Wine and Sulfites

Wine and Sulfites

Sulfites, usually in the form of sulfur dioxide (SO2), are found in all wine since they are present in grape juice. Wine made without added sulfur will contain up to 10 parts per million (PPM). Wine with sulfur levels higher than 10 milligrams per liter must be labelled “Contains Sulfites.” There has been no controlled study that links these low levels of sulfites to headaches or any other deleterious health issue despite widespread belief to the contrary.

Sulfites are added to almost all wine not expressly labelled “organic.” This addition may be in the form of sulfur salts, solution, or gas. Most often it’s added to the wine during the crush and again after fermentation.

The purpose of adding sulfites is to inhibit unwanted microbial activity in the wine. Sulfur is the preservative of choice as it bonds with the color pigments and leaves no apparent smell or taste in the wine. But an excess of sulfites results in “free sulfur” that is readily detectable in the aroma and flavor of the wine.

Sulfur dioxide is very volatile. When used correctly you should not notice its presence at all. But when you open a fresh bottle of wine and fill your glass any free sulfur may be detectable in the aroma. This should dissipate within a matter of a minute or two. If it continues to be noticeable the wine was oversulfured.

Wineries are trying to reduce their levels of added sulfur by keeping their stored wine as close to 52° as possible. Microbial activity in the wine increases with temperature. Also, higher alcohol levels discourage spoilage bacteria. It’s a common saying among wine lovers that today’s 14% is yesterday’s 13%. Part of the rise in alcohol levels we are seeing stems from the desire to reduce added sulfites but also from the desire for richer, bolder wine styles.