WINE-MAKING

Field, Forest and Farm by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here. WINE-MAKING

CHAPTER XLIV. WINE-MAKING

“When wine is heated, there is first an escape of an inflammable vapor that burns with a bluish flame. A person needs only to have seen once this preparation of hot wine to recall that curious flame flickering over the boiling liquid and darting up little blue tongues. Now, this inflammable vapor comes from alcohol, a fluid substance that gives to wine its peculiar properties and is hence sometimes called spirits of wine. There are, then, in wine two distinct liquids, one easily reducible to vapor and called alcohol, the other slower to vaporize and recognizable as water. This does not mean that the wine has been watered: the water in question is not there as the result of fraud; it belongs naturally to the wine and comes from grapes just as alcohol does. Wine is therefore a natural mixture of a small proportion of alcohol with a great quantity of water. In our ordinary wines the proportion of alcohol for each hundred quarts of liquid varies from nine to fourteen quarts.

“Wine is made from the juice of grapes. This juice, as it is pressed out of the sweet grapes, has none of the taste or smell peculiar to wine, for it does not yet contain any alcohol; but it does have an [224]agreeably sweet taste, the same taste that makes grapes so desirable a fruit for the table. This pleasant flavor is due to a sort of sugar present in the grapes. Examine carefully a handful of raisins such as you buy at the grocer’s: you will detect on their surface, certain tiny white grains that crunch under the teeth and have a sweet savor. Those grains are little particles of sugar that have collected on the outside of the grapes during the process of drying. Grapes, then, must contain sugar.

“Well now, this sugar is exactly what causes the formation of alcohol. What is sugar in the fresh juice of grapes is alcohol in the same juice after it has fermented and turned to wine. Let us consider briefly how this change comes about.

“The vintage is first of all subjected to a process of treading by men who trample on the grapes in large vats, after which the resulting mixture of juice and skins is left to ‘work,’ as we say. Before long this liquid mush begins to heat of its own accord, and presently there sets in a sort of boiling which liberates big bubbles of gas as if there were a fire underneath. This working process is called fermentation, and its seat is in the sugar of the grape-juice. Little by little the sugar decomposes, splits apart as we might say, into two substances very different from each other and also very different from the sugar whence they came. Of these two substances one is alcohol; the other is a gas already known to us—carbonic acid, the same gas that plants feed on and that animals give forth in breathing; [225]the same, finally, as that produced by burning coal. The alcohol remains in the liquid, which thus gradually loses its original sweet taste and acquires instead a vinous flavor. The gas, on the contrary, works its way to the surface, agitating the mass with a sort of tumultuous movement like that of boiling water, and is dissipated in the atmosphere.

“Let us bear in mind that carbonic acid gas is as invisible as the air itself, that it has no odor, no color, and finally that it kills quickly if inhaled in any considerable quantity. That explains the danger lurking in a wine-vat during fermentation, or even in a wine-cellar that lacks sufficient ventilation to carry off the perilous gas. No one should enter such places without holding before one a lighted taper at the end of a long stick. While the taper continues to burn in the usual manner, one can proceed without fear: there is no carbonic acid gas present. But if the flame becomes dim, gets smaller and smaller, and finally goes out altogether, one must beat a hasty retreat, for the extinction of the taper is a sure sign of the presence of carbonic acid gas, and further advance would mean exposing oneself to imminent death.

“But to return to the subject of wine-making, we were saying that the sugar which imparts its sweet taste to the must (that is, the unfermented grape-juice) changes its nature and divides into two parts: alcohol, which remains in the liquid and turns it to wine, and carbonic acid gas, which is dissipated in the atmosphere. When this process is [226]finished the wine is drawn off, leaving behind the residuum of skins and pips. The final product is thus composed of a large quantity of water from the grapes themselves, a small quantity of alcohol from the sugar which has undergone the chemical change just described, and, finally, a coloring substance furnished by the dark grape-skins.

“White wine is made from white grapes, which have skins with no coloring matter; but it can very well be made from dark grapes, colored though they are. The secret consists simply in this: the crushed grapes are pressed before fermentation begins. In this way the juice is separated from the skins, and, these latter being removed, the wine will be white even with dark grapes. In short, the coloring matter in grapes which gives its hue to red wine is contained solely in the skins; and furthermore it is insoluble in water, but easily soluble in alcohol. Hence it is only after fermentation has made some progress that the liquid becomes colored by the dissolving of the coloring matter through the agency of the alcohol that has been generated. Accordingly, if the skins are removed before the juice ferments and generates alcohol, the wine remains white, since it no longer contains any coloring matter to dissolve.

“Some wines force out the corks from their bottles and are covered with foam on being poured into glasses. These are foamy wines, and to produce them the bottling must be done before fermentation is finished. The carbonic acid gas then continues to form, but as it finds no way of escape since the [227]bottle is tightly corked, it dissolves in the liquid and accumulates there, though all the while endeavoring to free itself; and that is what makes the cork pop with a sharp report when the string that holds it down is cut; that is what causes the wine to rush foaming out of the bottle; and, finally, that is what gives the bead to a glass of wine and makes a slight crackling sound as the bubbles burst on the surface.

“Foamy wine has a pungent but agreeable taste owing to the carbonic acid it contains. We drink, dispersed through the liquid, the same gas as would kill us if freely inhaled; but it has no terrors except when thus inhaled. Mixed with our drinks, it imparts to them a slightly tart flavor, harmless and even salubrious, since it aids digestion. There is carbonic acid gas in nearly all water that we drink, and it is in fact by reason of this gas that water is able to hold in solution the small proportion of stony matter that contributes toward the formation of our bones. It is to this gas, finally, that effervescent lemonade, cider, beer, and Seltzer water owe their pungency and their foam.”

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