The Thiolized® process enhances a yeast’s ability to biotransform compounds found in malt and hops to unleash thiols — flavor- and aroma-active compounds reminiscent of grapefruit, passion fruit, and guava. Many brewers who include dry hopping in their processes are already familiar with the concept of biotransformation, or the development of new aromas and flavors due to yeast interacting with hop compounds.
WHAT ARE THIOLS AND WHERE DO THEY COME FROM?
Volatile thiols are highly impactful aroma compounds that evoke grapefruit, passion fruit, and guava and are found in a variety of tropical fruits, wine grapes, and hops. These thiol compounds exist in two forms — free forms, which are highly aromatic and volatile, and precursor forms. The precursor forms, abundant in malt, are non-aromatic and require yeast with β – lyase biotransformation activity to release them. Hop varieties vary widely, not only in the amount of thiol compounds, but also the percentage that are in the non-volatile precursor form. New World hop appear to be the high in free thiols, which contribute to their characteristic tropical fruit aromas. The precursor for 3‑sulfanyl-1-hexanol, a thiol known for its intense grapefruit and passion fruit aromas, is abundant in barley, but does not reach sensory thresholds until converted to its free form. In beer and wort, the overwhelming majority of these thiol compounds are in precursor form (1000-fold!) and are a stockpile of aroma potential with a yeast capable of biotransforming them to the free volatile and aromatic thiol compounds.