154 Joiir)ial of Agriculture. [lo March, 1910. 



acid bacillus, the development of which is interfered with at the expense 

 of the quality of the resulting product. 



In the presence of sugar, the acetic ferment itself often behaves in a 

 faulty manner, producing, instead of the thin film or veil on the surface 

 characteristic of healthy fermentation, a gelatinous membrane at the bottom 

 of the cask. This mass, often termed mother of vinegar, is an indication 

 of faulty conditions, and its formation is to be avoided. 



In order to insure complete fermentation the juice should, when first 

 crushed, be of suitable composition. A gravity of 1.069 oi" 9-3 <^^S- 

 Beaume, corresponding to a resulting alcoholic strength of 15.8 per cent, 

 proof, should ferment out rapidly and completely. This is, as we have 

 seen, the average gravity of Victorian apple juice. Abundant exposure 

 to air prior to or at the commencement of fermentation is verv beneficial, 

 and will insure its being active and healthy. Filtration during fermen- 

 tation is to be avoided, although straining through any coarse tissue, such 

 as hessian, to remove rough impurities in suspension, can do no harm. 



Conversion into vinegar is not likely to be ever applied to high grade 

 fruit. On the contrary, it will be of greatest use as a means of preventing 

 faulty or damaged fruit from going to waste. With such, the addition 

 of a small quantity of tannin to the apple juice prior to fermentation will 

 often be found very beneficial. This will cause the precipitation of 

 albuminoid or mucilaginous substances in the juice and insure an appre- 

 ciable improvement in condition at the close of the first fermentation, 

 thus producing a cider better suited for the healthy growth of the acetic 

 ferment later on. From f oz. to i J oz. of tannin of good quality dissolved 

 in warm water, or preferably in weak spirit, per 100 gallons of apple 

 juice, will be sufficient. More than ij oz. should not be used, and if the 

 fruit is in fair order this quantity may be correspondingly reduced. When 

 the alcoholic fermentation is complete and all sweetness has disappeared, 

 the cider may be filtered or fined; it should, as soon as fairlv clear, be 

 racked into fresh casks. It is now ready to undergo the second part of 

 the process. 



Needless to say, absolute cleanliness must be observed in all manipula- 

 tions. It is just as necessary here as in the making of wine or ordinary 

 cider. The only organisms, the development of which is desired, are the 

 alcoholic and acetic ferments. That of so-called .secondary or parasitic 

 ferments is to be carefully guarded against. These are largely filth 

 organisms and one of the best safeguards to use against their development 

 is cleanliness. 



Sulphur, the fumes of which are of so much value in wine making 

 for preventing the development of noxious organisms, cannot be had re- 

 course to here; its antiseptic action would check the healthy growth of the 

 acetic ferment. It must be very sparingly used, if at all. 



The Acetic Fermentation. — Having transformed the apple juice into 

 cider it would be possible to proceed immediately with the second stage 

 of the process. Before commencing this, however, it will be well to allow 

 it to rest for a certain time, in order that it may become clear, and lose 

 the carbonic acid gas with which it was charged at the close of its alcoholic 

 fermentation. 



Acetification does not take place actively at low temperatures. The 

 best temperature for the development of the acetic ferment is from 86 

 deg. F. to 95 deg. F. (Pasteur). This, however, is not that adopted in 

 the best vinegar works, a superior product being obtained between 68 deg. 

 and 89 deg. Below 50 deg. acetic fermentation is slow and unsatisfactnrv. 



