Kettle Sour Yeast Harvesting

[6midgets]

I have a local brewery whose kettle sour beer i enjoy. I noticed that every time i drink one there is a little yeast in the bottom of the can. Could harvesting this yeast and growing it into a pitch-able starter give me a yeast more suited for low Ph beers? I've had low attenuation issues in my first two attempts at kettle sour beers. Could this be a viable solution?

 

[cactusgarrett]

Are you sure their canned product isn't pasteurized before bottling or that they don't add a separate yeast for carbonation? You could reach out to the brewery itself and ask them a few questions on it. I do this when i'm curious about using dregs of a given beer, and most breweries are pretty forthcoming with that info.

 

[jjw5015]

Ya they may be souring with lacto and then fermenting with clean yeast, so you may end up with a starter of US-05.

 

[6midgets]

Yeah the main goal here is to find a low pH tolerant sacc strain. I sour with Lacto so if it has some in there no big deal.

 

[shanecb]

Maaaaybe. Sacc could adapt to lower pH environments but it takes multiple generations of gradually lowering the pH of the fermentation media. I'd more bet that the yeast in the cans is poorer health from the super lowered pH environment, and was a "regular" culture they added. When I kettle sour I just pitch around 10% more yeast than I normally would to help with attenuation.

 

[6midgets]

Update. I harvested yeast from three different commercial kettle sour beers. I made a 500ml starter, cold crashed, then decanted. Then i stepped it up to a 1 liter starter, cold crashed, decanted. last night i stepped it up to a 2 liter starter. It's now on the stir plate and its looking pretty healthy. I'm brewing a kettle sour tomorrow night i'm gonna try it in.

 

[shanecb]

Let us know how it goes!

 

[jfolks]

Although I’m excited to hear your results, this seems like a potentially bad idea to me. Sometimes dregs are not from primary fermentation but from bottle conditioning yeast. Ex: if this is CBC-1, then expect a bad homebrew. You shouldn’t have any problem attenuating pre-soured wort in the first place. You just need to pitch a healthy active starter with lager pitch rates. Some strains might work better than others - I’ve had great success with german ale and fermentis saison. If you really want to acclimate the yeast to a low ph environment (which really shouldn’t be necessary) then why don’t you acidify your starter with lactic or phosphoric acid to 3.9 ph or so?