Method of producing an alcoholic beverage having a fruity flavor

Abstract

The invention concerns a method of producing an alcoholic beverage by fermentation having flavor and taste of passion fruit and grapefruit, characterized in that it comprises the following steps: providing a gas stream containing hydrogen sulfide, bubbling the gas stream containing hydrogen sulfide into a grape juice and/or grape juice derived fractions prior to yeast inoculation, and/or during fermentation. The alcoholic beverage obtainable by the method can be chosen from the group constituted by wines, beers and spirits. Most preferably, the alcoholic beverage is a Sauvignon Blanc wine.

Claims

1. A method of producing an alcoholic beverage by fermentation comprising: providing grape juice in a tank; introducing a gas stream comprising about 6 ppm to about 13 ppm hydrogen sulfide into the grape juice to cause bubbling of the grape juice; inoculating the bubbling grape juice with yeast to initiate fermentation; and continuing the fermentation to obtain the alcoholic beverage.

2. The method of producing an alcoholic beverage according to claim 1, wherein the produced alcoholic beverage has higher levels of 3MH and 3MHA in comparison to an alcoholic beverage obtained without the bubbling of the grape juice with the gas stream.

3. The method of producing an alcoholic beverage according to claim 1, wherein the gas stream containing hydrogen sulfide which is bubbled into the grape juice is stopped midway through the fermentation.

4. The method of producing an alcoholic beverage according to claim 1, wherein the gas stream containing hydrogen sulfide is taken from an existing wine fermentation culture producing hydrogen sulfide naturally.

5. The method of producing an alcoholic beverage according to claim 1, wherein the introducing of the gas stream is carried out with sintered gas spargers.

6. The method of producing an alcoholic beverage according to claim 1, wherein the alcoholic beverage is selected from the group consisting of wines and spirits.

7. The method of producing an alcoholic beverage according to claim 1, wherein the alcoholic beverage is a Sauvignon Blanc wine.

8. The method of producing an alcoholic beverage according to claim 1, wherein the grape juice is obtained from grapes of the Sauvignon Blanc variety.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1 is a graph showing the influence of the bubbling of hydrogen sulfide into grape juice on the synthesis of the volatile thiols 3MH and 3MHA during the production of Sauvignon Blanc wine.

(2) FIG. 2 is a diagram showing the influence of the bubbling of hydrogen sulfide into grape juice on the generation of the volatile thiols 3MH and 3MHA during the production of Sauvignon Blanc wine.

(3) In an early experiment the gas stream containing hydrogen sulfide came from a 300 000 L tank fermenting 10% of the sugar content per day. At the stage of ferment when the hydrogen sulfide was captured it was producing about 1.5 million liters of carbon dioxide per day. The gas stream contained 10 mg/L of hydrogen sulfide so was therefore supplying 15 kg of hydrogen sulfide per day to the receiving ferment.

(4) This gas stream was bubbled under the surface of a tank holding 130 000 L of grape juice.

(5) The levels of the thiols 3MH and 3MHA were measured as a function of time starting from the inoculation of the grape juice with yeast. In FIG. 1, the x-axis represents the days from inoculation and the y-axis denotes the combined molar concentration of 3MH and 3MHA (nMol/L) as well as the sugar concentration measured in degrees Brix.

(6) The curve entitled “Control 3MH+3MHA” represents the evolution of the combined concentration of 3MH and 3MHA in function of time starting from yeast inoculation, when the Sauvignon Blanc wine is produced in the absence of a bubbling of hydrogen sulfide.

(7) The curve entitled “Gas 3MH+3MHA” represents the evolution of the combined concentration of 3MH and 3MHA in function of the time starting from yeast inoculation, when the Sauvignon Blanc wine is subjected to a bubbling of hydrogen sulfide, i.e. according to the method of the present invention. The gas was taken from a 300 000 L wine ferment that was fermenting fast and produced about 10 mg hydrogen sulfide per liter of carbon dioxide. The gas supplemented ferment had a volume of about 130 000 L.

(8) The curve entitled “Control Brix” shows the progress of the fermentation, i.e. the reduction of the sugar content over time, when the production of wine is carried out in the absence of a bubbling of hydrogen sulfide.

(9) The curve entitled “Gas Brix” shows the progress of the fermentation, i.e. the reduction of the sugar content over time, when the production of wine is carried out in the presence of a bubbling of hydrogen sulfide, i.e. according to the method of the present invention.

(10) The graph of FIG. 1 shows that no thiols are present in the non-inoculated grape juice. Thiols are generated in the early phase of the fermentation and in this case leveled off, with a further smaller increase towards the end of fermentation.

(11) In the experiment according to the invention, the gas containing hydrogen sulfide was turned off after two days into ferment, because the feed ferment stopped producing hydrogen sulfide.

(12) In view of the graph of FIG. 1 it can be noticed that the production of thiols 3MH and 3MHA is higher when the production of wine is subjected to a bubbling of hydrogen sulfide, i.e. according to the present invention, than in the absence of hydrogen sulfide bubbling.

(13) More precisely, 15 days after inoculation, the level of thiols 3MH and 3MHA of: the Sauvignon Blanc wine produced with bubbling of hydrogen sulfide (i.e. by the method according to the present invention) is 27 nMol/L; the Sauvignon Blanc wine produced without bubbling of hydrogen sulfide is 18 nMol/L (i.e. after following standard methods).

(14) Thus, the combined level of thiols 3MH and 3MHA in the Sauvignon Blanc wine produced according to the method of the present invention is 1.5-fold higher than in a Sauvignon Blanc wine produced according to standard methods (i.e. without a bubbling of hydrogen sulfide).

(15) In another experiment, the off-gas from a naturally hydrogen sulfide producing ferment was captured and bubbled through a non-inoculated Sauvignon Blanc grape juice kept between 4° C. and 10° C.

(16) After 4 days the treated (bubbling) and non-treated (no bubbling) juices were inoculated with the commercial yeast strain Zymaflore X5 (Laffort) and fermented according to industry standards (i.e. 20 g of yeast per 100 L of juice).

(17) Thiols (3MH and 3MHA) were later measured in the finished wines.

(18) The diagram of the FIG. 2 shows: the level of 3MH and 3MHA in a 20 000 L tank in which no hydrogen sulfide was bubbled into (i.e. “control”); the level of 3MH and 3MHA in a 20 000 L tank in which hydrogen sulfide was bubbled into (i.e. “+H.sub.2S ferm-gas”);

(19) FIG. 2 shows that 3MH increased by 48% and 3MHA increased by 88% in the hydrogen sulfide treated juice compared to the control tank.