Production of alcoholic beverages

A process for producing alcoholic beverages, comprising subjecting a starting brew liquor to a first fermentation under aerobic conditions, in a first fermentation zone, during which substantial proliferation of a yeast takes place, for a period of time so that consumption of .alpha.-amino nitrogen reaches a predetermined level;

• and subsequently to a second fermentation, in a second fermentation zone, during which no substantial proliferation of a yeast takes place, for a period of time such that consumption of carbon reaches a predetermined level, said second fermentation being practiced with a yeast present at a concentration of at least 0.4% based on dry cell weight per volume of starting brew liquor (w/v in g/ml), said yeast being immobilized within a hydrogel, the fermented liquor obtained from the first fermentation being heated prior to the second fermentation to a temperature of about 60.degree. to about 100.degree. C. for a period of time of up to about 40 minutes, whereby vicinal diketone precursors are converted into readily decomposable vicinal diketones.

A process for producing alcoholic beverages, comprising subjecting a starting brew liquor to a first fermentation, in a first fermentation zone, for a period of time so that consumption of carbon after a second fermentation reaches a predetermined level, during which first fermentation no substantial proliferation of a yeast takes place, and subsequently to the second fermentation, in a second fermentation zone, during which substantial proliferation of a yeast takes place, said first fermentation being practiced in the presence of an immobilized yeast at a concentration not less than 0.4% and also at a temperature of 4.degree. C. or less, under anaerobic conditions or both, and said second fermentation being practiced in the presence of a yeast at a concentration less than 0.4% under aerobic conditions for a period of time such that diacetyl concentration in a fermented liquor product of said fermentations does not exceed 1 ppm and consumption of .alpha.-amino nitrogen reaches a predetermined level, said concentrations of yeast being based on dry yeast cell weight per volume of starting brew liquor (w/v in g/ml).

A process according to claim 12, wherein the starting brew liquor is malt wort or fruit juice.

A process for producing alcoholic beverages, comprising subjecting a starting brew liquor to a yeast at first fermentation in a first fermentation zone, subsequently to a second fermentation under aerobic conditions, in a second fermentation zone, during which substantial proliferation of a yeast takes place, said first fermentation being practiced in the presence of an immobilized yeast a concentration not less than 0.4% and for a period of time such that consumption of carbon after the second fermentation may reach a predetermined level, and the fermented liquor obtained from the first fermentation being heated prior to the second fermentation to a temperature of about 60.degree. to about 100.degree. C. for a period of time of up to about 40 minutes, whereby vicinal diketone precursors are converted into readily decomposable vicinal diketones, and said second fermentation being practiced in the presence of a yeast at a concentration less than 0.4% under aerobic conditions for a period of time such that diacetyl concentration in a fermented liquor product of said fermentations does not exceed 1 ppm and consumption of .alpha. amino nitrogen reaches a predetermined level, said concentrations of yeast being based on dry yeast cell weight per volume of starting brew liquor.