I like the theory of these types of simple rules. Is this based on a sparge? I plugged the values into Bru'n Water for a recent Belgian Blond recipe.
With a full volume mash using 7.8 gallons of strike water, I get a predicted pH of 5.17. 1ml of 88% Lactic Acid would get me to a 5.42 pH and none gets me 5.55.
If I instead mash with 4 gallons and sparge with 4 gallons, and add the full 3 ml of acid to the mash water, I get a predicted mash pH of 5.26.
Since I do mostly full volume mashing, I don't really understand sparge water acidification best practices. Note, I also brew with my tap water as a starting point, so I don't really have a good feel for brewing with RO.
But if I was a new all-grain brewer brewing a light colored beer and starting with RO, I would wonder
- If I am doing full volume mashing, should I reduce or skip the lactic acid? Won't my mash pH be very low for dark beers?
- If I am doing a sparge, do I add all the adjustments to my mash water?
Personally, I really like the theory of what I see in this poster:
Brewing Water Chemistry Poster I wish it was not $50! I like the idea "If you are brewing X style of beer starting with Y type of water, add A, B and C." The fact that Salt, Epsom Salt and Chalk are on the list of salts to add and Calcium Chloride is not, is a big red flag as to the validity of the chart.