Sulphming.—This operation consists in burning sulphur in the casks. Its first effect is to make the wine thick and its colour disagreeable, but the latter returns in a short time, and the wme clarifies itself. Its object is to prevent acidification and all ulterior fermentation. It also displaces the air.
Wines are sometinaes sulphured without being withdrawn from the cask. A small quantity is drawn off, and the sulphured wick inserted at the bung-hole and burned just above the surface of the wine. 'While the enopty portion of the cask is filled with the sulphurous gas, the bung is replaced, and the cask agitated violently, in order that the gas may be entirely dissolved. The cask is then refilled with wine. Another method of sulphuring wine consists in introducing a small quantity of a aolution of the sulphurous gas in water.
Clarification.—The processes of racking-off and sulphming remove a•large portion of the im pmities of a wine, but there still remain particles of suspended matter, which must be precipitated by a process of artificial clarification. This process not only removes suspended matters but aids in precipitating dissolved impurities, even after a considerable lapse of tiroe. Hence it constitutes a powerful means of improving and preserving wines, and cannot possibly be dispensed with. The substances most commonly employed to effect this clarification are fish gelatine, the whites of eggs, blood, and various other substances artificially prepared. When fish gelatine is employed, it should be chopped into small pieces and stirred up with a little wine and an equal weight of tartaric acid ; it swells, softens, and forms glutinous mass. This is thrown into the wine in small quantities and with much atirring, after which the wine is left' to stand. Dining this time, the gelatine combines with the tannin of the wine and falls to the bottom, carrying with it all particles of suspended matter, and leaving the wine clear and .bright. Five grammes of fish gelatine is sufficient to clarify 150 litres of wino. To prepare it for use, 5 grtn. may be dissolved in 71 decilitres of white wine and made up to tbe litre with brandy; this preparation will keep indefinitely if kept tightly corked. In warm climates, egg-albumen may be used with advantage in winter ; the whites of five or six eggs are sufficient to clarify 150 litres of wine. They are
beaten up with a pinch of salt, and then thrown into the cask. Eggs which are not absolutely freah muat not on any account be employed. Blood-albumen may be substituted either for fish gelatine or white of eggs ; one portion is coagulated by the alcohol, and the rest combines with the tannin and colouring matters of the wipe. Its use tends greatly to iroprove the colour of the wine, especially if its colour has become altered by age. In order to preserve blood, it may either be mixed with an equal portion of alcohol at 58°, or it may be dried. Many different powders, consisting of albumen in various forms and bearing particular names, are prepared and vended in France as clarifying powders.
Classifration of may be divided into several different classes, accorcling to the point of view from which the classification is regarded. The most obvious division is that of colour : they may be either white or red. White wines are prepared from both white and black grapes, but the juice after expression is not allowed to remain in contact with the skins and seeds of the black variety, or it will extract the colouring matter. Red wince are made from the black grapes only, and the must is allowed to lie upon the seeds and skins until it has become of the desired colour. Or wines may be classed again as " sparkling" or " still" wines. The qualities of sparkling wines are afforded to them by placing iu the bottles a little and so causing them to undergo a second fermentation; still wines are those which have not received this addition of sugar. A very common classification of wines is as " dry " or " fruity "; the former being thoae, like Rhenish winea, which contain little or no free sugar, and the latter those, like port and sherry, which contain much sugar and have a sweet or " fruity " flavour. Wines may be further spoken of as simple or compounded, or mixed, the latter being, of course, mixtures of two or more simple wince made for the purpose of blending their distinctive qualities of taste, bouquet, and colour. Such mixturea are much drunk in this country.