When your natural water is too acidic or alkaline to achieve an optimum mash pH of 5.2 to 5.8, give it a helping hand. Two easy methods exist to bring your pH in check:

• Salts — Naturally acidify the mash through the addition of calcium salts like gypsum. Calculate the theoretical amount needed via software or stir in small doses (½ teaspoon) of the needed salt and measure the pH.

• Lactic/Phosphoric Acid — For water that is seriously alkaline, bring in the heavy guns — food-grade lactic or phosphoric acid. Same approach as the salts, add small doses (a few milliliters), stir, and measure. This is great for acidification of sparge water (around 5.7).

Reducing Alkaline Water

Sometimes acid just isn't enough when you're dealing with heavily alkaline water. When this is the case you have a few choices. Boiling and cooling will cause some of the carbonate to settle out, but usually more drastic measures are needed.

The easiest method to deal with overly alkaline water is to dilute your water with mineral-free distilled or reverse osmosis water. Figure out the effect of adding pure water to your beer by averaging the mineral content. For instance, you have three gallons of water with 300 ppm alkalinity and you add 3 more gallons of distilled water. Your new alkalinity number is (3 × 300 + 3 × 0) / 6 or 150 ppm. Just remember, the effect applies to all your ions at the same time, so you may need to add some minerals back.

For larger batches of water, dilution may not be practical. Treating your brewing water with slaked lime Ca(OH)2 and monitoring the pH removes much of the carbonate. Look online for further instructions if you feel this is the course of action for you.