High-gravity brewing: effects of nutrition on yeast composition, fermentative ability, and alcohol production.

摘要: A number of economic and product quality advantages exist in brewing when high-gravity worts 16 to 18% dissolved solids are fermented. Above this level, production problems such as slow or stuck fermentations poor yeast viability occur. Ethanol toxicity has been cited the main cause, brewers' yeasts reported tolerate only 7 9% (vol/vol) ethanol. The inhibitory effect high osmotic pressure also implicated. In report, it is demonstrated that factor limiting levels ethanol by actually a nutritional deficiency. When nitrogen source, ergosterol, oleic acid added up 31% solids, possible produce beers 16.2% Yeast remains high, can be repitched at least five times. Supplementation does not increase fermentative tolerance but increases length level new cell mass synthesis over seen unsupplemented wort (and therefore period more rapid attenuation). Glycogen, protein, sterol were examined, was importance pitching rate, temperature, degree anaerobiosis. suggested no different than sake distillers' yeast.