Yogurt to Sour

Tf0498 · Jan 24, 2020

Hey All!

I'm curious about Kettle souring with Yogurt. I've heard a lot about this going around with local breweries. Just curious if anyone has any tips/specific yogurts they like to use.

Really going for highly fruited sours like The Answer

Cheers

Nosybear · Jan 24, 2020

Just find one with "probiotics." I'm not familiar with that beer but any lacto source will inoculate it and work fine.

thunderwagn · Jan 24, 2020

Not yogurt, but i have Goodbelly mango flavored probiotic drink and it works great. You can search out more on it on the Milkthefunk wiki, and/or facebook group.

Mark Farrall · Jan 24, 2020

I've also used the probiotic drink (Yakult) approach and it's worked well.

The main thing to think about with the yoghurt is how good the manufacturer is with only including the bacteria they list. Lactobacillus is basically anerobic, so it doesn't produce anything other than lactic acid while you're kettle souring (unless you do something truly unexpected).

If your yoghurt manufacturer isn't fastidious you may get some aerobic bacteria as well. They're the ones that may give you some of the more pungent odours/flavours. That's also the challenge with the sour mash approach that uses the lactobacillus on your grains.

You can protect against this by keeping the oxygen to a minimum, generally this is using cling film over the kettle.

And I've drunk a bunch of great kettle sours that used yoghurt, so I don't think it's that big a risk. Listening to the brewers discuss the process they don't do anything to stop the oxygen getting in to the kettle. Which would be a bit of a challenge at a commercial level.

GFHomebrew · Jan 26, 2020

Through making sourdough and Filmjolk (fermented milk) I think I've found one culprit of this "stink" bacteria which might be a common contaminiant in the brewhouse.
A little Farty (meaning can cause some wind in ones arse) bacteria Leuconostic. I know from my sour dough research they wouldn't mind a ph of around 6 less so at 4.5 Well beer is 5.2-6 a perfect medium

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https://en.m.wikipedia.org/wiki/Leuconostoc