Everything you always wanted to know about sulfites in wine (but were too afraid to ask)

Pinnacle Ridge owner and winemaker Brad Knapp recently shared his knowledge of sulfites with the readers of the winery's monthly e-newsletter. Here is the article that appeared in the January e-newsletter.

We have all observed the term “contains sulfites” on virtually every bottle of wine we’ve consumed, yet most of us don’t understand what it means. What are sulfites? Why are they in wine? Is it natural or added? What happens if there are no sulfites?

In the United States, it is a requirement of the Food and Drug Administration (FDA) for a wine label to display the term “contains sulfites” if the wine contains ten parts per million or more of sulfites. Ten parts per million is the same as 0.001% by weight. In other words, sulfites must make up 0.001% (one one-thousandth of one percent) of the weight of the wine before the term is required on the label. 

Sulfites (or SO2) are a natural product of yeast fermentation and are also added to wine as a preservative.  Sometimes the natural yeast fermentation will produce over ten parts per million of sulfites and sometimes not. Over 99% of the wine made in the world contains over 10 ppm sulfites. Wine with  less than 10 ppm sulfites typically will age very badly and white wines will brown and lose their fruit and freshness. Red wine color will also turn brown and the flavors will get very muddy and tired without sulfites to help inhibit oxidation.

So why did the FDA institute the labeling requirement in 1987?

It turns out that a very small percentage of the population (under 1%) shows allergic reactions to sulfites. If you think you might have a sulfite allergy, just take a bite of a dried apricot and you’ll find out soon enough. A two ounce serving of dried apricot typically contains around ten times the sulfites in a glass of wine.

Sulfites are used in many foods as a preservative, yet these foods do not require the label. Salad bars are another place that sulfites are used to stop browning of lettuce and vegetables. Many folks think that wines produced in Europe are made without the use of sulfites. This is completely untrue and this myth probably was started because European wines (those sold in Europe) were not required to display the “contains sulfite” term until 2005 (nearly 20 years after the requirement in the US).

If you have a problem with sulfites, try wines labeled “organic.” Organic wines cannot have added sulfites. Wines labeled “made from organically grown grapes” may or may not have sulfites. Look for the “contains sulfites” term on the  label. 

People may think they have sensitivity to sulfite when, in fact, they have issues with tannins in wine. Tannins are compounds that are in the skins and seeds of grapes. Tannins are present in much higher levels in red wines compared to white wines. If you find you have issues with red wines and not with whites then the problem is most likely tannins. If you get headaches, the issue is probably tannins not sulfites. There is no known medical evidence showing that the consumption of the tiny amount of sulfites in wine results in headaches.