White wine as the heat accelerates its degradation. There are many other acids in small quantities: citric acid, ascorbic acid, α-ketoglutaric, fumaric acid, galacturonic acid, coumaric acid, etc. Their variable quantity varies the pH of the wort. The must of white wine is generally more acidic than red grape must simply because the grape maturity is less advanced. Vitamin C (or ascorbic acid) is present in the grape and the must up to 50 milligrams per litre. It is a protection in the wort against the oxidation phenomenon. In the presence of oxygen it produces hydrogen peroxide; by this reaction it deprives
Chemistry of ascorbic acid from animal adrenal glands. In 1932 Charles Glen King confirmed that it was indeed the antiscorbutic factor. In 1933, sugar chemist Walter Norman Haworth, working with samples of "hexuronic acid" that Szent-Györgyi had isolated from paprika and sent him in the previous year, deduced the correct structure and optical-isomeric nature of the compound, and in 1934 reported its first synthesis. In reference to the compound's antiscorbutic properties, Haworth and Szent-Györgyi proposed to rename it "a-scorbic acid" for the compound, and later specifically -ascorbic acid. Because of their work, in 1937 the Nobel Prizes for chemistry and medicine were awarded to