Sulfur has been used in wine making since Roman times. Yet, today its role in wine growing and making is often misunderstood. Small amounts of sulfur are, in fact, essential for vine nutrition and for the stability of finished wines.
In the vineyard, sulfur is used to control molds and fungi, such as powdery mildew. For this purpose sulfur compounds sprayed on the vines periodically. As a vine nutrient, soils are rarely sulfur deficient so it is not routinely added as a nutrient.
In the winery, sulfur is used for its antimicrobial properties and as wine preservative that naturally protects the wine from oxidation. The small amounts of sulfur compounds present in finished wines have no effect on the wine drinking experience except in the rare case of the drinker being truly allergic. In point of fact, modern winemakers use far less sulfur than was common even a couple of decades ago.