I’m getting ready to brew my first all grain batch. Should I just check the PH of the water prior to mashing or should I check it during the mash?
If it’s your first all grain then forget the pH. Or at most measure it only for your records. Don’t waste money on a pH meter you may never use again – at this point you may yet discover that mashing isn’t for you. But realistically, pH papers are fine. Don’t waste your money on a meter at all.
If you really want to, then check the pH both of the water prior to the mash, and of the mash itself. Also check your sparge water pH, especially if you treat it with some sort of acid. I check mine every time, and only seldom does the pH fall out of ideal. Even then it’s still well within the range considered acceptable. But I still check it anyway, mainly for my records. Realistically if it is your first mash you won’t know what to do about an off pH anyway. I’ve been mashing for 3 years now and can’t say I’d know what to do if some of the readings I regularly take didn’t fall in the right place (which they always fall into). That’s a bit of an exaggeration. I’d know where to go look up what to do, but I wouldn’t know off the top of my head.
Another thing to consider is the pH papers being made out of paper. If you get the plastic strips instead, the issues you’re probably having with paper readings will magically disappear. The paper ones soak up water which throws off the reading. Plastic doesn’t soak up water. The only potential problem with the papers is if you are colorblind. I am a bit, and sometimes I have trouble reading them, depending upon the lighting.