Thiols are forming part of extensive research into unlocking those beautiful aromas available from your brewing ingredients. Thiols are sulphur compounds that can be unlocked to release some impressive tropical fruit aromas. However, be warned, it also has the potential to unlock unwanted flavours!
The desire for hop-forward beers has now diverted attention to how to get more of those tropical fruit aromas into the beer’s aromatics. Can this be done by unlocking the thiols in ingredients such as hops and malt?
What are Thiols?
Thiols are commonly found on some tropical fruits, wine grapes, malt & hops. They are organic aroma compounds that can be unlocked by enzymatic reactions. This is done during the mashing process or during active fermentation as biotransformation. The enzymatic activity will occur stronger with particular malt, hops and yeast types. Thiol Yeast isn’t currently available in the EU & UK. Regulations don’t permit yeasts to be sold that are genetically modified too. Unlike we are seeing available in parts of the US already.
The aroma potential of malts and hops has just been given an enormous boost. It’s an exciting time for experimentation in brewing. Drawing on knowledge from the wine industry, we see the knowledge being applied to brewing. Thiols are concentrated in grape skins, so we see brewers using dried grape thiol powder to unlock aromas.
Biotransformation
Biotransformation is a related new topic for craft brewers. Only recently have hops been added during active fermentation to achieve these biotransformations. Biotransformation is caused by yeast activity and hops compounds resulting in new flavours and aromas. We have had good success in Our Brewery dry hopping 6-8 points off final gravity.
The use of thiols can be considered as the conversion of aroma compounds as just explained or unlocking & releasing from precursor forms. The activity to release or unlock the precursor forms need β – lyase activity to release them. Mash hopping has been shown to work. Already some are reporting that different hops achieve better results. Cascade is favourably commented on as releasing and unlocking desirable thiols.
Malt thiols are an exciting development that we are very eager to explore. With such a diverse range of malts & heritage malts available now, we are keen to explore how to unlock the aroma potential in these malts. Such as, some of the aromatic malts we stock can provide impressive aromas when crushed. If the opportunity to enhance these aromas is now possible, that’s a genuinely exciting development.
How do you measure thiols?
Given the complex equipment needed to analyse thiols, it won’t be readily available to brewers soon. In terms of concentrations, they are measured in parts per trillion. Low concentrations tend to have a significant impact.
Why enhance thiols?
The demand for aroma compounds is hugely popular. It’s no surprise that hops containing these thiols are the most expensive. Many brewers are looking at ways to unlock these flavours. Yeasts are being genetically modified to have the gene IRC7, which changes the precursors into thiols and unlocks the aroma.
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