Brewing much studied, the preservative nature of the soft resins is not yet fully understood, though it has been observed that unless stored at a cool temperature, the preservative nature will decrease. Brewing is the sole major commercial use of hops. Yeast is the microorganism that is responsible for fermentation in beer. Yeast metabolises the sugars extracted from grains, which produces alcohol and carbon dioxide, and thereby turns wort into beer. In addition to fermenting the beer, yeast influences the character and flavour. The dominant types of yeast used to make beer are "Saccharomyces cerevisiae", known as ale yeast, and "Saccharomyces
Allyl alcohol be obtained by dehydrogenation of propanol. In the laboratory, it has been prepared by the reaction of glycerol with oxalic or formic acids. Allyl alcohols in general can be prepared by allylic oxidation of allyl compounds by selenium dioxide. Allyl alcohol is converted mainly to glycidol, which is a chemical intermediate in the synthesis of glycerol, glycidyl ethers, esters, and amines. Also, a variety of polymerizable esters are prepared from allyl alcohol, e.g. diallyl phthalate. Allyl alcohol is more toxic than related alcohols. Its threshold limit value (TLV) is 2 ppm. It is a lachrymator. It is classified as an