alcohol selected from the group consisting of whiskey or sake, as well as fermentations based on fruit, sugar or honey, such as wine, brandy, cider, fruit wines, mead, rum, tequila, industrial alcohols and potable alcohols.

19. Use of fermentation microorganisms and at least one yeast rich in minerals or enriched with minerals as a source of nutrient in the production of an alcohol by fermentation.