Wanted some feedback before I go ruin a batch of wort... My lacto bugs decided to get a little extra happy and drop the pH of my wort from 3.8 last night to 2.9 this morning when I raised the fermentation chamber temperature a few degrees. Since I am going after a tart gose style beer, and still need to pitch my yeast, I would rather it not be quite so acidic. I am thinking about adding some sodium bicarbonate (baking soda) in water to raise the pH to around 3.4-3.6. (My math says about 0.5 oz bicarb should do it). Thoughts?
Wait, are you saying your wort started off at 3.8? If so, I wonder if your meter needs to be calibrated (which should be done before each use anyway). Or are you saying you had already soured down to 3.8 initially? Anyway, yes, Baking Soda could be used to raise the pH.
Already soured down to 3.8, sorry should have been clear about that. My starting pH before lacto pitching was around 4.9 (I used some acidulated malt in my grain bill).
It's up to you of course, but I'd recommend mashing at a more traditional pH, and then pre-souring your wort with lactic acid. For mash efficiency if nothing else.
I actually did. This is planned on being a more tart gose, so I mashed in without the acidulated malt for 60 minutes, then added the acidulated malt, and mashed for an additional 45 minutes. Boiled for 60 minutes, then pitched my lacto starter and held at 95F for now about 48 hours. Typically I don't reboil when I hit my target pH, just pitch my yeast and hops and all is well. However with a pH of 2.9, I am concerned about the yeast not surviving, off flavors and being too tart, hence the question about the bicarb. I'll plan on doing that tonight and report back on the results!
I always boil after kettle (really keg) souring, so that my regular fermentation equipment isn't exposed to lacto. Not that it's a huge risk, and lacto isn't particularly hard to kill, but I do it anyway. That would concern me too.
I don't have any advice to offer, but I am curious which strain of lacto you used. That is impressive souring.
Bootlegs sour weapon pack, so usually I use the Sour Weapon L and P. Makes for really tasty sours. This is one I did recently with raspberries, blackberries and blueberries.
Just to make sure we're on the same page, for the beer that went down to 2.9 pH, did you use only Sour Weapon L (a Lactobacillus blend) or did you also add Sour Weapon P (Pediococcus)?
Okay well I think that explains the low pH. Instead of adding baking soda, have you considered doing a 100% Brett fermentation? Brett can handle the low pH, and it will also clean up any diacetyl that the Pedio makes. Tagging in @EvenMoreJesus for any thoughts he might have.
Yeah . . . I would definitely recommend using a brettanomyces species for this fermentation, as most S. cerevisiae strains have difficulty fermenting anything under a pH of 3.0. FWIW, brett is usually OK until a pH of around 2.0. I would also think about blending this end product with a similar beer that isn't soured to reign in your pH.
I might do a blend of the end product, wouldn't be hard to make another batch that isn't 'soured' at all. Great advice!
