362 ADULTERATION OF WINE. 



Lead is now never used to adulterate wine. Sugar is 

 often used to mask acetic acid ; but sugar is present in 

 all wine ; it is only therefore by estimating the saccha- 

 rine contents in good wine of the same kind that it 

 can be discovered whether a ponderable quantity of 

 sugar has been added. 



In any case the distillation of the wine gives the 

 excess of free acetic acid. It must not be forgotten 

 that all wines contain a certain amount of free 

 acetic acid which is obstinately retained by the wine 

 extract (p. 244). 



If wine be evaporated, and the extract that remains 

 be found to contain free tartaric acid, no acetate of 

 potash, soda, or lime can be present. 



The presence of alum, which is occasionally added 

 to red wines to heighten their colour, may be ascer- 

 tained by burning the ashes of the wine extract 

 obtained by evaporation. First a larger amount of 

 ashes, next more sulphuric acid, and lastly, more 

 alumina, are found in such wines. 



Lime and common salt have already been mentioned 

 (p. 99). 



Liebig recommends the addition of neutral tartrate 

 of potash in order to free wines from excess of tartaric 

 acid. Cream of tartar is thus formed, which crystallizes 

 and is deposited. Although an adulteration, this 

 method is preferable to any other ; 3*5 grammes (54 

 grains) of this salt were required for 1 litre (1*8 pints) 

 of old wine of 1811. 



