btbnl
Well-Known Member
I just brewed a three of my regular BIAB batches, using a freshly-calibrated pH meter and allowing the samples to cool before measuring.
Normally I unwrap the mash after 30 minutes and take the pH, gravity and temperature, and invariably the pH is within 0.1 of the Bru'n water calculations (targeting pH 5.4 in all cases).
On this occasion I waited till 60 minutes to take the readings. Both batches that included 3ml 85% phosphoric acid registered pH 4.9, whereas the batch that had no phosphoric acid registered the expected pH 5.4. Again, previously when I've measured the pH at 30 minutes with exactly the same recipes and water additions they've all been at pH 5.4 +- 0.1.
Any ideas what might be going on? Does the pH really change that much during the mash with phosphoric acid? Incidentally, I didn't see any impact on the efficiency.
Details:
Oakland CA water: Ca 9, Mg 3, Na 11, Cl 6, SO4 9, HCO3 34 mg/L, pH 8.9
Batch 1: 20lb 2-row, 4lb Vienna, 1lb Carapils, 1lb Crystal 30 in 8.25 gallons with 2 tsp CaSO4, 1 tsp CaCl, 3ml H3PO4 (85%) => 60 min pH = 4.9
Batch 2: 9lb Maris Otter, 1lb Crystal 80 in 8 gallons with 2 tsp CaSO4, 1 tsp CaCl => 60 min pH = 5.4
Batch 3: 7lb 2-row, 3/4lb Carapils, 1/2lb Vienna, 1/2lb Crystal 10 in 7.5 gallons with 3ml H3PO4 (85%) => 60 min pH = 4.9
Normally I unwrap the mash after 30 minutes and take the pH, gravity and temperature, and invariably the pH is within 0.1 of the Bru'n water calculations (targeting pH 5.4 in all cases).
On this occasion I waited till 60 minutes to take the readings. Both batches that included 3ml 85% phosphoric acid registered pH 4.9, whereas the batch that had no phosphoric acid registered the expected pH 5.4. Again, previously when I've measured the pH at 30 minutes with exactly the same recipes and water additions they've all been at pH 5.4 +- 0.1.
Any ideas what might be going on? Does the pH really change that much during the mash with phosphoric acid? Incidentally, I didn't see any impact on the efficiency.
Details:
Oakland CA water: Ca 9, Mg 3, Na 11, Cl 6, SO4 9, HCO3 34 mg/L, pH 8.9
Batch 1: 20lb 2-row, 4lb Vienna, 1lb Carapils, 1lb Crystal 30 in 8.25 gallons with 2 tsp CaSO4, 1 tsp CaCl, 3ml H3PO4 (85%) => 60 min pH = 4.9
Batch 2: 9lb Maris Otter, 1lb Crystal 80 in 8 gallons with 2 tsp CaSO4, 1 tsp CaCl => 60 min pH = 5.4
Batch 3: 7lb 2-row, 3/4lb Carapils, 1/2lb Vienna, 1/2lb Crystal 10 in 7.5 gallons with 3ml H3PO4 (85%) => 60 min pH = 4.9