Sulfur (sulfites) is a powdered stone which, added in small doses to wine, stabilizes it and prevents fermentation from restarting. It has a sanitizing role. In other words, sulphites allow wines to keep their characteristics and clean the tanks in which the wine is aged.
Wines without any trace of sulfites do not really exist, because sulfites (derived from sulfur), are found naturally everywhere in our food and in nature, including in organic wine or in natural wine.
Some wines are "without added sulphites", that is to say that no sulphites are added in the vines, neither during vinification nor during bottling, it is only the sulphites present naturally on the skin of the grapes which will be residual in the wine once ready to be tasted. You should also know that there are 3 times less sulphites in organic and 10 times less in biodynamics than in conventional viticulture. This is why we find the mention ''contains sulfites'' even on wines '' without added sulfites! ”. Some winegrowers refuse the use of sulphur, out of philosophy and the desire to produce the most “natural” wines possible, that is to say close to the fruit and the terroir.
From a molecular point of view, wine is an unstable balance between fruit juice and vinegar. For the wine to keep its balance and to be “stable”, it is common to use sulphites which have the role of stabilizer. Hop! It's easy to abuse it to make your job easier. Finding the perfect balance with the sulphites already present and those to be slightly added (or not), requires rigor and above all work, time and passion on the part of organic and biodynamic winegrowers.