What We Already Know

Fortunately, there is information about thiols available to help guide brewers. The research reported by Steinhaus adds to the list of varieties that contain 4-mercapto-4-methylpentant-2-one (4Mmp)—also known as 4-methyl-4-sulfanylpentan-2-one (4MSP)—AS well as verifying some that do not. Combined with other reports, here’s what we know about 4MMP/4MSP:

High levels of 4MMP/4MSP: Citra, Simcoe, Eureka!, Summit, Apollo, Topaz, Mosaic, Ekuanot, Galaxy, Nelson Sauvin, Vic Secret. Significant levels of 4MMP/4MSP: Zeus, Cluster, Chinook, Cascade, Centennial, Amarillo, German Northern Brewer, Hallertau Blanc, German Cascade, Mandarina Bavaria, Polaris. Measurable but low levels of 4MMP/4MSP: Bravo, Calypso, Denali, Galena, Lemondrop, Sorachi Ace, Super Galena, Willamette, Halltertau Tradition, Herkules, Perle, Taurus, Tettnanger, Styrian Golding, New Zealand Pacific Gem. Perhaps Saaz (found in one study, not in another). No 4MMP/4MSP: Hallertau Mittelfrüh, Hersbrucker, Hull Melon, Magnum, Saphir, Spalter Select, Bramling Cross, East Kent Golding, First Gold, Fuggle, Pilgrim, Progress, Wye Challenger, Wye Target. Researchers are only beginning to examine other thiols as closely. For instance, they found that Nelson Sauvin, Citra, Simcoe, Cascade, Mosaic, and Amarillo all contain significant amounts of free 3-mercaptohexan-1-ol (3MH). Scientists in both Belgium and Japan have identified grapefruit-like 3-sulfanyl-4-methylpentan-1-ol thiol in beers made with Amarillo, Hallertau Blanc, Nelson Sauvin, Mosaic, and Ekuanot. The discovery of still other thiols confirms there is much more research to be done.