Ask Mr. Wizard

Brewing Water Tweaks

TroubleShooting

Robb Van Putte — Staunton, Illinois asks,
Q

I am about to brew my first all-grain batch of beer with reverse osmosis (RO) water. I used the EZ Water Calculator spreadsheet to determine mineral additions to the water. Since I am using RO water, I entered in zeros for all of the starting mineral contents. After entering in the grain bill and total water required for the brew day, it determines the amount of salts to add to the water. This, of course, is based on how the grains affect the pH of the mash as well as salts added, with the goal of predicting a mash pH in the range of 5.4–5.6. However, the calculator does not recommend adding any calcium carbonate or sodium bicarbonate to the mash or sparge water. So, here’s my question: Isn’t it recommended to add some alkalinity to the water in order to buffer against pH changes that fall below the optimum? Or is it really dependent on the grain bill, the grist ratio, and the salts added to the strike and sparge water? Here’s the grain bill:

6 lbs. (2.7 kg) pale ale malt
2.25 lbs. (1 kg) Munich malt (10 °L)
0.5 lb. (227 g) caramel malt (60 °L)
0.25 lb. (113 g) Carapils® malt
0.25 lb. (113 g) chocolate malt
0.38 lb. (172 g) white wheat malt

A
Grain bill, grist ratio (mash thickness), and salt additions all affect mash pH. I am not going to address specific how-to details related to the EZ Water Calculator in this answer, but
Response by Ashton Lewis.