Additions for Rainwater.

[bigmunchez]

Thanks for the info.
My mash ph was 5.17 at 45 minutes into the mash.
Ph meter is temperature compensated [emoji106]

just to be clear, even with an ATC pH meter, you still need to measure at room temperature. There’s two things going on. The probe itself behaves differently at different temperatures. This is what the ATC compensates for.
But the actual pH value also changes, as temp goes up, pH drops. The ATC doesn’t allow for this.
When you see references to target mash pHs they should all be based on the sample being measured at 20C. So when you measure at room temp and get a pH of 5.2, the actual pH of the hot mash will be lower but you can just ignore that because we measure and discuss pH at room temperature.