Onions Garlic and other fun Sulfury Flavors from

Onions, Garlic and other fun Sulfury Flavors from New World Hops Scott Bickham, Ph. D. BJCP Exam Director BJCP Northeast/International Representative Grand Master IV Beer Judge scott. bickham@bjcp. org Copyright © 2018 Scott Bickham. All rights reserved.

20 Years ago, Sulfur-Struck appeared in Brewing Technique …Plus ça change, plus c'est la même chose Original article: https: //www. morebeer. com/articles/sulfur_compounds_in_beer https: //cervezomicon. wordpress. com/2016/12/20/con-el-azufre. Spanish translation: hemos-topado-amigo-jombriguer/

Sulfur aromas in nature are often warning signs �Stagnant water �Sewage �Poisonous gases �Skunks Ethanol versus ethyl mercaptan: substituting Oxygen with Sulfur makes a compound that is added to natural gas to make it easier to detect

Sources of Sulfur in Brewing Fermentation (yeast) Brewing Process: • Mash • Boil • Chilling water Thiol compounds in hops: amino acids

Sulfur characteristics are grouped into 4 categories in Class 7 of the Beer Flavor Wheel

Second tier descriptors are more familiar terminology when evaluating aroma and flavor

DMS is only one element of a larger family of cooked vegetable flavors

DMTS can produce onion-like flavors in beer

Many popular US and “new world” hops have sulfury aroma and flavor components • S-methyl methanethiosulfonate has been identified as a potent aroma compound in Centennial and Citra hops • Sauerkraut-like flavor with a detection threshold of 5 ppm

The way the hops are processed can impact the level of sulfury and grassy flavors in beer Green: Cat urine, green grass, tomato leaves, green peppers Vegetal: Celeriac, leek, onion, artichoke, garlic, wild garlic Stan Hieronymus, “Cascade – a study in hop terroir, ” Hops (28 -Feb, 2015)

• Onion and Garlic Character from New World Hops Mercaptans are sulfur compounds with very low thresholds • They are usually formed by yeast through the metabolism of sulfur-containing amino acids • They are also found in hop oils, particularly in some varieties of New World hops • Citra and Mosaic: ‒ Used in low amounts: pear, tropical fruit or sauvignon blanc ‒ High levels: ribes, cat urine, armpit sweat, or dank (“pungent, funky and odoriferous, refers to both good weed and very hoppy IPAs”) • Simcoe and Summit: ‒ The oils found in these hops varieties include mercaptan which has an aroma like freshly cut onions (dry-hopped IPAs)

Isovaleric Acid • Sweaty, leathery or barnyard character from Brettanomyces • Valeric esters have distinctive and pleasant fruitlike odors • Perfumes and cosmetics • Methyl valerate: flowery • Ethyl isovalerate: apple • Amyl valerate: pineapple

Troubleshooting Guide for Sulfur Flavors and Aromas (English)

Summary � Sulfur compounds in beer originate from all major ingredients: malt, hops, yeast and water � Many are volatile compounds with very low thresholds, but the traditional brewing processes tend to naturally reduce their concentrations to acceptable levels � Sulfur compounds can be difficult to troubleshoot because they readily convert into other compounds in response to changes in p. H, temperature, and staling (oxidation) reactions � High levels usually indicate issues with yeast health (autolysis) or contamination by Gram-negative bacteria