1868 The complete Practical Distiller

THE COMPLETE PRACTICAI DISTILLER.

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however, is by no means so complete as of the sugar, many of the full-bodied ales, for example, retaining much of their clamminess and gelatinous density, even after having undergone a very perfect fermentation. Atmospheric air, it seems, has a no less share whatever in vinous fermentation ; for it will take place full as welj in closed as in open vessels, provided space is allowed for the expansion of the materials and the copious production of gas. The great question to be determined is, What may be the substance or circumstance which disposes sugar to ferment ? for it has been proved that sugar will not of itself begin this spontaneous change into carbonic acid and alcohol, though when once begun the process will probably go on without further assistance. Some of the most common fermenting ingredients, as the sweet in- fusion of malt, technically called wort, it is well known, will slowly enter into fermentation without the addition of yeast; hence chemists have sought in this substance for the principle which gives the first impulse to the fer- mentation of sugar. Generally, it has been supposed that no substance en- ters into the vinous fermentation except sugar, or from which sugar may be extracted, and that the process of malting grain was necessary to develop the sugar or sac- charine matter, to render it susceptible of vinous fermenta- The practice, however, of grain distillers proves this to be a mistake, as they obtain as much spirit from a mix- ture of malted barley with unmalted grain as if the whole were malted. The properties of the fermented liquor, its odour, pungency, and intoxicating quality, are owing to the presence of a substance which can be separated horn tion.