If you’re a hop head you’ve heard terms like Myrcene, Geraniol or Linalool, these are forms of terpenes and are fairly well documented and measured within hops and their oil makeup. But you probably heard the word Thiol used a lot in the last few years, especially when talking about hops & biotransformation. With the boom in craft beer there has been a lot of research around hop aromas and Thiols are one of the More! recent areas of study when it comes to hop aromas. Essentially a Thiol or Polyfunctional Thiol is the chemistry term for an organosulfur compound that contains a sulfhydryl group along with more than one organic functional group (ex. 3‑sulfanyl-1-hexanol). Or In layman's terms depending on a specific Thiols makeup it can smell like anything from grapefruit to garlic and even roasted coffee etc. Thiols exist in two forms either Free (Aromatic & Volatile) and Precursor/Survivable (Unlocked during biotransformation). Some of the More! popular Free Thiols are those produced from southern hemisphere hops that give off tropical fruit aromas.