194 VINEGAR, CIDER, AND FRUIT- WINES. 



If the fresh lees are thrown in a pile and allowed to ferment, 

 considerable heat will be developed in the course of a few days, 

 in fact so much that the mass commences to steam. When fer- 

 mentation is finished, or shortly before, an agreeable odor of acetic 

 ether is evolved, which is due to the commencement of the devel- 

 opment of vinegar ferment upon the lees and the formation of 

 acetic acid, the latter combining with a certain quantity of the 

 alcohol formed by fermentation to acetic ether. (At this stage in 

 the change of the lees a small quantity of acetic ether can be ob- 

 tained from them by distillation.) 



The odor of acetic ether is soon overcome by that of acetic 

 acid, the conversion of the newly-formed alcohol into acetic acid 

 now progressing rapidly on the surface of the lees. Later on the 

 sharp odor of acetic acid again decreases, the greater portion of it 

 being destroyed by mold and other ferments, the development 

 of which now progresses with great rapidity in the thoroughly 

 heated mass of lees ; lactic acid is formed, and later on the mass 

 acquires a rancid odor calling to mind that of old cheese, which 

 is due to butyric acid, valeriauic acid, etc. The lees gradually 

 acquire a darker color and finally putrefaction sets in. 



If only the sugar still contained in the lees is to be obtained 

 and vinegar to be prepared in the most simple manner, the fol- 

 lowing process may lye used : The mass of lees as it comes from 

 the press is broken up and put in a pile, where it is left to itself 

 until it becomes warm and acquires the odor of alcohol and acetic 

 ether. The mass is then shovelled into a vat and gently pressed 

 together with a shovel. For every 220 Ibs. of lees us<$, about 10 

 quarts of water are now sprinkled over the mass by means of a 

 watering-pot. By the entrance of air while shovelling the pile of 

 lees into the vat the action of the vinegar ferment has been accele- 

 rated and a considerable quantity of alcohol converted into acetic 

 acid, which is indicated by the stronger vinegar odor. The 

 water permeating the lees almost completely displaces the fluid 

 containing the alcohol and acetic acid, the latter running oft 

 through an aperture in the bottom of the vat. It is collected 

 in a shallow vessel placed in an apartment having the ordinary 

 temperature of a living room, and is allowed to rest. The vine- 

 gar ferment present in abundance in the fluid rises to the surface, 



