Bit by Brettanomyces?

Anyone ever get a nasty smoke/burnt rubber flavor from an all-Brett fermentation?

I set out to make a 100% Brett IPA using The Yeast Bay’s Amalgamation Brett blend. I made a 1L starter, but only gave it 2.5 days on the stir plate. I think I underpitched, in other words.

Brew day went normally, but I was sufficiently alarmed by the 2-day lag time that ensued that I pitched an additional dose of Brett slurry left over from an IPA I’d made with yeast from one of Evil Twin’s Brett IPAs. After I did that, fermentation took off like a rocket. I pitched at 65F and then ramped to 68 after three days.

The beer is still at high krausen, but the hydrometer sample smelled funny and tastes like burnt tires.

I’m guessing this is a consequence of initially underpitching, but will this awful flavor ago out? I’m cool with giving a beer time but I’d rather not wait three months and then have to ditch the batch. Should I dump it or give it a chance?

That’s not normal.

Brettanomyces can produce burnt rubber, but usually only with lots of ferulic acid and a very phenolic yeast. Without phenolic precursors, it should not do that. I suspect a contaminant in the slurry that caused it, either a wild yeast or a bacteria. Interestingly, young lambic often has a burnt rubber flavor that is eventually metabolized, so there is hope that it can be transformed. Give it a few weeks and see if there’s an improvement. Even butyric acid can be metabolized by brett, so give it a chance.

Next time you use it, don’t be alarmed by a 5-7 day lag period. Brett tests your patience, but that’s totally normal due to the slower metabolism. A huge starter can help, but if your sanitation is good, a long lag period with brettanomyces is just fine.

Ok, I will give this nasty flavor a chance to age out…even if my instincts are screaming to just dump it. Thanks, porkchop.

Hope it ages out for you! Keep in mind, lambic is usually aged from 1-3 years, so who knows how long it takes for burnt rubber to age out of this kind of beer. I’d at least let it get through active fermentation to see if it improves. If not, I probably would dump it. But during active fermentation, brettanomyces can be… weird. I personally have not gotten this off flavor with brett, Amalgamation has been really fruity/citrusy in primary.