Hey Oliver, greetings from Lafayette!
We've started paying attention to our Pre-Boil pH after talking with J-Ro at Tin Roof. (one of our Dead Yeast members) He counseled us to get below 5.2 for better hop utilization and flavor/aroma shelf-life after packaging. (and I think it helps with clarity too, my hot breaks have been perfect 'egg-drop soup' when I nail this, and I can read text through my gravity samples and finished beers!)
What I do is initially target my RA for the style range (from the More section of the Recipe Editor) as best I can also paying attention to mash pH of course. I use the auto-additon feature in the Water Calc based on my acid type and strength. (we use 85% Phosphoric) As a rule of thumb, lighter beers usually require about 7ml on our system for a 5gal batch. (starting with 9–10gal of full-volume strike doing BIAB/No-Sparge)
After I initially link the Calc to the recipe to pull in my additions, I go back into the Water Calc and change my target pH to 5.2, then calculate the difference between what acid amount it calls for and what I've initially put in at strike. That usually gets me very close. Occasionally I have to dribble another fraction of a ㎖ or so. But I'm usually rounding up anyway, so that is rare. I just manually put that Acid addition in my Other section on my recipe as that also gives me a brew step so I don't forget.
It would be nice if this were incorporated into the Calc though.
*We chose 85% Phosphoric after playing with Lactic and Acidulated malt. While some people caution about dropping out Calcium, we haven't found that to be a problem. (though we routinely target a minimum of 80ppm if not 100ppm Calcium ions for every brew) We bought a gallon of it and I can get you the link if you need, but I'm sure you have access to just about anything for your shop.
