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What are sulfites? Where do sulfites come from? What do sulfites in wine do? Are they bad for you? Are they an allergen? Continue reading to learn the truth about sulfites in wine!

Sulfites in Wine - Wine Label - Contains Sulfites

What are Sulfites, and Where Do They Come From?

From a chemistry point of view, a sulfite is simply a chemical compound containing the sulfite ion (SO32-). In the world of food and beverage, sulfites are a preservative. The sulfite commonly found in wine is sulfur dioxide (SO2), and you may be surprised to know that sulfites in wine are actually naturally occurring. The fermentation process of winemaking naturally creates sulfur dioxide as a by-product. Consequently, all wine contains sulfites.

While wine receives a lot of attention due to its containing sulfites, the truth is that many foods contain sulfites. In fact, anything foods that are processed at all are likely to contain at least some sulfites. Baked goods, soup mixes, jam, canned vegetables, chips, tea, frozen potatoes, and more often contain sulfites.

Sulfites in Wine - The Winemaking Process - Barrels of Wine from Domaine Deveney Mars

What Do Sulfites in Wine Do?

Not only are sulfites naturally occurring in wine, they are actually pretty important. Sulfites help preserve wine against some yeast and bacteria. Without them, wine can quickly turn into vinegar.

Winemaking requires a lot of balancing acts, and the sulfite levels are another important element in all of this. In order for grape juice to turn into wine, Saccharomyces yeast must eat the sugar and turn it into alcohol. However, there is also bacteria that likes to feed on the same sugar. These bacteria can cause wine to smell like vinegar or acetone. The yeast naturally produces sulfites, and the sulfites fight the bacteria. Sometimes the winemaker must intervene by adding some sulfur dioxide to give the yeast a helping hand against the bacteria.

Sulfites in Wine - Labeling

The Truth About Sulfites on Wine Labels

If all wines contain sulfites, why do only some labels say they contain this chemical compound? “Contains Sulfites” might be a little bit deceiving. A more accurate descriptor would be “Contains at Least 10 mg/L of Sulfites”. While that option is wordier, it reflects the truth about sulfites in wine labels.

In the late 1980s, a spike in asthma cases led the Food and Drug Administration (FDA) to declare sulfites as an allergen. This led to the labeling requirement that wine labels must disclose if a level of 10 mg/L of sulfites or higher can be detected in the wine. To obtain the label of “sulfite-free” in the wine world, the level of sulfites must be lower and you have to apply for a special exemption.

Sulfites in Wine - Allergies

Sulfite Allergies

While sulfites have been identified as an allergen by the FDA, it’s important to note that most people are not actually allergic to them. The FDA estimates that only 1% of the population has a sulfite sensitivity.

When talking about headaches after drinking wine, many people attribute that “wine flu” symptom to sulfites. However, the 2008 study “Alcohol and migraine: trigger factor, consumption, mechanisms. A review” from The Journal of Headache and Pain found that even in people diagnosed with asthmatic sulfite allergies sulfites have not been linked to headaches. While it’s true that sulfites are present in wine and people can get headaches from drinking a little bit too much wine, those same people often eat foods that contain way more sulfites than the wine they drink and do not complain of headaches from those. Furthermore, studies have found that people complain of headaches just as much after drinking “sulfite-free” wines. The assumption that sulfites cause headaches appears to be an example of correlation and not causation.

Sulfites in Wine - Headaches

Wine Headaches

If the truth about sulfites in wine is that they most likely aren’t causing headaches, then what is? While no single explanation exists, alcohol, histamines, and tannins have all been linked to headaches.

Alcohol has a dehydrating effect that, of course, can lead to headaches. So, make sure to drink some water in between glasses of wine.

Histamines can dilate blood vessels, which can then lead to headaches. Grape skins contain histamine. Since red wine uses the whole grape in the winemaking process while white wine is made without the grape skin, red wine tends to contain higher levels of histamines. Before you blame histamines for your post-wine headache, beware that other foods – such as aged cheese, eggplant, spinach, fish, sausage, and salami – contain more histamines than wine.

Tannins help give wine its flavor, texture, and mouthfeel. They also provide a sense of weight and structure and create the drying sensation in your mouth that you often get with red wine and some whites. Additionally, tannins cue your brain to release the neurotransmitter serotonin. At high levels, this can cause headaches in some people. Again, before you determine tannins to be the culprit, beware that tannins can also be found in a variety of food and beverages that you might also be consuming. Tea, dark chocolate, some berries, and nuts all contain tannins.

So, while many theories exist as to why some experience headaches after drinking wine, there does not appear to be one theory that wins over the rest.

French Onion Soup - Hangover Remedy

French Hangover Cures

Since we aren’t going to skip the wine anytime soon, we’ll stick to the usual remedy in those cases that we get a wine headache: plenty of water and some over-the-counter pain relievers (following the instructions on the label, of course). In the case that we need a little something extra for a more serious case of the wine flu, cassoulet is a go-to French hangover “cure”. This French casserole or stew is just the hearty meal you need to feel revitalized. Another popular option is traditional French onion soup with its warm, cheesy goodness.

Leave a comment below with your after-drinking routines!

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Julia is happy to help with any custom orders. Please reach out to her via email at julia@sommailier.com.

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