Controlling acidity is part of making a good beer. Acidity is measured on the pH scale, which most people know as running from 0 to 14. For home beer brewing the pH of the mash should be close to 5. If your pH level is too high, you can lower it with Acid reducing Crystals.
Modern digital pH meters, available at E.C. Kraus, make it easy to take quick and accurate readings. Make sure there's one in your beer equipment collection.