ADULTERATION OF WINE. 373 



and as soon as the wine has been long enough in the 

 cask to get clear it is bottled off. 



Deyeux recommends the following method of de- 

 tecting adulterations effected by means of cider and 

 perry : The wine is evaporated in order to allow the 

 cream of tartar to crystallise ; the process is repeated 

 as long as any of this salt deposits. The taste of the 

 residue is like that of apples and pears; and the 

 smell of apples and pears is distinctly perceived if the 

 extract be thrown upon a coal fire. The same result 

 is obtained if sulphuric acid be added. 



Neither tartar nor tartaric acid is found in cider 

 and perry the absence of these substances is a sign 

 that the liquid contains no grape-juice. The adulte- 

 rator may however know this, and add the necessary 

 amount of cream of tartar to the cider or perry. In 

 any case the fraud may be detected by warming with 

 ammonia, and adding acetate of lime ; for tartrate of 

 lime is insoluble, citrate of lime is soluble, in ammonia, 

 but may be precipitated, if warmed with ammonia 

 whilst alcohol precipitates malate of lime from the 

 filtered liquid. 



Cider contains a large amount of tannic acid, and is 

 prepared from sweet apples. It is well known that if 

 sweet apples be cut with a steel knife, the blade will 

 speedily furnish tannate of iron (ink) ; also that the 

 tannic acid of sweet apples when brought into contact 

 with air is rapidly converted into apothema, so that 

 peeled apples quickly turn brown. Sweet apples when 



