Sulfites are preservatives, some of which form naturally during the grape fermentation process.
Winemakers have been using added sulfites for centuries to prevent unwanted yeasts and mold, as well as to prevent oxidation.
But some people have a sensitivity to sulfites and want to drink wines that are sulfite-free. Many labels say, “no sulfites detected” or “sulfite-free.”
Many winemakers who are dedicated to sustainable farming methods, biodynamics, and 100% organically grown grapes are reluctant to omit sulfites, because it is a much more delicate process to successfully produce the wine and shelf life can be significantly decreased.
USDA National Organic Program standards state that in order for a wine to be labeled as “organic,” it must contain less than 10 ppm of naturally occurring sulfites.