So, brewing a Hefeweizen yesterday.13 gallons of RO water for the mash.
Salt additions: 5.67g CaCl2
4ml Lactic Acid 88%
I also added 2lbs of Acid Malt
21lbs 3.6 oz Wheat Malt
12lbs 12.1 oz Pilsner
12.6 oz Melanoiden
1lb Rice Hulls
I mashed for 15 mins, pulled and cooled a sample to 65*, tested pH and my recently calibrated pH meter gave me a reading of 5.12 Much lower than my estimated 5.25
I proceeded with the remainder of a 60 min mash, took another sample cooled to 65* and this time I got a reading of 5.32 I took a 3rd sample and got the same result.
I rarely miss my pH estimates but in doing so, I felt taking a second and third sample at the end of the mash made good sense.
So, my question is why, and can, the pH change that much?