Master Brewers Podcast

It is well known that hop-forward beer styles exhibit tropical fruit aromas. These aromas are conferred by a range of hop-related volatile compounds, including polyfunctional thiols such as 3-sulfanylhexan-1-ol (3SH) and 4-methyl-4-sulfanylpentan-2-one (4MSP). These compounds are present at relatively high concentrations in hops and are extracted into beer during dry-hopping. Polyfunctional thiols are also abundant as non-volatile glutathione and cysteine conjugates in hops, and to a lesser extent can be found in barley (and therefore, malt). These conjugates are cleaved into amino acids and free thiols by enzymatic activity of yeasts, thus bound precursors may represent an important pool of tropical fruit flavor in beer, particularly in beer styles where dry hopping is minimal. In order to successfully liberate this pool of flavor, yeast with strong carbon-sulfur ß-lyase activity are needed. In wine research it has become evident that only a small number of commercial Saccharomyces cerevisiae starter culture