PREPARATION OF CIDER AND FRUIT-WINES. 325 



purified animal charcoal,* boil the mixture about five minutes, 

 and after cooling replace the exact quantity of water lost by 

 evaporation. After shaking bring the whole upon a coarse 

 paper, filter in a glass funnel, and let it run off. Of the clear 

 and generally colorless filtrate bring 6.7 cubic centimetres into a 

 small beaker, add sufficient distilled water to form a layer of 

 fluid 2 to 3 centimetres deep, and color red with 5 to 10 drops of 

 litmus tincture. While holding the beaker in the left hand and 

 constantly moving it slowly in a horizontal direction alloAV to 

 run or drop in from a pipette graduated in ^ cubic centimetres 

 and filled to the O mark, decinormal liquid ammonia until 

 the last drop no longer changes the color of the fluid and the 

 place where the drop falls appears as if made clear by a drop of 

 water. Now prevent a further flow of the ammonia by closing 

 the pipette with the index finger of the right hand, and read off 

 the quantity of ammonia consumed. The must examined con- 

 tains as many thousandths of malic acid as cubic centimetres of 

 liquid ammonia were required to color the fluid blue. 



Now if the examination shows that a must contains more than 

 8 parts of acid per thousand, it is evidently too sour for the 

 preparation of a palatable and wholesome fruit wine, and hence 

 must be diluted to such degree as to reduce the content of acid to 

 6 or at the utmost to 8 parts per thousand. The calculation for 

 this dilution is very simple, and consists in multiplying the acid 

 per thousand parts present by 100 and dividing with the content 

 of acid the wine is to have, the entire volume containing the de- 

 sired acid per thousand being thus obtained. If, for instance, 18 

 parts per thousand of acid have been found in currant-must and 



-j rj/"i vIS 



the wine is only to show 6J parts per thousand, then 



= 276.923, in round numbers == 277, i. e., 277 parts by measure 

 of water have to be added to every 100 parts by measure of 

 must. 



The content of acid in the must thus forms the initial point 

 for the dilution in order to obtain, after fermentation, wine with 



* Bone-black which is first boiled with solution of sodium carbonate for 

 some time, and then after washing and extracting with hydrochloric acid is 

 again washed and dried. 



