2 weeks ago I brewed a scottish 70 type beer. For some reason I decided I would use phosphoric acid instead of my usual lactic. Long story short, for some reason I WAY undershot my mash pH down into the 5.1 range. I attempted to adjust with hard tap water and managed a pre boil pH of 5.28 or so. Fast forward 2 weeks - time for the keg. It tastes too acidic, too tart… not “sour” - but not on point. I checked pH of the finished beer and it is 4.0.
It is not where it needs to be as I was hoping to send it in to NHC. I kegged 3 gallons of it in a smaller keg I have and just poured the other 2 gallons down the drain. Now, here are my two questions:
1.) I have heard people talk about adding lactic or phosphoric to finished beer where the pH is too high. However, I have not seen much on trying to raise the pH of a finished beer. Could I add baking soda or something do you think and “fix” the beer now that it is in the keg?? Anyone do this or have any strategies or success?
2.) I also may try to rebrew it - although, time is getting a little tighter than I would like. I harvested a couple jars of yeast from the beer. Assuming everything else about the beer was on point, sanitation was good, etc… is there any reason reusing this yeast in another batch (where pH issue is corrected) would be a concern? Any reason they would be compromised due to the lower pH? Buying new yeast would likely cost me 5-7 more days or more. I could possible redrew it tomorrow with the harvested yeast.
** In regard to the actual problem - pH - the phosphoric was OLD (2012). I should not have even used it - stupid on my part. I ALWAYS use lactic and ALWAYS hit my pH with it. Thinking maybe evaporation changed the pH of the phosphoric and made it more acidic than the 10% on the label.
I’ve raised with baking soda after the fact on stouts and porters before I finally started mashing higher. But I use all RO water, which easily tolerates the sodium from the baking soda. If you’re using your tap water that can be dicey without knowing your water’s Na content. What I did was enter the grist and volumes into Brunwater and add baking soda until I raised pH the amount I wanted to. I then mixed the baking soda with a small amount of boiled, cooled water, added to an empty purged keg, then close transferred the beer onto the baking soda mixture in the empty keg to get good even mixing. Worked pretty well.
Sodium should be no big deal… it was only around 10 or so in the B’run water profile. I was originally going with a 60% RO dilution to my tap water and shooting for something closer to 5.45-5.50 for mash ph. Good call on plugging it back into B’run water to determine amount.
4.0 might not be too crazy, that Weyerman pH in the Brewhouse slideshow (peddling their acidulated malt) quotes English ales as 4.0-4.2. Could always bust out the meter and try it in the glass to see how you like it.
It might be on the bottom of the “range” - but it is definitely something that comes through - and not in a good way. Right now it is kind of the defining characteristic of the beer. I can tell the beer tastes good in the back ground, but there is a sharpness to it that just throws it off.
I will try to add a bit of baking soda to it with boiled water and see if it smooths it out.
Seeing that the pH is probably not far off from where it should be gives me some hope and makes me fairly confident that the yeast should be perfectly fine to use again as well.
Update - Took HoosierBrews advice. Went back into B’run water. Adjusted the % strength of my phosphoric acid up to 23% instead of 10% which gave me the mash pH I actually hit (5.1 range). Added baking soda into the program until it gave me a 5.4 mash pH… .5 grams per gallon took it up 3/10ths of a pH point.
So, Boiled up 1-2 ounces of water in the microwave. Added 1.5 grams of baking soda, put it into the 3 gallon keg of Scottish… 2 days later - tasted it and checked pH. pH went from 4.0 to 4.28 and the taste is right on - worked like a charm. Totally new beer - aroma is better, malt comes through, smooth, no acidic bite. Crazy what a difference something like that can make!
Just an update on this beer… I sent it in to NHC regional in St. Louis. It ended up scoring 39 points (highest of the 5 beers I sent) and making Mini BOS. Unfortunately, it did not advance. Scored higher than the 3 I had that did advance though.
So, long story short - it is possible to “save” a beer with messed up pH - post fermentation. At least in this circumstance anyway.