Vinegar is truly an outstanding example of the harmony between science and cooking, even just in terms of its preparation. Vinegar comes from alcohol that has been fermented with the fungus Mycoderma aceti, similar to the one responsible for levitation. Most commonly, the “mother of vinegar” is used in the form of a gelatinous mass, enriched with this fungus, from which is taken just the outermost layer (the interior part may actually ruin the vinegar). Once this fungus is placed into wine, it provokes a series of complex chemical reactions: oxygen molecules attach to the alcohol and form acetic acid. Wine is then completely transformed into this acid.
From a practical point of view, making good vinegar isn’t difficult. First of all, you’ll need two liters of wine (with a maximum of 10% alcohol and low in sulfites), a very clean, large demijohn and some gauze. Pour the wine into the demijohn and then cover it with gauze. Put in in a dark place whose temperature is between 25°-30°C and wait for at least 40 days. At this point, a spongy substance will have formed: this is the fungus that creates the mother vinegar. Remove a half liter of liquid (which is already vinegar) and pour another half liter into the demijohn.
Each month, you can remove another half liter of vinegar and substitute it with more wine. It’s best to wash the mother vinegar each year: just empty out all of the vinegar, wash the demijohn and put the liquid back in, straining it. This is the procedure to follow with wine, but you can make excellent vinegar with fruit juice from apples, pears, berries, grapes and honey. Of course, you can also add different aromas to your wine vinegar: common herbs are rosemary, juniper and tarragon.
What about balsamic vinegar, you ask? Making balsamic vinegar is a bit more complex: you must begin with high-quality white grapes. As soon as the must begins to ferment, it must be boiled slowly, then cooled and then put into barrels to acetify. As the liquid concentrates, it should be placed into smaller and smaller barrels made from different woods and with various aromas until it becomes the precious delicacy known as balsamic vinegar. And we know why it can be so costly: some versions take more than 20 years to produce!
Vinegar can be used in a dizzying range of ways, and allows for a lot of culinary experimentation. It’s often used in marinades as its strong acidity helps to “cook” raw foods, turning fish meat, for example, from clear to opaque in little time. Then there’s the famous “vinaigrette” dressing made with oil, vinegar and salt—perfect for vegetables.
One last tip before embarking on your own vinegar-making adventure: start with good wine. Low-quality wine will make low-quality vinegar, and some may not even acetify.