On fermentation / by P. Schützenberger.

  • Schützenberger, P. (Paul), 1829-1897.
Date:
1883
Catalogue details

Licence: Public Domain Mark

Credit: On fermentation / by P. Schützenberger. Source: Wellcome Collection.

    151/388 (page 139)
    Thus, -424 gramme of pure sugar-candy, made to ferment with a weight of damp yeast corresponding wkh 10 grammes of dry matter, furnished, at the end of two days, 300 cubic centimètres of carbon dioxide ; the sugar alone could only furnish iio cubic centi- mètres. The liquid, carefully distilled, gave a little more than 0‘6 gramme of absolute alcohol. The weight of alcohol obtained was greater than the whole weight of the sugar employed, and in proportion to the volume of carbon dioxide formed. Tins experiment proves that when yeast is mixed with a comparatively very small weight of sugar, after the latter has been decomposed, the activity of the yeast continues, reacting on its own tissues and its hydrocarbons with extraordinary energy and rapidity, proceeding more and more slowly as the process goes on. If we put an end to the fermentation at the moment when a volume of carbon dioxide is formed, equal or very httle greater than that which corresponds with the ueight of the sugar employed, we jînd no more sugar in the liqiior. This observation is very important, because it tends to prove that the action which the yeast exerts on its own éléments does not commence till it is de- prived of sugar. It is not necessary to fulfil the conditions of the preceding experiments (fermentation with excess of yeast), in order to observe fermentation at the expense of the éléments of the yeast itself ; it is sufficient, as Pasteur has already shown, to mix fresh beer-yeast with water at 25° C. (77“ F.) ; we soon see numerous bubbles