Vinegar—The Tangy Acid
By Awake! correspondent in France
The use of vinegar dates back a long time. Roman legions drank a mixture of vinegar and water. Their name for vinegar was acetum.
WE TODAY use the term “acetic acid” to describe vinegar’s key element, as vinegar is obtained by the acetic fermentation of alcoholic liquids such as wine.
Our English word “vinegar” comes from two French words: vin (wine) and aigre (sour). But just how does wine become sour and turn into vinegar?
A Product of Bacteria
If you leave an opened bottle of wine in a warm room for several weeks, a film forms on the wine’s surface. That film is made up of closely packed cells, microorganisms that are present in the air. They have settled on the wine because it is a good environment in which to multiply.
Let’s taste a drop. How disappointing! Our wine has fermented and is now sour. It has turned to vinegar. What caused it to sour? A microscopic creature called Acetobacter aceti. You can offer him any amount of wine, ale, or cider; and as long as it does not contain more than 12 percent alcohol, he thrives.
Scientists qualify him and his family as aerobes, meaning that they cannot survive without oxygen. That is why this tiny individual can work only at the surface of the liquid, for if he sinks, he will die of asphyxia. That would end the process of converting the alcoholic beverage into vinegar.
Acetobacter aceti and his friends get together in such large numbers on the wine’s surface that they form a slimy membrane called mother of vinegar. Sensitive to cold, a temperature of about 86 degrees Fahrenheit [30° C.] suits him ideally.
Now that you know a little more about vinegar, let’s visit a traditional vinegar factory in Orleans, the capital of the vinegar industry in France.
The Orleans Process
We enter an enormous warehouse containing casks, barrels, and vats of all shapes and sizes. Some are made of oak and others of stainless steel. A number are used to stock the wine as it arrives. This is where the master vinegar-maker mixes and blends his vintages and adjusts the alcohol content to 8 or 9 percent. Other containers serve to stock and mature the vinegar. Lastly, we come to the most important part, where 60-gallon [225 L] barrels are used to transform wine into vinegar.
The huge barrels are set up on their sides in rows. This allows for a maximum surface of the liquid inside to be exposed to air. Air enters through the “eye,” or small hole, toward the top of the barrel. This hole also enables the vinegar maker to check on fermentation. To allow for all of this, the barrels are filled to only four fifths of their capacity. The wine is poured in at a temperature of about 86 degrees Fahrenheit [30° C.], and a small amount of vinegar bacteria is added. The bacteria go to work, and three to four days later, mother of vinegar covers the surface of the wine.
Within two to three weeks, the first batch of vinegar is ready. About 50 quarts [50 L] are drawn off through the spigot near the bottom of the barrel. This is replaced with the same amount of wine, care being taken not to break up the film of bacteria on the surface.
About three weeks later, the same amount of vinegar can be drawn off again, and so forth. Using this method, an average of two or three quarts [liters] of vinegar per barrel are produced daily. This may seem little, but the factory we are visiting has 2,500 barrels, bringing the annual production to several hundred thousand gallons.
Various other processes are now necessary, depending on the quality desired. For instance, impurities are eliminated and the vinegar is filtered in order to clarify it. The vinegar is then aged in huge oak barrels for several months. Then it is put into bottles and sent all over the world.
The Orleans process is still used to make vinegar, but other methods have been developed over the years to improve and speed up acetification even more. This is the case with the submerged fermentation process. Air is constantly pumped through, and the resulting millions of air bubbles provide the bacteria in the alcohol solution with oxygen for their rapid development. Thus more vinegar is produced in less time.
Vinegar has a long history. It is mentioned in the Bible in both the Hebrew and the Greek Scriptures. (Numbers 6:3; John 19:29, 30) Its medicinal value has been recognized for centuries. Hippocrates gave it to his patients. It has been inhaled as a stimulant and restorative, like smelling salts. Diluted in water, it has been used as a mild antiseptic. In the home, vinegar is used in water solutions to wash salad ingredients and as a general household cleaner.
But vinegar is used mainly for culinary purposes. Since it prevents microorganisms from developing, it is used for pickling meat, fish, fruit, and many vegetables, such as onions, gherkins, and cauliflower. And vinegar enhances the flavor of salads, sauces, stews, and other dishes.
So the next time you sit down to a meal, remember that its flavor may have been improved by that tangy acid, vinegar.