The Chemistry of Wine. 



15 



we can not call the wine finished. In 

 olden times many means were employed 

 to extract the superfluous gluten, and 

 very often kept as secrets : such as ad- 

 ditions of lime, salt, etc. A more ra- 

 tional method is the process of sulphur, 

 ing the casks, before fermentation com- 

 mences, which is generally adopted in 

 Champagne, for those musts from which 

 spai'kliug wines are made, as it is of the 

 utmost importance in sparkling wines 

 that the}' should not contain any fer- 

 menting substances ; because these 

 would either burst the bottles, or make 

 the wine cloudy. 



It is also adopted on the Rhine, 

 for red wines, and the result is an 

 excellent wine, which will keep very 

 long. 



All these manipulations are super- 

 fluous, however, if all ingredients are 

 contained in the must in due propor- 

 tions ; and where it does not contain 

 them naturally the missing substances 

 may be added — a subject to which we 

 shall in due time return. 



To divest the wine of gluten, after fer- 

 mentation, there are also many meth- 

 ods, which, however, should be applied 

 with great caution. Among these are 

 oxydization by air treatment, heating 

 etc. , which will be fully discussed in their 

 proper places. 



Additions of chemicals, such as sul- 

 phate of lime, so often used in refining 

 of cider, etc., are very injurious to wine, 

 and should not be used. Those meth- 

 ods of fining wine, which are now so 

 common in use, as gelatine, isinglass, 

 filtration, etc., dispose only of those 

 substances which have already become 

 insoluble, and which are apparent to the 

 eye. Wine which has thus been clari- 

 fied will become cloudy again, as long 



as it contains dissolved fermenting sub- 

 stances. The method to clarify wines 

 by exposing them to cold, leads to 

 somewhat the same result. If the tem- 

 perature is reduced to about from 40° 

 to 25° F., young wines will not ferment 

 any further. The insoluble particles of 

 gluten yet dispersed in the wine will 

 sink to the bottom. At the same time, 

 however, nearly all the tartar, which 

 would be deposited later, as insoluble, 

 is now cast out. Thus it comes, that 

 wines which were bottled in a warm 

 temperature will deposit tartar, and with 

 it gluten, when they are put into a cold 

 cellar, although they may have appeared 

 perfectly clear. If they are removed to 

 a warmer temperature again, the deposit 

 will dissolve again, and the wine be- 

 come clear. 



Although it must therefore be ad- 

 mitted that the cooling of wine, or its 

 storing in cool cellars, is of use, as far 

 as it facilitates the deposit of tartaric 

 acid, the benefits derived from it are 

 still not important enough to justify the 

 building of expensive cellars, especially 

 as the wines grown in many sections of 

 this country contain but little crystal' 

 lized tartaric acid, in the form of tartar, 

 but mostly free acids. The greatest 

 quantit}' of tartaric acid, in its crystal, 

 lized form, is contained in California 

 wines, which may almost be called a 

 saturated solution of tartar. The more 

 kali a certain soil contains, the greater 

 will be the amount of tartar in the 

 grapes grown on it ; Avhile those grapes 

 grown on soil which contains but little 

 kali have more free acid, which is more 

 perceptible to the taste. 



To he Continued. 



