1146 WINE 



Liebig, in his ' Organic Chemistry,' has the following remarks on the bouquet : ' It is 

 well known that wine and fermented liquors generally contain, in addition to alcohol, 

 other substances which could not be detected before their fermentation, and which 

 must therefore have been formed during that process. The smell and taste which 

 distinguish wine from all other fermented liquids are known to depend upon an 

 ether of a volatile and highly combustible acid, which is of an oily nature, and to 

 which the name of ananthic ether has been given.' 



On the Ehine an artificial bouquet is often given to wine, by hanging orris-root in 

 the casks, or by the use of aromatic herbs. 



The volatile substance existing in wine which imparts to it, conjointly with 

 ccnanthic ether, its vinous aroma, is partly alcohol. There are other odoriferous 

 substances developed in the course of time ; these are compounds of oxide of ethyl, 

 amyl, or propylene, with acetic, propionic, pelargonic, butyric, caproic, caprylic, or 

 capric acids. Acetic ether is present in all aromatic wines, and fraudulent dealers will 

 add acetic ether in small quantities to their artificial compounds. 



Butyric ether is much used by confectioners, who call it 'pine-apple oil.' Caprylic 

 ether has a similar flavour ; these are slowly developed in some wines by time. In 

 Watts's ' Dictionary of Chemistry' the other chemical comp9unds will be found fully 

 described. 



Wine produced from grape-juice alone is perfectly colourless or white ; but as the 

 whole mass of the grapes is pressed together, it is impossible .but that some admixture 

 of the components of the grape-skins should occur. White wine may be prepared from 

 purple grapes, but if the skins are allowed to ferment, red or yellow wine will be 

 obtained. The Italian wine, Vino Cebedino, is about the most colourless of wines. 



The colour in wines appears to be due to the presence of extractive matter, which, 

 when oxidised, assumes a red or brown colour. This colouring-matter has been 

 called apothema by Berzelius, but it is, in fact, humic acid, retaining traces of the sub- 

 stance from which it has been derived. 



Whilst the juice of grapes ferments, the skins being present, the wine which is 

 in process of formation extracts tannic acid from the skins, and this gives the yellow 

 colour when by oxidation it is converted into apothema to Muscadel, Champagne, 

 Teneriffe, and Madeira. 



What we call Eed wines are prepared from either black, purple, or red grapes, the 

 juice of which is colourless, and the skins of which are allowed to ferment. During 

 fermentation the weak spirit which is formed extracts not only tannic acid but blue 

 colouring-matter from the skins. This blue colouring-matter is tinged more or less 

 red by the tartaric acid of the wine, and may afterwards be rendered more decidedly 

 red by the formation of acetic acid. In the change of colour undergone by 

 red wine, five periods, according to Mulder, must be distinguished. As soon as 

 alcoholic liquid is formed during fermentation, blue colouring-matter begins to be 

 extracted from the skins. As the small amount of blue colouring-matter is brought 

 into contact with grape-juice, which has an acid reaction, it becomes red. The 

 fermentation and formation of alcohol proceed, as does also the solution of blue 

 colouring-matter, and the young wine is rather blue than red, and may be called ' dark 

 violet.' This new wine now undergoes fermentation, during which a great deal of 

 colouring-matter and red tartar, as well as apothema of tannin and albumen, is preci- 

 pitated. The loss of the colouring-matter causes the wine to become lighter. In the 

 meantime the formation of acetic acid begins, and at a later period increases; the 

 amount of colouring-matter is not thereby diminished, but the larger proportion 

 of acid in the liquid reddens its colour. Another period now begins, during which 

 the tannic acid is slowly converted into apothema, .whereby red colouring-matter 

 is again precipitated out of the liquid, for example, in Port wine; it thus gradually 

 diminishes, and finallv, after a length of time, disappears entirely from the wine, 

 which then remains what is called ' yellow.' This will explain the alterations pro- 

 duced by keeping wines. 



According to the character of the wine, as already stated, is its power of enduring 

 unchanged, or of improving by age. Weak wines of bad growths ought to be consumed 

 within twelve or fifteen months after being manufactured ; and should be kept mean- 

 while in cool cellars. White wines of middling strength ought to be kept in casks 

 constantly full, and carefully excluded from contact of air, and the racking off should 

 be done as quickly as possible. As the most of them are injured by too much fermen- 

 tation, this process should be so regulated as always to leave a little sugar undecom- 

 posed. It is useful to counteract the absorption of oxygen, and the consequent tendency 

 to acidity, by burning a sulphur-match in the casks into which they are about to be run. 

 This 5s done by hooking the match to a bent wire, kindling and suspending it within 

 the cask through the bung-hole. Immediately on withdrawing the match, the cask 

 should be corked, if the wine be not ready for transfer. If the burning sulphur be 



