I have a two part question.
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.