I’ve become a believer that mash pH probably matters for healthy fermentation, hop expression, and even clarity of beer. However, the learning curve is high, it takes extra equipment, and makes brewday a bit more eventful. Because I was given a very expensive pH meter for free, I felt compelled to at least give mash pH a try. I didn’t want to mess with water reports, or add specific brewing salts based on my water, or getting BeerSmith, so instead I focused on using phosphoric to get the mash water pH down to the proper range (5.2 to 5.5, I believe), and that’s pretty much it.
Several batches later, I cannot get the damn pH low enough, no matter how much acid I dump in the damn thing. For one IPA, for example, I added 11 tablespoons of phosphoric acid (10%) into the mash water. And still had a pH of 5.55! That’s half a bottle, costing $4.50 per bottle. Dark beers are the same thing.
If you do brew in a bag, and begin with the full volume of water (8-10 gallons, say), this is something to consider. You will have to add much more acid to the mash than the traditional method. Further, if your tap water has a lot of “temporary hardness” (don’t ask me to explain), then you will have to add a lot of acid to get through it. Alternatively, you could use RO water from the store.
Acid malt is another option, but I think I would have to add at least two pounds, which is roughly the same cost as acid in the first place.
Next brew I plan on really dialing in the mash pH for an IPA. Stay tuned.