The operation of racking the wine will presently be considered, but a few words must first be devoted to the " fortification" of wines, and the results to be expected from it.
eonsists in introdueing a certain proportion of alcohol into the wine for the purpose of strengthening and preserving it, the aleohol opposing secondary fermentation by paralyzing the action of the ferment and preeipitating the albumineid matters ; it also improves the condition of weak and acid wines. The operation may be performed either in the vat or in the casks, preferably the former. The must is fortified by addiug a proportion of sugar corresponding to the alcoholic strength desired, or by adding alcohol itself when the fermentation is approaching its end, or about twelve to fifteen hours before racking. Wine in the cask is fortified by an addition of alcohol or by a mixture with very alcsoholic wines. The wine may also hesubmitted to coagelation, which removes a portion of its water in the form of ice. Fortification sweetens too acid wines, in that the alcohol precipitates the exoess of cream of tartar, and eombines in time with the free acids present to form ethers. It also affects the colour of red wines, alcohol being a solvent of the violet principle of the grapes. The colour of the wine is due to a mixture of this normal violet with a red colour due to the effect of the air and acids. It therefore follows that better results on this head are obtained by fortifying in the vat, for by direct fortification in the cask the red tint is diminished and preeipitated in the lees.
It is evident then, that independently of its direet aetion, aleohol de-aeidizes too acid wines, favours the formation of ethers, increases the eolour, and gives a body to the wine. These are sufficient reasons in its favour ; but the direct addition of alcohol must almost always be condemned. Not only are the most detestable compounds brought into the market after treatment with alcohol, but the plan has also this great diss.dvantage, that wines so treated cannot possess the.t degree of honzogeneity which arises from fermentation, and which is one of the principal merits of natural wine. Ill-advised, however, as the direct addition of alcohol is, it is, nevertheless, only too often resorted to, because the cost of the alcohol produced by fermenting additional sugar in the must is a trifle higher than the commercial price of manufactured alcohol. It does occasionally happen, however, that good may result from the addition of alcohol t,o the must towards the end of the fermentation in the vat.
Eaching.—From the preceding observations it is evident that the moment for racking wine cannot be submitted to fixed stnd invariable rules, but that it will differ with the climate, the season, the quality of the grapes, the nature of the wine to be produced, and other considerations which must not be lost sight of. The sinking of the head is not a sufficient sign, as some wines should he drawn off before this happens, wtile others improve hy remaining for some time afterwards. The cessation of sparkling and froth, indications drawn from the odour, taste, colour, cooling, and density, do not always form a safe guide, though the last mentioned does, in the majority of cases, mark the precise moment. Wines for distillation must he thoroughly fermented ; while weak, perfumed wines need less, notably some white wines whose speciality is to be sparkling. Racking must invariably he performed when the sweet taste has become insensible, and is replaced by a vinous flavour. The lowering of the density to 0° or 1° B., cannot always be considered a proof of the end of the fermentation, since the proportion of alcohol s.nd other matters renders it inconstant. Chaptal gives the following rules:— 1, The must should ferment for a length of time proportionate to the sugar it contaios ; 2, It should ferment less for sparkling wines, and be introduced into the casks immediately after pressing; 3, It should ferment less as the colour is weaker ; 4, It should ferment less as the temperature is higher s.nd the map greater ; 5, It should ferment less EIS the wine is to he more perfumed ; 6, It should ferment longer if it is to be distilled ; 7, It should ferment longer as the temperature was lower at the time of vintage ; 8, It should ferment longer as the wine is to be more coloured ; 9, And it should ferment longer in small vats than in large. Consequently the vatting may vary from 24 hours to 12 or 15 days. Nothing is more arbitrary in practice than the moment for retcking, but there is no doubt it may take place the instant the active fermentation ceases, and the vatting need never he prolonged beyond 72 hours for very rich wines, and 30 to 36 hours for delicate wines ; while the latter period much more than suffices for very light wines or those for immediate consumption.