1857 The Bordeaux wine and liquor dealers' guide

80

A TREATISE ON

those grapes that produce the most perfect wines, the relative proportions of the exciters of fermenta– tion and the sugar are so accurately proportioned by nature, that the whole of the former are decom– posed, and nearly the whole of the latter converted into alcohol; so that the liquid (wine) is left in a state not liable to future change. The chiefproduct of the vinous fermentation is alcohol, but there are other substances simultaneously produced and which remain associated with fermented liquor. Among the principal of these are renanthic acid and renan– thic ether; neither of which exists previous to fer– mentation, and are generally supposed to result from the action of the nitrogenizcd matters of the solution on the sugar. It has been determined by the researches of HK. Colin and ThenMd, and more recently by those of Fremy and ROU8seau, that the peculiar condition of the nitrogenized matter constituting the ferment materially influences the nature of the fermentation. The essential condition of a ferment, to be able to ex– cite the vinous fermentation,· is to be sufficiently acidulous to a~t on colored paper ; and this acidity should arise from the presence of certain vegetable acids and salts, capable of conversion into carbonic acid and carbonates, by their spontaneous decompo– sition. Those acids and salts which are found to

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