Another, and perhaps still more important consideration, is that there is much less loss by evaporation when the wine is stored in large casks. The evaporation in a small barrel will be almost as great as in a cask three or four times the size, and to keep the small one full will require about the same amount of wine at each ulling, which must be performed nearly as often. There are two reasons for this: first, because the staves of small casks are thinner, and secondly, because in them a greater surface of wine is exposed to evaporation, according to the volume, than in the case of the larger vessel.
Guyot says, however, that the larger the receptacles, other conditions being equal, the more rapid the development of the wines, and the sooner they go through the periods of their life, and arrive at decrepitude. He says that the greater part of wines, especially light wines and white wines, cannot endure a long sojourn in tuns, vats, and cisterns. They go through the phases of their life with a rapidity fatal to their good qualities; nevertheless, this fact may be utilized to hasten the epoch when wine may be used or put upon the market; also to produce dry wines, to vinify sweet ones, and to age those of good body. If, therefore, his theory is well founded—and we know that fermentation once established is more active, if the mass is great—the intelligent man will act in this behalf as circumstances require. It would seem, however, that a large mass would be less affected by sudden changes of temperature, and therefore, better protected from their consequent ill effects.
And Boireau recommends that white wines be stored in tuns, when mature, as already mentioned. (See [Aging].)
CHAPTER IX.
SULPHURING—ARRESTING
FERMENTATION.
Casks are sulphured for the purpose of destroying the activity of the ferments contained in the lees which may remain in them, and thereby to prevent their moulding or souring, and must and wine are sulphured to prevent or to check fermentation, and white wine also to keep it from turning yellow.
Sulphurous Oxide, or Sulphur Dioxide, is produced by burning sulphur. It is a colorless gas, of a suffocating odor, and is composed of equal weights of sulphur and oxygen, or, one part of the former and two of the latter, SO₂, and with water becomes sulphurous acid. It arrests fermentation in two ways: first, it absorbs oxygen with avidity, and thereby removes what may be in the must or wine, or in the cask, thus taking away one of the conditions necessary to the life and activity of the ferment. (See [Fermentation].) In the second place, by the absorption of oxygen, sulphuric acid is formed from the sulphurous acid, in a highly concentrated state, which is destructive of the life of the ferment.
Fig. 13.
Sulphurer.
Fig. 14.