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Explainer Know How

How Do You Know if a Wine Has Gone Bad?

The reasons why a wine can go from amazing to blah, seemingly overnight

Jeff Siegel By April 20, 2022
wine bottle swinging on the meter towards bad
Illustration by Ananda Walden

The woman reached under the sink and took out a bottle of white Zinfandel. “I’ve been saving this for four or five years for a special occasion,” she said, and proudly handed it to me. “Has it aged enough now?”

We were at her house for a wine tasting; a dozen or so people gathered for a Wine 101 class. And she was more than excited to show off her aged wine — because all wine should be aged, shouldn’t it?

So imagine her shock when the wine, which should have been light pink, had turned rusty, almost like pipe water. And it smelled like rubbing alcohol instead of sweet strawberries. That wasn’t better; that was much, much worse.

What happened?

Yes, this was inexpensive white Zinfandel and not a $100 red Bordeaux. But the principle is the same. Age, despite the assumption of many wine drinkers, is not necessarily a wine’s friend. Neither is heat or too much light. Says Sonoma winemaker Ryan Prichard, “Wine is essentially a point in time between fresh grapes and vinegar. And our job in the wine realm is to make that time last as long as possible.”

Much can go wrong between the time the bottle leaves the winery and when it ends up on the dining room table. It can turn to vinegar, change colors, or morph into an almost brandy-like liquid. And those are just the most obvious changes.

The good news is that 21st-century technology in winemaking, transportation, and storage, has reduced the chances of that happening. The bad news is that it’s still possible, and a wine’s journey from bottling to consumption is “one of the biggest and least recognized problems in wine,” says Dallas sommelier Jeffrey Gregory.

The best way to prevent those defects is to understand what causes them and, when possible, to take the necessary precautions. And, if something does happen, then to understand that Prichard’s point in time can be fleetingly short, even for the most expensive of wines.

Some basic truths

Wine, for all of its art and romance, is chemistry. Talk to winemakers, sommeliers, and wine judges, and the conversation can quickly turn to molecular bonding and sulfur reactions, featuring terms like esters and phenolic compounds — none of which sounds like something to pair with dinner. Yet despite all that science, there is still much that isn’t certain, save that all wine will eventually turn to vinegar. 

Generally, wine has two opportunities to go bad. The first is at the winery.

Many things can happen; among the most common are TCA, or cork taint; Brett; and volatile acidity, or VA. The first — technically 2,4,6-trichloroanisole — is a chemical that reacts with natural cork and can cause musty aromas and flavors in wines, including a wet dog smell. Brett, or Brettanomyces, is a naturally occurring yeast that can give the wine a barnyard aroma, while VA is a sign that the wine’s acidity has gone wrong, producing a nail polish remover-like aroma. None of these flaws are dangerous but just unpleasant.

The other opportunity comes during the often long and cumbersome process between winery and wine drinker. Or, the transportation and storage that happens in fits and starts and in all kinds of weather and climates. There’s the truck ride from the winery to the distributor; the ship from one country to another; the sitting in a retailer warehouse for weeks or even months. Much has been done over the past couple of decades to minimize the chances of spoilage, but it can still happen.

“That’s why, when you taste a wine at that small restaurant in Italy or at the winery in France, it will often taste differently when you drink it at home,” says Gregory. “That’s the missing piece of the puzzle. When you drink the wine where it was made, or almost where it was made, then there is less chance that something can go wrong.”

Which brings the discussion to heat, light, and aging. The white Zinfandel mentioned above went off because it was stored in the kitchen, the warmest room in the house, and because it aged too long. While wines can age for decades, most wines will go off in just a couple of years, particularly the simple ones. Heat accelerates the aging process, so that wine stored past 80 degrees Fahrenheit, says Gregory, may not even last that long. Throw light into the equation, which can make a wine hotter, and that $50 bottle bought to last a decade might only last a couple of years.

“I think there’s a higher risk for wines made pre-1980s,” says Scott Torrence, the owner of Chapter 4, a company that buys wine on the secondary market, which needs to pay particular attention to spoilage. “We know more about what can go wrong and how to prevent it, and we take better care of wine now, what with refrigeration and temperature control.”

There’s the truck ride from the winery to the distributor; the ship from one country to another; the sitting in a retailer warehouse for weeks or even months. Much has been done over the past couple of decades to minimize the chances of spoilage, but it can still happen.

Understanding the lingo

At its most basic, the effects of heat, light, and age can be grouped into three areas: oxidation, maderization, and “dumbing,” a term that accounts for wines that change color and taste as they age, though the changes may not be permanent.

Wine oxidation is similar to what happens to an apple that’s exposed to oxygen — it turns brown and may acquire an off-taste. Wine is especially susceptible to oxidation throughout the transportation process, says Torrence, because of heat and light. If the closure comes loose, whether during shipping or storage, it can oxidize, even at home. An oxidized wine will brown and pick up an almost brandy-ish taste. Once oxidized, little can be done to restore it to its original condition.

Maderization, says Gregory, is a “cooked” wine; that is, the wine has become so hot that it tastes like it was cooked. The term refers to a fortified wine called Madeira, which uses high heat in the winemaking process to give it a distinctive, nutty flavor. In that case, the heat is controlled; during maderization, the wine roasts on its own, and the results can be disastrous. 

Finally, dumbing. The flavor of some wines can become silent for a while; the best analogy may be trees shedding their leaves and going dormant in the winter, only to sprout new growth in the spring. Some wines, like Rieslings and white Burgundy, are well known for having dumb phases.

How and why this happens remains a mystery, says Torrence, though much research is underway. One culprit may be sulfur and how it reacts with wine as the wine ages, he says. The difference between dumbing and other problems is that a dumb wine can revive, given enough time.

Not to worry if all this sounds complicated, says Jay Bileti, a certified wine judge and former American Wine Society board member. It is for almost everyone.

“The problem, especially if you don’t know the wine that well, is that these changes can be difficult to taste,” he says. “There are going to be different effects for different wines.”

How do you know if there are problems?

First, look for changes to the bottle and closure to see if something could have happened. 

Has liquid seeped out around the closure and the foil that surrounds it? Has the cork been pushed up so that it’s not flush with the top of the bottle? Does the label seem sticky or wet? Does the wine level in the bottle seem lower than usual? 

Each is a sign that the wine could have oxidized or undergone maderization.

The next step is to taste carefully and hope for the best. Inexpensive white Zinfandel isn’t the only wine that can go off.

Finally, don’t be afraid to throw the wine away if it has cooked, unpleasant, or other off-flavors. What’s the point of drinking wine that has gone off? Off is off, whether wine or ketchup.

And if it seems like the flavor has disappeared, and you have more than one bottle, put it back into the darkness. The flavors might come back — and that’s a treat to behold, a victory over bad wine.