Sulfites and Wine
Sulfites occur naturally in all wine, it's a natural by-product of the fermentation process. The sulfite levels through the natural process are very low (0-15 ppm). However, often times, a preservative is added to the winemaking process to either arrest fermentation, prevent spoilage or oxidation, as well as other reasons. Some compounds used may be; sulphur dioxide (chemical oxide) resulting in SO2 or sulfites when added to water/wine, potassium bisulfite and sodium bisulfite. These compounds raise the levels of SO2 in a wine and introduce more chemicals to the wine you're going to drink.
Natural wine producers, and to a large extent, certified Organic wine makers, work with what comes and do not add any preservatives to the wine making process. Some might say, they welcome the diversity.
These farmers rely on the health of their vineyards, through conscious farming practices, they believe in the strength of their vineyards to grow great grapes. These vineyards are farmed in such a way that they produce grapes with diverse flora that will aid in the natural fermentation and, the hope is, will result in quality wines that age well in the cellar.
In other words, not adding sulfites isn't necessarily a bad business plan for these producers but can certainly create challenges. Just a brief note on some of those challenges: one such challenge is producing a wine different from what has been commercially accepted by the generally public and educating the consumer about natural wines -- as well as the varied taste profile. Making enough wine and, in some cases, a product that will last on the shelf are other challenges too.
According to the The Organic Wine Company the level of sulfites in wine is measured in “ppm”, or parts per million. In the United States, conventionally made wines are permitted to contain up to 350ppm of sulfites (included in this are the compounds mentioned above).
Organic wine-making typically limits the threshold level of sulfites to 100ppm, and levels are generally much lower (around 40ppm to 80 ppm)*. By current USDA Organic Standard, any wine, foreign or domestic, can contain only naturally occurring sulfites (less than 10ppm*) to be marketed and sold as an “organic wine” (Source/Website: The Organic Wine Company)