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The question
Help me settle a bet. I recently opened a wine that smelled literally of sewage. Was it corked?
The answer
Was that bottle consumed while viewing the DVD release of Jobs starring Ashton Kutcher? In which case the stench might not have come from the wine. But seriously, I'm pretty certain it was not corked.
Eau de sewage is the hallmark of hydrogen sulphide. The pesky compound is the bane of winemakers everywhere, a product of natural microbial activity in the fermenting tank. H2S can be blamed on a number of factors, including poor winery hygiene and insufficient nitrogen in the vineyard (yeast in the fermenting tank need sufficient nitrogen for energy or they start to acquire the microbe's equivalent of gastrointestinal distress). It also tends to be more prevalent in wines sealed with screw caps, which tend to trap the volatile gas more effectively than porous cork.
Often winemakers will combat the problem by aerating the wine gently or by adding in tiny amounts of copper sulfate. Something as benign as pumping the liquid through copper tubing can neutralize the substance. At home, you can quickly and safely get rid of the stench, should you want to bother, by placing a clean copper penny in your glass and waiting for a couple of minutes. Copper binds with the H2S to form copper sulfide. If you can't find a (discontinued) Canadian penny, alternatively decant the wine to agitate. This will encourage the H2S gas to escape. You can swirl the glass aggressively, too, assuming you've got one of those big fancy glasses to guard against spills.
A "corked" wine, on the other hand, has been contaminated with a substance called TCA, which often forms in raw cork bark when a certain fungus combines with chlorine either from rainwater or from the cork cleaning or bleaching process. TCA smells more like mouldy cardboard or dirty sneakers. Once your wine is infected with TCA, nothing will remove it; your wine's dead.
Because you described the wine as sewage-like, I'm guessing your bottle was contaminated more specifically with mercaptans, a particularly stinky group of compounds that form when H2S is left unchecked. Literally these are the same chemicals that take up residence in sewers. The more common H2S smell in wine resembles rotten eggs – or, in cinematic terms, Johnny Depp in The Lone Ranger.
The Flavour Principle, by Lucy Waverman and Beppi Crosariol, was named best Canadian Food & Drinks Book in the 2014 Gourmand World Cookbook Awards. Published by HarperCollins.
E-mail your wine and spirits questions to Beppi Crosariol. Look for answers to select questions to appear in the Wine & Spirits newsletter and on The Globe and Mail website.