Understanding Sulfites in Wine

Karen Frazier
Woman in kitchen with food and wine

Wines naturally contain a small amount of sulfites. However, sulfites are also added to wine during the winemaking process as a preservative to help maintain the wine's flavor. For some people, the addition of sulfites will never be an issue. For others, wines containing added sulfites can be problematic.

What Are Sulfites in Wine?

The word sulfites refers to a variety of chemical combinations containing sulfer dioxide (SO2). In the past few decades, there has been significant consumer concern about sulfites, and winemakers are now required to clearly label bottles containing these substances.

Natural Sulfites in Wine

When you buy a bottle of organic wine, which legally cannot contain added sulfites, there may still be some SO2 present in the beverage. This is because sulfite ions bind to create various molecules during fermentation. These substances are yeast byproducts, and are produced as the yeast consumes the sugar in the grape juice. In fact, as winemakers have become more experienced and educated in this process, some companies have been able to reduce or eliminate the need for additional SO2 in wine. Wines relying only on natural sulfites as a preservative typically have a shorter shelf life.

Sulfites as a Wine Preservative

Sulfites are used as a preservative in a variety of applications, especially those involving dried fruit and potatoes. They help maintain the freshness, taste, and texture of these products, and they are used for the same purpose in winemaking. Sulfites extend the wine's shelf life and reduce the degradation of its flavors, especially in white or ligher wines. They may also be added to sweet wines to stop fermentation and maintain a higher sugar level. In wines containing added SO2, the chemical is incorporated at various steps in the winemaking process. Even in the best bottling circumstances, some bacteria may be present in the wine or bottle. Sulfites help to keep these bacteria from changing the flavor of the beverage.

Sulfite Allergies and Sensitivities

There's a reason sulfites have a reputation as being harmful, since they are a common food sensitivity. According to the Food and Drug Administration, about 1% of the United States population suffers from this problem. Adverse reactions can begin at any time in a person's life, and there is a wide range of symptoms. Some people experience mild reactions like sneezing or hives, while others have a life-threatening response and may experience difficulty breathing. Some research has also indicated that those with severe asthma or other breathing difficulties may also experience adverse reactions due to SO2. If you have one of these conditions, you should avoid wine with high sulfite levels.

Do Sulfites Cause Red Wine Headaches?

It's a common misconception that red wine headaches are caused by sulfites in the wine. In fact, wine headaches are most likely caused by tannins, sugars, or something called histamines, which is the body's response to a substance to which it is allergic. Research has shown that aged foods such as wine and cheese can cause the body to release histamines, which can result in a headache. Dehydration from consuming alcohol without water can also contribute to headaches and hangovers.

Labeling for Sulfites in Wine

In 1987, the United States passed a law requiring winemakers to label products containing a significant amount of additional sulfites (more than 10 parts per million). Australia must also label wines containing sulfites. A similar law was put into effect in 2005 to regulate the labeling of European wines.

Wine labeling is generally very clear stating "contains sulfites", but you may see sulfites listed by the following names:

  • Potassium bisulfite
  • Potassium metabisulfite
  • Sodium sulfite
  • Sulfur dioxide
  • Sodium bisulfite
  • Sodium metabisulfite

Levels of Sulfites in Wine

Generally, wines have much lower SO2 levels than other food and beverage products. For instance, on average wine contains anywhere from about 5 parts per million (ppm) to 200 ppm of sulfites (red wine averages around 50 ppm), while dried fruit often contains 1,000 ppm or more of SO2. The maximum SO2 levels for wine vary depending on the country of origin, but most regulations place strict limits on wine manufacturers.

  • In the United States, the maximum legal limit for sulfites in wine is 350 ppm.
  • In the European Union, wines cannot contain more than 210 ppm.
  • In Australia, dry wines can contain a maximum of 250 ppm and sweet wines can contain a maximum of 300 ppm.
  • In general, sulfite levels are higher in white wines and sweet wines. Dry reds tend to contain the lowest level of sulfites, while rosé falls somewhere in the middle.

Wine Without Sulfites

In recent years, winemakers have begun to market organic wines and other wines without added sulfites. Generally, these options are dry red wines, since the natural tannins can help preserve the beverage. Many SO2-free wines also require special storage conditions to maintain their freshness.

There are a few ways to find wine without any additional sulfites:

  • Look for bottles that are labeled "organic wine" not "wine made from organic grapes." This is an important distinction, since winemakers cannot use the "organic wine" label if they add sulfites.
  • Ask about these wines at your local wine store or wineries. Since the lack of sulfites can mean a reduced shelf life, you may have good luck finding sulfite-free wines from local vineyards.
  • Read wine labels carefully. The label must clearly state that the wine contains sulfites.

Minimizing Sulfites in Wine

It's common to find sulfites in wine because these substances are an important part of the production and preservation process; however, if you have a sulfite sensitivity, you can find a wine that does not contain high levels of SO2.

Understanding Sulfites in Wine