Where does vinegar come from and how is it made? Yes, we can deduce that apple cider vinegar and rice wine vinegar come from apples and rice, respectively, but how do they become vinegar? And the origins of less obvious vinegars are even more murky. From where does plain white vinegar come? How about balsamic, sherry or malt vinegars? The list goes on and on, and it has haunted me the past few nights. Let’s get to the bottom of this.
This strong, nose-wrinkling liquid owes its sourness to acetic acid. Surprisingly, acetic acid only accounts for about 5% by volume of most vinegars. The rest is water, and some vinegars may have additional seasonings like spices or extra sugar. Acetic acid isn't actually extracted from fruits and grains like apples or rice, though. Rather, a fermentation process synthesizes it.
Let’s use the examples of apple cider vinegar and rice wine vinegar. Apples and rice are fermented in a mixture of water, yeast, and sugar to develop the alcohol ethanol. Then, the precursors to “hard apple cider” and “rice wine” are further fermented with added Mycoderma aceti, an acetic acid bacteria culture aptly named Mother of Vinegar. In this step, the bacteria convert the ethanol into acetic acid. In other words, the “hard apple cider” turns into apple cider vinegar and the “rice wine” turns into rice wine vinegar.
The key to sustaining yeast and bacterial fermentation is a high amount of sugar. That’s why sugar-rich grains and fruits are used for vinegars and not broccoli or zucchini. Here’s where some of the less obvious vinegars are derived from.
Sugar cane or corn makes white table vinegar
Malting barley ale makes malt vinegar
Sherry wine (grapes) makes sherry vinegar
White Trebbiano grapes (an Italian wine grape) make balsamic vinegar
Coconut sap or juice makes coconut vinegar, common in Southeast Asian cuisine
A combination of rice, wheat, millet make Chinese black vinegar
How does pickling preserve food?
Vinegar’s acidity makes it perfect for pickling because it creates an environment too harsh for most spoiling bacteria to grow. But why? Let’s take a closer look into what maintains a functioning bacteria - and what disrupts it.
Acids dissolved in water contain tiny positively charged hydrogen ions, or protons. While these wee little protons may seem negligible in effect, they can devastate the cellular machinery of bacteria. I imagine a proton to be like a little pea under the mattress in the story, The Princess and the Pea. It could cause a small chemical change, or “bump in the mattress,” that eventually kills the bacteria.
For example, acids disrupt the very basis of life, DNA, by disrupting the hydrogen bonds that act as the connecting “rungs” of DNA. Excess protons from acids can disrupt delicately controlled cellular proton concentrations, halting energy production. The most sensitive cellular machinery are proteins, and they are often most hard hit by small chemical changes because of their complex and specialized structures and functionalities. Unless the bacteria species has evolved to survive and thrive in a strongly acidic environment (like our gut flora), vinegar absolutely wrecks fundamental cellular machinery.
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