Your Tequila May Contain Methanol

Why Alcoholic Beverages May Be Contaminated

Tequila, and therefore margaritas, may contain toxic methanol. Bob Muschitz, Getty Images

Happy Cinco de Mayo! If your holiday celebration includes tequila, you may be interested to know the American Chemical Society (ACS) has found that some tequila contains methanol, 2-methyl-1-butanol and 2-phenylethanol.

In case you're wondering... no, these are not good and desirable chemicals to drink. The 'alcohol' in alcoholic beverages that you drink is ethyl alcohol or ethanol (grain alcohol). Methanol (wood alcohol) and other alcohols are the types that can make you go blind and otherwise cause permanent neurological damage, not to mention give you a nasty hangover. The ACS purposely timed the release of the results to coincide with Cinco de Mayo, to raise awareness of the quality control issue. Tequila made from 100% blue agave tended to have higher levels of the undesirable chemicals than other types of tequila (pure agave tequila is usually considered superior).

What does this mean? Is tequila somehow bad? No, actually tequila is one of the best-regulated alcoholic beverages in the world. The results not only point out a potential health hazard for this drink, but also indicate other beverages are probably adulterated with contaminants.

It's the nature of distillation. The process relies on boiling point differences between liquids, which means good control of temperature is key. Also, the first and last portion of alcohol that is distilled (the heads and the tails) contain other compounds besides ethanol. Not all of these molecules are bad -- they may impart flavor -- so a distiller may choose to retain a certain amount. Then, there is a risk of picking up contaminants during the aging process. It's tricky, which is why top shelf tequila is likely way better than home-grown moonshine, as far as your health goes.

Yet, it's possible to distill alcohol without the unwanted compounds. Why does the problem persist? It's partly a matter of economics, where a distillery determines what level of contamination is acceptable. Increasing purity decreases yield which decreases profit. It's partly a compromise between making a product with premium flavor, color, and scent while keeping toxins to a minimum. I mean, technically ethanol is a toxin, so the product won't be "good" for you no matter what.

So, while you're sipping that margarita today, take a moment to consider what's in your drink. It may be more than you bargained for!

The results of the ACS study were published in the Journal of Agricultural and Food Chemistry.

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