Stale yeast produces, instead of vinous fermentation, an acetous fermentation, which flavours the bread and makes it disagreeable.

This author belongs to a class of well-meaning gentlemen, so unfortunately constituted that the distractions of their time induce in them an acetous fermentation (as milk sometimes sours during thunder); and from acid becoming acrid, they at length fall fairly in love with the Erinnyes, and henceforth dote upon destruction and ugliness as happier lovers do upon cosmical health and beauty.

Sourness N. sourness &c adj.; acid, acidity, low pH; acetous fermentation, lactic fermentation. vinegar, verjuice^, crab, alum; acetic acid, lactic acid.

Adj. sour; acid, acidulous, acidulated; tart, crabbed; acetous, acetose^; acerb, acetic; sour as vinegar, sourish, acescent^, subacid [Chem]; styptic, hard, rough.

The Reformation had passed the period of its vinous fermentation, and its clarified results remained as an element of intellectual impulse and exhilaration; there were signs yet of the acetous and putrefactive stages which were to follow in the victory and decline of Puritanism.

The different stages of fermentation are noted scientifically as alcoholic, acetous, and putrefactive.

If this fermentation continues long enough, the acetous fermentation is set up, and acetic acid, the essential element of vinegar, is formed and the dough becomes sour.

If the fermentation is allowed to proceed until the acetous fermentation has begun, the loaf, when baked, will be "sad" and heavy, since there is no longer any gas to puff it up.

It is not enough, however, to prevent bread from reaching the acetous or sour stage of fermentation.

Fermentation may be carried so far as to destroy much of the richness and sweetness of the loaf, and yet be arrested by the baking process just before the acetous stage begins, so that it will be light and porous, but decidedly lacking in flavor and substance.

It is better to begin the baking before it has perfectly risen them to wait until it has become so light as to commence to fall, since if the fermentation proceeds too far, the sweetness of the grain will be destroyed, and the bread will be tasteless and innutritious, even if it does not reach the acetous stage.

This, from being mixed with the saccharine matter of the grain, soon runs into the acetous fermentation, and the weak acid thus formed by digesting on the fecula renders it white.