Premium
THE GROWTH AND FERMENTATION OF SOME TOP‐FERMENTATION BREWERY YEASTS WITH AMINO ACIDS AS NUTRIENTS
Author(s) -
Thorne R. S. W.
Publication year - 1942
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1942.tb06167.x
Subject(s) - fermentation , nutrient , food science , yeast , chemistry , amino acid , free amino nitrogen , biology , biochemistry , organic chemistry
Not much attention has been paid to the biological analysis and comparative study of the behaviour of British top‐fermentation yeasts owing, perhaps, to the fact that pure yeast cultures are not used in the breweries of this country. It was with the object of obtaining some knowledge of the different kinds of yeast used here and of the differences—if any—in their nutritional needs and behaviour that the experiments described in this paper were undertaken. Samples of yeasts were gathered from breweries in various parts of the country and pure cultures prepared from them of which 6 were chosen for further examination. These were grown in a synthetic nutrient medium containing ammonium phosphate or an amino acid as the source of nitrogen and measurements were made of their growth and fermentation in these various nutrients. It appeared that at least 5 of these 6 yeasts represented noticeably distinct types differing from each other in respect of their rate and extent of growth, in the rate at which they ferment under laboratory and under brewery conditions, and in the extent to which they flocculate. There is no doubt that the examination of a wider range of native brewery yeasts would disclose still further varieties and gradations between different varieties. It was also observed, as was to be expected, that the nitrogen sources differed from each other in the facility with which they promoted yeast growth and fermentation. But an underlying regularity was found to apply to the behaviour of these yeasts when grown on different nitrogen sources which may be illustrated by saying that if a yeast A grows, say, 50 per cent. better than another yeast B in some particular nitrogen nutrient, it will still grow 50 per cent. better than B when they are grown in any other nutrient even though the actual amounts of growth in the two nutrients may be quite different.