My Water Test

I just got my water report back from Ward Labs. I think I see two things that I should do; add lactic acid to my mash and some epsom salt to my kettle. Am I on the right track? Is there something else I should do?

pH - 8.1
All measurements are ppm
Sodium, Na -59
Potassium, K- 2
Calcium, Ca - 8
Magnesium, Mg - 2
Total Hardness, CaCO3 - 28
Nitrate, NO3-N - 0.1 (SAFE)
Sulfate, SO4-S - 5
Chloride, Cl - 15
Carbonate, CO3 - 6
Bicarbonate, HCO3 - 147
Total Alkalinity, CaCO3 - 131
Total Phosphorus, P - 0.95
Total Iron, Fe - < 0.01
"<" - Not Detected / Below Detection Limit

Yeah, you've got fairly alkaline water - it might be a little tricky to get your mash pH down. Since you've got such a small amount of just about everything except bicarbonate I'd probably first add some gypsum and/or calcium chloride (maybe a little epsom salt, but be careful - Mg can be tasted if it gets too high). The extra Ca will help lower the residual alkalinity and will probably get your mash pH low enough for medium to dark beers. For lighter beers you then may need to add some acid or dilute with RO/distilled water.

Your water is essentially a solution of sodium bicarbonate and presents you with two potential problems. The first is the sodium level which is highish at 59 but this is not nearly so much a potential problem as the bicarbonate with which it is paired (alkalinity of 131). The sodium you might be able to live with but the alkalinity will have to be dealt with. Conceptually, the easiest way to do this is to dilute say 4:1 with RO water. This would reduce the alkalinity to about 26 and the sodium to about 12. It will also, of course, reduce the already low calcium level to 1 and the chloride to 3 so that those would have to be supplemented. See the Primer.

The other way to tackle the alkalinity is to neutralize it with acid. As you have 131/50 = 2.6 mEq/L alkalinity you will need 2.6 mEq/L acid to neutralize it and that means there will be 2.6 mEq/L of the cation of the acid in the treated water. This can be a good thing if you are trying to boost the sulfate or chloride but if not then a flavor neutral acid such as phosphoric can be chosen. Trying to go the whole distance with lactic may result in lactic flavor but might not. You'd have to experiment.

Don't worry about magnesium as malt contains plenty of this.