Page:A Practical Treatise on Brewing (4th ed.).djvu/131

Rh drink. The harsh disagreeable bitter, however, which hangs, for a length of time, on the palate, is at once perceptible to any good judge, and warns him against its continued use.

As the fermentation of malt worts for making vinegar is generally carried on at a much higher temperature, than that commonly used for beer, it has been thought that this high temperature is absolutely necessary for their after acidification; and it probably in some way facilitates that change. This mode of working being peculiar to the manufacture of vinegar, has procured for the process the name of the Acetous Fermentation; but we know, that no more acidity is generated in the gyle-tun during the fermentation for vinegar than in that for beer, unless it proceeds from other causes. It is so far, therefore, only the vinous fermentation of a malt wort, to be converted into vinegar by an after process.

It is even doubtful, however, whether the after process can be properly called a fermentation; for at the time the greatest acidification may be going on, there is often very little appearance of effervescence or fermentation. The fermented wort is converted into vinegar by its being exposed in open vessels, to imbibe oxygen from the atmosphere, and the acidification appears to be accelerated by heat,