We received a complaint from a customer saying there is a chemical taste in our red wine. We tested it and all parameters were normal, and it was tasted by our winemaker, who responded that there is nothing wrong and that it’s still fruity. What could have caused the chemical taste?
There are several possibilities. One is Brettanomyces. “Brett” is a spoilage yeast, often associated with dirty barrels. It can give off a variety of off-flavours, variously described as metallic, manure-like (euphemistically referred to as barnyard) and Band-Aid. As a producer, you’ve done the lab work, so I suspect this is not the strongest possibility. That said, I notice from your e-mail signature that you’re writing from a large brand-development company in South Africa. It’s been widely observed that many South African reds have a synthetic overtone. It’s by no means necessarily a bad thing, but I can’t deny its existence. To me it comes across as smoky or rubbery, sometimes Band-Aid-like, though others might legitimately describe the flavour as metallic. I suspect that if your customer is South African and accustomed to drinking local wines, this – again – is probably not the issue.
The funny thing about wine is that we always tend to blame the bottle rather than ourselves or the food we’re eating when there’s a problem. Most people fail to appreciate that food strongly affects the flavour of wine, often, I must say, for the worse. Such items as eggs, artichokes and umami-rich soy sauce or tomatoes can cause a wine to taste metallic.
Health issues are another possibility. A metallic taste in the mouth is a common medical disorder. It’s got a name: dysgeusia. Often it’s linked to medications, such as some used to treat cancer, blood pressure, diabetes and heartburn. Antibiotics can cause it, too. These affect the flavour of food, of course, but often to a lesser degree, I think. Fine wine is a fragile pleasure, and it’s easier to find stray metal in a wine glass than in a bowl of stew.