Alcohol has been around with human beings for as long as 13,000 years, with beer and wine residues being found in archaeological sites on multiple continents. And it’s not surprising because the moment you take any source of sugars and water, and just give it time, ethanol (also known as ethyl alcohol) will be produced with near certainty. The alchemist in this process is a tiny, single-celled microbe called Saccharomyces cerevisiae that breaks starches and sugars into ethanol and carbon dioxide.
In the wild, yeast is everywhere. It’s on the skins of grains, fruits and vegetables. It lies, waiting for fruits to ripen, soften and release their sugars for fermentation to happen. That blackened banana that went to mush on your kitchen counter—it probably has anywhere from 0.5-1% alcohol by volume.
Of course, wild fermentation is uncontrolled and unpredictable because the yeast has to compete with several other microbes—both good and bad bacteria, and pathogenic fungi (the hairy ones). So when human beings figured out that grape juice left to itself for a while turned into a pleasantly heady experience that they rather enjoyed, they started tinkering with the conditions. And thus was born the great culture and tradition of brewing.
Semantically speaking, fruits are fermented into wine and grains into beer, although this distinction can vary depending on which part of the world one is in. Hard liquor like whisky, vodka, gin and rum is produced by the addition of another step after fermentation to increase the concentration of alcohol—distillation. Despite the relatively booze-unfriendly culture in our part of the world, alcoholic drinks have been brewed in India for millennia. For example, feni is made by fermenting the cashew apple and then distilling it to produce a strong 40-45% alcohol-by-volume liquor. Toddy, a mildly alcoholic drink made from the fermented sap of palm trees, yields the more potent arrack when distilled.
Here is what happens when you drink something with alcohol. Ethanol by itself tastes sweet because it binds with the same receptors as sugars, but it also causes a burning sensation. Remember what happens when you eat chillies? The capsaicin molecule binds with a receptor that detects heat and fools your brain into thinking your mouth is on fire. Alcohol binds with the same receptor—thus the burning sensation in your mouth and throat, particularly when you drink hard liquor.
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But it also does something more interesting. It makes the receptor more sensitive and causes it to trigger the brain at a temperature that is slightly lower than your body’s normal temperature of 37 degrees Celsius. This has the effect of your brain starting to literally feel the heat of your own body! It’s not the alcohol, it’s your own body heat. And because ethanol ends up blocking these receptors, actually spicy food will taste relatively bland, which is why bar snacks tend to be quite intense to compensate. The sweetness of alcohol also pairs well with sour and bitter flavours, which is why gin and tonic works. You would never be able to tolerate those bitter herbs otherwise.
Another thing ethanol does is mess with the production of a hormone called vasopressin, which is responsible for helping your body retain water by controlling the kidney’s functioning. So when vasopressin is not produced, your kidneys simply let water go, which is why most bars need extra washrooms. This is also one of the reasons you get a hangover; it’s mostly dehydration.
If you have had a couple of glasses of wine, there’s a good chance that some of the ethanol has reached your brain—and because it’s a super-tiny molecule that loves reacting with fats, it gets through the blood-brain barrier with great ease and manages to mess with the way nerves communicate with one another. When that happens, your hand-eye coordination suffers, a condition we colloquially term “tipsy”. It also affects the functioning of the part of the brain that deals with self-control and inhibition, a phenomenon we are familiar with from the behaviour of middle-aged uncles at wedding parties.
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Alcoholic drinks can also play a stellar role in your kitchen. Beer, which tends to contain anywhere from 3-10% alcohol by volume, is simply not boozy enough for this purpose though. You can still use beer in your cooking as a souring agent because it is acidic. The fizziness is also useful in making the crispest possible pakodas. Just use beer instead of water when making the batter. You can also use soda water if you do not want to use beer.
Wine is a fantastic cooking medium. The grape juice flavours add complex sweet-sourness while the alcohol, a better solvent than water, helps extract more flavour molecules from spices. When used in gravies, most of the ethanol evaporates by the time the dish is cooked, so you do not have to worry about getting drunk from the aloo gobi gravy you just made. You can also use a tablespoon of hard liquor like brandy or rum, especially when deglazing the bottom of a pan, to liberate all those deliciously browned products of the Maillard reaction. As the legendary chef and culinary instructor Julia Child once said: “I enjoy cooking with wine. Sometimes I even put it in the food I am cooking.”
Krish Ashok is the author of Masala Lab: The Science Of Indian Cooking.