THE LAST WORD

摘要

I'm a student who has recently developed an obsession with home-brewed beer, so I hope I can offer some insight. Nearly all beer contains hops. This provides the bitter taste and also acts as a preservative (some natural deodorants even use hops for its antimicrobial action). Hops contain isohumulones, which provide part of the bitter flavour - and this is where the problem with light arises. When UV light hits these compounds they decompose, leading to the creation of free radicals that react with sulphur-containing amino acids. The product is a thiol - the sulphur analogue of alcohols -and this leads to a "skunky" flavour, so called for obvious reasons.