All You Need to Know about Sulfites in Wine: Debunking Myths

A lot of concern surrounds those little words “Contains Sulfites” printed on the bottom of a label. It’s even more confusing seeing that the just U.S. and Australia require bottles be labeled. So what should wine lovers think of it? What’s the deal with sulfites in wine and should we be worried about their effect? Today we get to the bottom of this debate as we hope to convince you sulfites in wine are not bad as you might think.

red and white wine in glasses


Why Are Sulfites in Wine?

The purpose of sulfites is very simple: They act as preservatives to wine. This beverage is volatile, meaning it spoils very easily. Did you ever open a wine that was bad by the next day? That happens when sulfites are cut out of the equation.

Wineries have been using sulfur for a long time; the preservative goes back to the Roman times. Back then, winemakers would burn sulfur candles in empty wine containers to keep the alcohol liquid from turning to vinegar. In more modern times, sulfur became once again connected to winemaking in the early 1900s. Instead of just cleaning wine barrels, winemakers realized they needed something stronger to stop bacteria and other yeasts from growing.

In addition to protecting wines from going bad, sulfites also help in the extraction of pigments in wine. In other words, they make red wines ‘redder,’ which is considered a desirable quality.



So Are Sulfites in Wine Harmful?

SO2 has acquired somewhat of a bad rap over the years. Only the wines with less sulfites than 10 parts per million (PPM) are exempted. But here’s the rub: The fermentation process usually produces more sulfites than that naturally, which means that even many ‘no added sulfite’ wines are required to display the “offending words” on their label.

Many believe this means sulfites in wine are harmful and should be avoided. In reality, that’s probably not true, at least not in the minuscule amounts found in modern wines. The typical beverage contains 20-200 PPM, which is insignificant compared with a handful of dried fruit (500-3,000 PPM).

  • Wines with more color (meaning red wines) require less sulfur than clear wines (white wines).
  • Wines with higher sugar content need more sulfur; the added SO2 prevents secondary fermentation of the remaining sugar.
  • Wines with higher acidity wines require less sulfur than lower acidity ones. It’s an exponential ratio, so wines with pH 3.6 and above need more sulfites.
  • Warmer wines release free sulfur compounds (the unpleasant sulfur smell); they can be easily fixed through decanting and chilling.

Natural Sulfites vs. Added Sulfites

Sulfur dioxide – also known as sulfites – comes in two types: either natural or added. Faithful to their name, natural sulfites are totally natural compounds resulting after fermentation. These are unescapable, which is why you cannot drink a completely sulfite-free wine.

Yes, you heard that right. Sulfite-free wines are a myth that we’re debunking right now, because it is literally impossible for a winemaker to prevent the natural sulfites from producing. Sulfites also act as a preservative, but the fermentation process cannot produce enough sulfites to protect the wine from going bad over time. For anyone who thought they could just drink a wine that’s been sitting around for more 50 years, sorry to burst your bubble.

Added sulfites, on the other hand, are required to preserve the wine’s freshness and protect it from unwanted bacteria, oxidation, and yeasts. Skip the added sulfites and that treasured 1961 Bordeaux would instantly turn into trash vinegar. Karen MacNeil, editor of the weekly wine report WineSpeed and author of The Wine Bible, knows what’s up.

“Sulfites are among the most helpful compounds around—and without them, some wines would taste like a microbial stew. Sulphur is a natural anti-microbial agent. It’s a terrific aid to winemakers—and ultimately wine drinkers, because it destroys bad microbes.” – Karen MacNeil

Sulfite Allergy – You Probably Don’t Have It

Sulfite allergy is another concern quoted by those seeking sulfite-free wines. Most of the time when someone blames wine headaches on sulfites, they might ignore the amount of wine they’re actually drinking. That is to say that overdoing the occasional wine glass is more likely the cause of your adverse reactions.

According to the FDA estimates, less than 1% of the U.S. population actually has a sulfite allergy, which means you have a miniscule chance of being allergic to wine. Also, those who do have a sulfite allergy are most likely asthmatic too. Symptoms of allergy to wine include hives and trouble breathing within 30 minutes of sulfite exposure.

You might still experience some red wine headaches eve if you’re not asthmatic and you’re not drinking too much. There is a chance the headaches can be caused by the histamines present in red wine. Are you predisposed to allergies like hay fever? Take a Claritin before hitting the bottle and don’t forget to drink plenty of water (allergenic or not).

French Fries Have More Sulfites than Wine



No-one wants to find out more reasons to not love French fries, but they do contain around 1900 PPM. But don’t give it too much thought. Everything you eat contains sulfites, from pickles to painkillers to pizza crust. That delicious order of shrimp? It has more sulfites than a whole bottle of Sangiovese.

There’s a reason why sulfites became so controversial. Back in the 1980s, the large amount of sulfur used in preservatives caused a rise in sulfur allergic reactions. Imagine if everything you bought suddenly had a ton of peanuts in it and there was no warning. A bunch of kids with nut allergies would end up in the hospital, or worse, so the outrage would be reasonable.

We want companies to disclose when peanuts are in their products, and the same goes for sulfites. However, that doesn’t mean you – a non-sulfites-allergic-person – should spend the rest of your life terrified of every bottle of wine.

Now What?

There’s nothing stopping you from living your life with the wine flowing freely. If you’re worried about added chemicals in wine, know that sulfur is just one. There are dozens of added yeasts, gelatin, sugars, and a lot worse in that wine that no one tells you about. For ease of mind, ask for low-intervention wines at your local wine store. They contain as few chemicals as possible and are very often “sans soufre” (without sulfur).

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William E. Eubanks

I'm one of the main writers on the site; mostly dealing with environmental news and ways to live green. My goal is to educate others about this great planet, and the ways we can help to protect it.

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