Hold the cheese: Off aromas in Amarillo SMASH brew

Cheese and beer are a match made in heaven. Just not in the same glass. I know plenty of people who love their funky flavours and bretts , it’s when the cooties show up where they weren’t invited that I start worrying. Especially when it’s a brew I was planning to enter in a competition.

Isovaleric acid — or 3-Methylbutanoic acid for short– is the fatty acid behind the distinctive, cheesy pong of smelly feet and locker rooms. It’s used in the perfume industry, where whale vomit (or ‘amber grise’ to be sweeter about it) is high-value addition. It contributes to the flavor of Swiss cheese. And also, it seems, to the flavor of the Amarillo SMASH pale ale fermenting in my kitchen

What gives? While Brettanomyces breaks down leucine (an amino acid present in both sweat and beer) into isovaleric acid it takes months to do so. It can also break the isovaleric down into the fruity ethyl isovalerate ester. Considering that I didn’t deliberately introduce it to a beer that’s only been fermenting a week, it’s more likely that the sweat-festival has other causes….

· Unsanitary conditions: some types of oxygen-loving bacteria can contribute to the development of it in beer. Yes, I oxy-cleaned the bejaysus out of everything — but as I brewed another batch this weekend, was reminded that I had my dad talking at me incessantly at chill time and maybe I forgot to sanitize the chiller.

· Past-it hops: Older, oxidized hops can bring the cheese as the alpha acids degrade. I ordered new pellets for this brew and they looked and smelled pretty good when I opened the packet, but who knows?

· Too many hops — although at 70g spread across bittering, flavouring and aroma for 19l in the fermenter, I’m not so sure.

· I just don’t like Amarillo :-( I’ve never used it on its own before but was attracted by the promise of lots of lovely grapefruit aroma and tangerine falvours…

Although all humans can detect the smell, it seems some of us are far more sensitive — as in, 10,000 times more sensitive. I’m hoping that I’m in the latter group; the promise that it fades over time will be an interesting one to track.

Originally posted on www.thiswomanswort.com