Guest Post: Gerard Paul writes about food & drink at ManyEats. He insists you put down the fruit leather and pick up your wine glass. Cheers!
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Go to a store and pick up a bottle of wine. It's likely that the words "Contains sulfites" will be printed somewhere on the label.
We've taken a strange path to where we are today. Everyone has an opinion on sulfites, but not everyone understands their essential role in the winemaking process – without sulfites, you might be drinking vinegar.
So what's the deal with sulfites, anyway?
What Are Sulfites?
The word "sulfites" (sometimes styled "sulphites") are sulfur-containing compounds – including sulfur dioxide – that act as preservatives and antimicrobials.
In winemaking, sulfites are used to maintain flavor, improve a wine's shelf life, preserve freshness, and protect a wine's color from oxidation. Sulfur dioxide is a natural byproduct that arises during fermentation, but winemakers often add more sulfites as a preservative to achieve the positive effects noted above.
Adding extra sulfites to a batch of wine can slow or stop the fermentation process and help the wine remain stable even after bottling.
Sulfites in White vs. Red Wines?
Let's get something out of the way: all wines will contain some amount of sulfites. That includes wines made with controlled low-sulfite processes.
White wine generally has more sulfites than red due to the differences in fermentation techniques. Being the sweeter of the two, white wine contains more sugar, which attracts bacteria.
Although yeast is the primary driver during wine's fermentation process, some bacteria are likely necessary for fermentation (but too much can lead to spoilage).
White-winemakers use added sulfites to stop the fermentation process before bacteria consume residual sugar. On the other hand, red wine is fermented with grape seeds, stems, and skin within. This introduces tannins into the wine, a natural antioxidant and preservative. Due to the tannins, red wines generally need fewer added sulfites for stabilization.
Natural Sulfites vs. Added Sulfites and Organic Wine
"Added" sulfites refer to any sulfites introduced to a batch of wine beyond what occurs naturally.
The content of naturally-occurring sulfites in wine usually range from 10-80ppm ("parts per million"), depending on the wine.
In the United States, wine without any sulfites added (and some other requirements [PDF]) can be labeled "organic wine" and include the USDA Organic Seal. There is a lesser certification of "made with organic grapes" as well – winemakers can't use the seal but can use the organic grapes label if they keep added sulfites below 100ppm.
Photo by Terry Vlisidis on Unsplash
Sulfites and Wine
Again, without sulfites, wine is more vulnerable to bacteria and spoilage. Especially in imported wines, winemakers rely on sulfites to keep the wine fresh during transport.
Sulfites are also one reason why wine tends to taste better with age. They help to preserve the wine's flavor and body, so they're an invaluable aspect of wine production and storage.
Is There Such a Thing as Sulfite-Free Wine?
There is no such thing as a 100% sulfite-free wine. Wine is produced through fermentation, and sulfites are a natural byproduct of the fermenting process – even if only in trace amounts.
Sometimes, wine is marketed as "sulfite-free." Sulfite-free wines have no added sulfites, but they will still contain trace amounts of natural sulfites. The closest wines to sulfite-free are organic wines without a "contains sulfite" label – they have a minimum concentration of sulfites (below 10ppm).
Taste of Lower Sulfite vs. Higher Sulfite Wines
Sulfites don't taste like much of anything in isolation, but their presence in wine can undoubtedly affect the flavor of the end product. At every stage of the winemaking process, the relative concentration of sulfites affects everything else in wine and changes how a wine tastes and feels.
And on the not-so-good side, since sulfites prevent bacteria growth, lower sulfite wines might have an unusual odor or spoil easier. Many casual wine drinkers report that some wines with no added sulfites lack the character and depth of traditionally-produced wines.
Also, low-sulfite wines are more prone to "mousiness." Mousiness is used to describe an aftertaste that some have likened to stinky cheese, dog breath, or mouse urine (I'd love to know who first made that observation).
Mousiness isn't necessarily harmful, but it can be extremely off-putting.
Are there Risks or Precautions for Low Sulfite Wines?
Wines with low sulfite content have a relatively short shelf life compared to wines with added sulfites. Once you uncork a low-sulfite wine, the presence of oxygen starts a series of reactions that cause it to deteriorate.
Wines with no added sulfites should be refrigerated after uncorking. Also, try not to keep them for too long – in general, discard your low-sulfite wines after three months.
(Actually, I'd suggest just finishing the bottle).
Legal Limits on Sulfite Concentration
In the United States, the total finished sulfite content of wine is limited to 350ppm or below.
Like I mentioned earlier, any wine with more than 10ppm sulfites must have the words "Contains sulfites" on the label to be sold in the United States. In Europe, sulfite content is limited to 160ppm for reds and 210ppm for whites.
Health Effects of Sulfites
Sulfites are harmless for most people, but there is a lot of misinformation about the nature of sulfites. Many people believe sulfites are harmful simply because they are a food additive.
However, years of research have concluded that sulfites on their own do not cause cancer, mutations, or fetal abnormalities.
Or, in almost all cases, headaches.
Are Sulfites Causing Your Headache?
No research suggests sulfites are the culprits behind the dreaded "red wine headache."
It's more likely your headache was caused by other compounds and byproducts in wine, such as alcohol, tannins, or histamines. While sulfite sensitivities do exist in some people, problems usually manifest as breathing difficulties rather than headaches.
Sulfite Allergies and Sensitivities
I've talked a lot about how sulfites have a worse reputation than they deserve. It's time for a significant caveat: sulfite allergies are possible, and they tend to occur hand-in-hand with asthma.
People with sulfite allergies generally exhibit the same symptoms as any other allergic reaction when exposed to sulfites, such as itchiness, swelling, and trouble breathing. Sufferers have the same risk of anaphylactic shock as with any other allergy. Therefore, asthmatics with a co-occurring sulfite allergy should take care to read product labels and possibly carry an EpiPen and rescue inhaler depending on the nature of their allergy.
Now, let's talk about sensitivities.
Unlike a full-blown sulfite allergy, sulfite sensitivity occurs when you lack sufficient quantities of the specific enzyme to process sulfites. Sensitivity causes various levels of inflammation rather than an allergic reaction. According to the FDA, just 1% of the U.S. population has a sulfite sensitivity – for all the sulfite talk, sensitivity is quite rare.
Foods with More Sulfites Than Wine
The weirdest thing about sulfite's undeserved reputation as an undesirable compound in wine is how its concentration compares to the level in other foods.
Wine has a lower concentration of sulfites than a whole lot of foods. For example, dried fruit can have as much as 2,000ppm of sulfites—nearly ten times the legal limit Europe allows in wine!
Here is a list of some foods that have higher sulfite levels than wine:
- Raisins
- Sun-dried tomatoes
- Fruit leather
- Canned soups
- Pickles
- Sauerkraut
- Molasses
- Deli meats and cheeses
- Pizza crust
- French fries
So, the next time your friend strikes up a conversation about sulfites in a bottle of wine, ask them to put down their french fries.
The Bottom of the Bottle: Sulfites in Wine
If you're entirely unconvinced – or among the low percentage of people with sulfite sensitivity – there are excellent organic or lower-sulfite wines for you to try nowadays. For the rest of us, drink your next bottle secure in the knowledge that the sulfites within are safe and unoffensive.
Still, there's no getting around it: sulfites are a controversial ingredient among wine enthusiasts and casual observers alike. They also have second-order effects on the taste and feel of a wine.
But they don't cause your wine headaches.