Facts and Concerns About Sulfites in Wine

Kate Miller-Wilson

If you're concerned about sulfites in wine, you aren't alone. While certain sensitive groups and those with sulfite allergies do need to avoid wines with sulfites, these substances are not harmful to most people.

What Are Sulfites?

The word "sulfites" refers to a variety of chemical combinations featuring the sulfite ion (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.

Sulfites occur in wine as a natural part of the fermentation process, and can also be added as a preservative. You can expect to find higher concentrations of sulfites in white wine than in red wine, and desert wines often have the highest sulfite levels.

Natural Sulfites

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 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.

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. In addition to preserving wine, sulfites can be used to control the timing of fermentation.

Sulfite Sensitivities

There's a reason sulfites have a reputation as being harmful, since they are one of the most common food sensitivities. According to the Food and Drug Administration, about one percent 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.

Labeling for Sulfites

In 1987, the United States passed a law requiring winemakers to label products containing a significant amount of additional sulfites. A similar law was put into effect in 2005 to regulate the labeling of European wines.

Wine labeling is generally very clear, 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 food products. For instance, dried fruit often contains up to 1000 parts per million (ppm) 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 European Union, the SO2 level guidelines are as follows:

  • Sweet desert wines can contain no more than 400 ppm.
  • Red wines can contain no more than 160 ppm.
  • White wines can contain no more than 210 ppm.

As a rule, sulfite levels are higher in white wines and sweet wines. If you have a mild sensitivity, you may want to avoid these beverages.

Wine Without Sulfites

In recent years, winemakers have begun to market organic wines and other wines without 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.

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 SO2.

Facts and Concerns About Sulfites in Wine