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Active Member
Feb 1, 2019
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Hey, just posting some cool/ nasty photos of a recent infection in a witbier I brewed about 6 weeks ago.

While I really wanted to just put it in the basement for 6 months and see, I tasted it on two separate occasions and it was pretty awful, and then the large amount of top layer growth finally convinced me. Plus, it was just some leftover ingredients put together for a random recipe. Anyone seen something like this before? I was thinking acetobacter since it was so sour smelling and intense, however my new theory is that bacteria got it when my krausen blew off the airlock lid for several hours before I got home. I also noticed some blue/ grey mold on the inside of the fermentor neck. Also it went from OG around 1.035 to SG 1.002, so it attenuated and had alcohol, making a wild yeast infection seem unlikely.


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Could be wild yeast and/or bacteria. There's no way to identify it just by looking. Pellicles are common.

Many types of wild yeast and bacteria are very alcohol-tolerant. Some wines and beers are made entirely with wild yeast -- they fully attenuate, even moreso than domesticated yeast in many cases.

Use a blow-off tube ;)

Yeah, who knows what it was. I thought it could have been wild yeast contamination, especially since I've had some wild yeast starters in the house that I harvested. I'm brewing a beer with that wild yeast now, so maybe a taste/ smell/ pellicle comparison will confirm or refute that potential source.