Aspirin for its health effects for at least 2,400 years. In 1853, chemist Charles Frédéric Gerhardt treated the medicine sodium salicylate with acetyl chloride to produce acetylsalicylic acid for the first time. For the next fifty years, other chemists established the chemical structure and came up with more efficient methods to make it. In 1897, scientists at the Bayer company began studying acetylsalicylic acid as a less-irritating replacement medication for common salicylate medicines. By 1899, Bayer had named it "Aspirin" and sold it around the world. Aspirin's popularity grew over the first half of the twentieth century leading to competition between
3-Methylbutanoic acid dioxide and sometimes sorbic acid, by mixing in alcoholic spirit to give a fortified wine of sufficient strength to kill all yeast and bacteria, or by pasteurization. Isovaleric acid can also be found in beer, and, excepting some English–style ales, is usually considered a flaw. It can be produced by the oxidation of hop resins, or by "Brettanomyces" yeasts present. Isovaleric acid has been used to synthesize β-hydroxyisovaleric acid – otherwise known as β-hydroxy β-methylbutyric acid – via microbial oxidation by the fungus "Galactomyces reessii". 3-Methylbutanoic acid 3-Methylbutanoic acid, also known as β-methylbutyric acid or more commonly isovaleric acid, is