I recently bought a pH meter and have been tooling around with it. On my first few batches, Brunwater was spot on for mash pH and I figured I wasted my money buying a meter. However, today I brewed a pre-pro lager using RO water as a base (like I always do since my water sucks for brewing pale beers) and built it up using Brunwater. My mash pH turned out high (in the 6 range) and I had to add a few cc’s of lactic acid to get it to an acceptable level. I was really surprised by this. Any thoughts?
When did you last calibrate the pH meter?
Immediately before I used it. 2 standards. Weird, huh?
Any acid malt in that grist? I’m now hearing that the acid content of Weyermann’s and Best’s acid malts differ by a factor of 2. With that said, I’m assuming that there was some form of acid that was planned for that mash since a Pre-Pro grist would be kind of light and would need a bit of acid, even with RO water.
I use RO water too, with my light beers I shoot for 3% acid malt and ~1/2 tsp of calcium chloride per 5 gallons. I’m always right around 5.2
Nope, no acid malt in the mash- just 6-row, corn, and carapils. No biggie adding some lactic acid. That’s why I bought the pH meter, right?
Bru’n’water usually predicts a high pH for my lighter beers, even when using RO plus some salt additions; generally, I, too have to also add a few milliliters of lactic acid to reach the correct pH.
All that to say I think your finding is perfectly normal.