WINE. 



the fermentation, however, be permitted to go too far, this 

 acid will be formed, and hence it occafionally occurs in in- 

 ferior wines. 



2. Extraai-ve and colouring Matters. — Thefe ill-defined 

 fubftances exift more or lefs in all wines. Their properties, 

 however, are not well afcertained, nor are they probably 

 uniformly the fame in every inftance. They have a ten- 

 dency to feparate fpontaneouny, and along with the tartar 

 form what is termed the crujl; hence, as wines become older, 

 from their containing lefs of thefe matters, they ufually 

 become paler. Thefe extraftive matters may be alfo fepa- 

 rated artificially by means of animal charcoal, the fubacetate 

 of lead, and even partially in feme inltances by lime-water, 

 or the heat of the fun. The colouring matter, as we for- 

 merly noticed, is not derived from the juice of the grape, 

 but from its huflt. 



3. EJential Oils Wines, though effentially the fame in 



their general compofition, are diftinguifhed from one another 

 principally by their flavour and odour, no lefs than by the 

 proportion of alcohol they may contain. Now their fenfible 

 properties evidently depend upon fome volatile and fugacious 

 principle, which has been confidered to be analogous to an 

 eifential oil. This principle is fometimes derived imme- 

 diately from the fruit, as, for example, in the wines made 

 from the Frontignac and Mufcat grape. At other times, it 



is the produft of fermentation. Thus the finer flavour* of 

 claret, hermitage, and Burgundy, bear no refemblance to 

 thofe of the grapes, from whence they are formed. Very 

 often, as before ftated, the principles of odour and flavour are 

 communicated to wines artificially, by the introduftion of 

 foreign ingredients, as orris-root, grape, and elder-flowers, 

 mignonette, &c. The menftruum of this volatile principle 

 is doubtlefs, in moft inftances, the alcohol contained in wines ; 

 but its quantity is fo minute as to be incapable of fepa- 

 ration. 



4. Akohol. — The charafteriflic ingredient of wines is 

 alcohol. Indeed, wines may be confidered as more or lefs 

 dilute folutions of alcohol, impregnated with different 

 flavouring fubftances, and a little acid. There have been great 

 differences of opinion in what ftate alcohol exifts in wines. 

 Some chemifts maintain, that alcohol does not exift ready 

 formed in wines, but that its elements only exift in a pecu- 

 liar ftate, and that their union is determined, and confe- 

 quently alcohol formed, by the aft of diftillation. This 

 opinion was advanced by Fabroni, and feenis to have been 

 adopted by fome fubfequent writers. Mr. Brande, how- 

 ever, has fliewn by very decifive experiments, that all wines 

 contain alcohol ready formed, and that this fluid is merely 

 feparated during the diftillation of thefe liquors ; and his ex- 

 periments have been fince fully confirmed by Gay Lnflac. 



I 



The following Table, reprefenting the Quantity of Alcohol and other Principles in different Wines, is taken from 

 Dr. Thomfon's Chemiftry, though it was compiled originally by Neumann. The refults are not abfolutely to be 

 relied upon, as the ftate of chemical Knowledge, at the time Neumann wrote, was very imperfea. 



The 



