Alcohol, Its Various Forms and Sources. The Preparation of Mashes and Fermentation.

Alcohol, Its Various Forms and Sources. The Preparation of Mashes and Fermentation.

Alcohol may be produced either from (1) farinaceous materials, such as potatoes or grains, or (2) sacchariferous substances, such as grapes, sugar beets, sugar cane, or the molasses produced in sugar manufacture.

THE PREPARATION OF STARCHY MATERIALS.

Saccharification. Preparatory Mashing. With starchy materials it is first necessary to convert the starch into a sugar from which alcohol can be produced by the process of fermentation. This is called saccharification.

Gelatinizing. The first step in this process is gelatinizing the starch—that is, forming it into a paste by heating it with water or into a liquid mass by steaming it under high pressure. The liquid or semi-liquid mass is then run into a preparatory mash vat and cooled.

Saccharifying. The disintegrated raw materials or gelatinized starch in the preparatory mash vat is now to be “saccharified,” or converted into sugar. [9] This is effected by allowing malt to act on the starch. This malt contains a certain chemical “ferment,” or enzyme, called “diastase” (“I separate”).

This is able under proper conditions to break up the gelatinized starch into simpler substances—the dextrins—and later into a fermentable sugar called maltose.

Fermentation—The maltose or sugar in the “mash” is now to be converted into alcohol. This is accomplished by fermentation, a process of decomposition that converts the sugar into carbonic acid and alcohol. Fermentation is started by yeast, a fungus growth, which in the course of its life history produces a matter called zymase, which chemically acts on the sugar to split it up into carbonic acid gas and alcohol.

Yeast may be either “wild” or cultivated. If the mash is left to stand under proper conditions, the wild yeast spores in the air will soon settle in the mash and begin to multiply. This method of fermentation is bad because other organisms than yeast will also be developed—organisms antagonistic to proper fermentation. As a consequence, pure or cultivated yeast alone is used.

This yeast is cultivated from a mother bed in a special yeast mash and, when ripened, is mixed with the mash in the fermenting vat. At a temperature between 50° F and 86° F. The yeast induces fermentation, converting the sugar of the [10] mash into carbon dioxide, which escapes, and alcohol, which remains in the decomposed mash, or “beer,” as it is termed in the United States.

It now remains to separate the alcohol from the water of the beer with which it is mixed. This is accomplished by distillation and rectification, as will be fully described in the chapters following.

PRODUCTION OF ALCOHOL FROM SACCHARIFEROUS SUBSTANCES.

Substances such as grape juice, fruit juice, sugar beets, cane sugar, and molasses already contain fermentable sugar. Saccharification is therefore not needed, and juices or liquids from these matters are either directly fermented, as in the case of sugarcane, or—as in the case of sugar beets—the sugar in juice is transferred by yeast into a fermentable sugar.