"Y OU will be surprised to hear," said Uncle Paul, "that any sweetened substance will generate alcohol by a remarkable chemical change called fermentation, and that alcohol in its turn changes into vinegar. As sugar is the origin of alcohol, it is sugar, in reality, that makes vinegar. Here we see something generating its opposite, sweet giving birth to sour."
"The same thing happens," Marie observed, "with milk or with a slice of melon: they both sooner or later lose their sweet taste and turn sour."
"Those are two good examples of substances which, at first sweet, turn sour as soon as decomposition sets in; but vinegar such as is used in cooking goes through a little different process; for it comes not directly from sugar but from alcohol. All alcoholic liquids are good for making vinegar; nevertheless wine makes the best and most highly valued. The very word vinegar shows you how the thing itself is made, 'vinegar' meaning nothing more nor less than 'sour wine'—vin aigre."
"Why, so it does!" Claire exclaimed. "I hadn't noticed it before. The two words fit together just right; not a letter too many, and not a letter too few."
"In wine," Uncle Paul resumed, "it is the alcohol, and the alcohol alone, that turns sour. That is to say, you can't make good vinegar without good wine. The more generous the wine, or, in other words, the richer it is in alcohol, the stronger the vinegar. People often make a mistake on that point: they think that poor wine, the final drippings from the wine-press, the rinsings of bottles and casks, will in course of time take on sufficient sourness. A great mistake. Such watery stuff cannot possibly yield what it does not possess. As soon as the small proportion of alcohol it contains has turned to vinegar, that is the end of it; no matter how long you wait, there will be no increase of sourness. The rule has no exceptions: to obtain good vinegar use good wine, wine rich in alcohol."
"But you haven't told us yet," said Jules, "what must be done to change the wine into vinegar."
"That takes care of itself. Leave on the kitchen sideboard an uncorked bottle of wine, not quite full, and in a few days, especially in summer, the wine will turn to vinegar. On the express condition of its being exposed to the air, wine will turn sour of itself, and all the quicker when a warm temperature hastens the process of decomposition in the alcohol. That shows you at once the care necessary for keeping table wines and preventing their turning sour. If in bottles or demijohns, they must be tightly corked with good stoppers, since otherwise air will get in and the wine will be in danger of souring. As cork is always more or less porous, the top is covered with sealing-wax when the wine is to be kept a long time; in a word, the bottles are sealed."
"Then it's just to keep out the air," said Emile, "that they seal the bottles with red, green, black, or any other colored sealing-wax?"
"Merely for that reason. Without this precaution air might gradually get into the bottle, and when it was uncorked, instead of excellent old wine, you would have nothing but vinegar. You see, if you wish your wine to keep well, you must, above all, guard it from the air. A partly filled demijohn or cask, opened every day to draw out wine and then carefully recorked, soon goes sour, especially in summer. If the wine is not likely to be all used up for some time, the contents should be bottled and carefully corked. In that way the wine is in contact with the air only one bottle at a time, as it is called for, and so cannot turn sour provided it has been properly corked.
"Let us, then, accept it as a rule that if wine is not to turn sour it must come in contact with the air as little as possible. If, on the contrary, we wish to change it into vinegar we leave it exposed to the air in uncorked or imperfectly corked vessels. Little by little, through the long-continued action of air, its alcohol will turn sour. That is what happens to the remnants of wine left in the bottom of bottles and forgotten.
"Of all the seasonings used with our food, vinegar, next to salt, is the most prized. With its cool, tart flavor and agreeable odor it gives a relish to dishes that without it would be too insipid. Its use is not only a matter of taste, but also of hygiene, for taken in moderation it stimulates the work of the stomach and makes the digestion of food easier. Combined with oil it is an indispensable seasoning for salad. Without it this raw food would hardly be acceptable to the stomach."
"That is one of my favorite dishes," Jules declared, "especially when it is made of spring lettuce; the vinegar makes it taste so good, pricking the tongue just enough and not too much."
"Vinegar is also used in the preparation of certain well-known condiments—capers, for example."
"Oh, how I like them!" cried Emile, "those capers they sometimes put into stews. Where do they come from?"
"I will tell you. In the extreme south of France, near the Mediterranean, there is cultivated a shrub called the caper-bush. Its favorite haunts are rocky slopes and the fissures in old walls and rocks much exposed to the sun. Its branches are long and slender, armed with stout thorns. Those branches bend over in a graceful green mass, and against the darker background of foliage are set off numerous large and sweet-smelling pink blossoms resembling those of the jasmine. Well, these blossoms, before they open, are capers. As little buds they are gathered every morning, one by one, and pickled in vinegar of good quality. That is all that is done to them. So when Emile smacks his lips over the caper sauce, he is eating nothing more nor less than so many flower buds."
"I shall like them all the better for knowing they are flowers," the boy declared.
"In like manner gherkins are pickled in vinegar. They grow on a vine much like the pumpkin-vine. Similar treatment, too, is given to pimentos, sometimes called allspice on account of their spicy taste, which becomes unbearably strong when the fruit is ripe and coral-red. I will remind you that all pickling with vinegar should be done in vessels not glazed on the inside with lead. I have already told you that ordinary pottery is glazed with a preparation that contains lead. Strong vinegar might in the long run dissolve this glaze and thus acquire harmful qualities. Keep your capers, pimentos, and gherkins in glass vessels, or at least in pots that are not glazed inside.
"In conclusion I will tell you that vinegar has the property of making meat tender. To insure tenderness in a piece of beef it is sprinkled several days in advance with a little vinegar to which have been added salt, pepper, garlic, onions, and other seasoning, according to the taste of each person. In this mixture, however many of these ingredients there may be, vinegar plays the chief part. This process is called sousing the meat."
It is a little strange that although excellent cider is produced in France, especially in Normandy, it seems not to be used for making vinegar.—Translator's Note.