Since going all-grain, I've been consistently seeing very low efficiency (sub 70% with a single batch sparge), and very high attenuation (85%+ AA in all malt worts with a 60 minute 150-153F saccarification rest). I've tried crushing finer and finer, even going below a 0.020" mill gap.
I'm thinking that my issue may be with mash pH. I've been using ColorpHast strips to measure pH, aiming for a reading of 5.0 - 5.2 at mash temp, but it's pretty hard to read the strips accurately. According to Greg Noonan, alpha amylase has an optimum pH of 5.7, while beta amylase has an optimum pH of 4.7. Could a low mash pH be favoring beta amylase over alpha amylase, resulting in poor starch conversion and a low-dextrin wort?
I'm thinking that my issue may be with mash pH. I've been using ColorpHast strips to measure pH, aiming for a reading of 5.0 - 5.2 at mash temp, but it's pretty hard to read the strips accurately. According to Greg Noonan, alpha amylase has an optimum pH of 5.7, while beta amylase has an optimum pH of 4.7. Could a low mash pH be favoring beta amylase over alpha amylase, resulting in poor starch conversion and a low-dextrin wort?