The chemical testing of wines and spirits / by John Joseph Griffin.
- John Joseph Griffin
- Date:
- 1866
Licence: Public Domain Mark
Credit: The chemical testing of wines and spirits / by John Joseph Griffin. Source: Wellcome Collection.
133/160 page 121
Licence: Public Domain Mark
Credit: The chemical testing of wines and spirits / by John Joseph Griffin. Source: Wellcome Collection.
![ACIDS AFFECTED BY FERMENTATION. Alcohol.—Multiply the Alcohol by 1*25. The product is the weight of the Acetic Acid. b. To find the Weight of the Alcohol which produces a given Weight of Acetic Acid.—Multiply the Acetic Acid by *8. The product is the weight of the Alcohol. No wine exists free from acetic acid. Its production seems to com- mence at the very beginning of every fermentation. It is apparently an unavoidable constituent of wines ; and possibly one that is useful and necessary. With alcohol, it forms the volatile and odorous acetic ether, which seems to form part of the aroma of every wine. The average free volatile acid of the 19 wines enumerated at page 73, is 100 grains in a gallon. Reckoning this to be acetic acid, it would, according to the above formula, take 80 grains of alcohol per gallon to yield it. Consequently, in providing sugar to produce in wine a given weight of alcohol per gallon, this average source oi loss of alcohol—80 grains per gallon—should be provided for. Loss and Gain of Acid by Must during Fermentation. 202. According to Berthelot, there is a great diminution in the acid of Must during the first few days of the vinous fermentation ; the acid destroyed being chiefly malic acid, not tartaric. He gives the fol- lowing examples [which I have expressed according to the system used in this book as grains in a centigallon]. The acidity is valued as if tartaric acid :— 1. Original acidity 7’00 grains. Acidity after 15 clays’fermentation . 4-06 Loss . . 2*96 2. Original acidity Acidity after 6 days’ fermentation 7 * 07 grains. 5'67 Loss 1 ‘4 3. Original acidity Acidity after 7 days’ fermentation . Acidity after 4 months’ fermentation 6’09 grains. 2 ‘94 4’4I Loss . . 1 • 68 I do not find statements of such losses of acid in any other work. But indeed the matter, though important, is one to which wine-makers seem to have hitherto paid no attention.](https://iiif.wellcomecollection.org/image/b28126981_0133.jp2/full/800%2C/0/default.jpg)
