Fig. 7.
Growing Yeast After 8 Hours’ Propagation.
Being devoid of the green coloring matter of the plant (chlorophyll), the yeast cell is incapable of assimilating inorganic matter, such as carbon, nitrogen, ammonia and certain mineral salts, for the purpose of building up their tissues.
Yeast belongs to the family of Fungi, and on account of the peculiar manner of its reproduction is classified as “Sprouting Fungi.”
We are obliged to admit that the true nature of the yeast cell has as yet never been entirely satisfactorily explained. Some scientists are of the opinion that yeast cells are but the embryo of higher fungi development; for it is known as a fact that certain species of the sprouting fungi do not possess the faculty to incite alcoholic fermentation, while, on the other hand, some of the higher species of mould fungi possess the qualification not alone to incite alcoholic fermentation, but are also capable of ascospore formation. So much for this explanation.
It has been proven by actual results that different species of yeast produce widely different kinds of fermented liquid. These differences are recognized in the yeast cell of wine, of beer, and of the distillery, the last named being also the yeast of dough fermentation.
If the yeast cell of wine be placed in a beer wort, the fermented wort will assume a vinous flavor, and is known as maltine.
Science has shown that yeast cells are composed of groups of various species. The principal species, among others, as found in brewers’ or distillers’ yeasts, are known as Sacchoromyces Cerevisial and Sacchoromyces Pastorianus.