Sulfurization of the pulp, must and wine.
In the description of cleaning and maintenance of wooden dishes, it has already been mentioned, that sulfur is an effective germicide with a centuries-old tradition. Sulfur is used not only for the preservation of "wet" and "dry" barrels, but it is also added directly to the must, pulp and wine in the form of potassium metabisulphite tablets or in large wineries – directly as sulfur dioxide gas SO2.
Sulfur contained in SO2 (Sulphur dioxide) or in the salts of sulfuric acid (sulfites), as "harmful to health", has been fought for a long time by supporters of natural cultivation and wine production. Already in the 15th century sulfuration of wine was forbidden in Cologne, because it "harms the nature of man and can make the drinker sick". We do not know, in what amounts did winemakers add sulfur to their wine in their time; today there are strict limits to the use of sulfur; to the critically oriented winemakers, they seem too high anyway. Sulfated wines have a high alcohol content and are sweet. It used to be impossible to produce other wine, as soon as fermented to the end, so dry and with no added sugar. However, the more residual sweetness in the wine, the more it must be sulfurized. The juice and the pulp are already sulfated, even if they have not yet been corrected. This inhibits the growth of acetic acid bacteria, wild yeast and mold.
Sulfurization of young wine (so after the first dressing) stops the growth of acid-decomposing bacteria and thus prevents the loss of acidity too early, which would lead to this, that the wine would become bland and sterile and unstable already at this stage. Sulfur also prevents certain wine diseases, like vinegar, pieces of lactic acid, mock the mouse, or "mouse", mucilage.
Dispute, whether sulfur should be used in wine production, or not, it is pointless, because so far no substitute has been found, which would be just as effective, and less aggressive. Both winemakers using conventional methods, and this one, who uses alternative methods, cannot do without sulfur. All proposed replacement measures require this investment, that even the larger wineries cannot afford to use them, much less the winemaker – amateur.
Only, What can we do, this is to limit the use of sulfur to the lowest possible level. I personally divided the amounts given in the specialist literature, nothing less than, in half and using them for years, I have never regretted it. Of course a statement: „Na 100 gallons of juice or pulp to take instead 10 g only 5 g of potassium metabisulphite "cannot be so easily generalized. Here is an example from my practice: I made Sylvaner white dry wine with a weight of 80 ° Ochsle and total acid content 9,5 g, so no residual sugar, and I didn't add any sulfur to it. The condition was healthy and clean fruit, pressing the juice immediately, degumming after one day, efficient fermentation with the addition of dry wine yeast, the first dressing and automatic clarification carried out in a short time in the "half" barrel (600 liters).
On the other hand, I sulphated the riesling from very ripe fruit, adding 5 g of potassium metabisulfite na 100 liters, and I treated it exactly the same, like with wine, which I described in the example above. I got an equally good dry wine.
You can do that, but such wines cannot be kept for too long, they should be drunk while they are young, after a year or two at the latest.
First you have to wait for the results of the wine treatments, and then use a single chemical – carefully and in the right proportions.
• Juice or pulp from not entirely healthy fruit should be sulfurized, adding 5 g of potassium metabisulfite na 100 l, and only in exceptional cases 10 g.
• Potassium metabisulfite is most effective in tablet form, it's better not to buy it in powder form. Keep the tablets tightly closed in a dry place. Tablets in open packages lose their bactericidal properties after just a few days. The tablets are crushed, they are dissolved in the juice and added to the setting.