Ideally, you want a mash pH of 5.2–5.6 when you mix the water and grains. You might recall from high school chemistry class that pure distilled water has a pH of 7.0, but most municipal water sources have a higher (slightly alkaline) pH above 7.0, due to minerals they pick up from ground and surface sources.

What happens if your mash pH is too high?

It’s commonly accepted that a high mash pH can result in less efficient conversion of starches into fermentable sugars while also leading to the extraction of astringent compounds from malt and hops.

Do I need to adjust mash pH?

Mashing in the ideal pH range helps to promote better conversion, a cleaner finish, and a more balanced overall beer. If you make no pH adjustments, your pH is likely to be higher than the recommended range of 5.2-5.6. pH is commonly adjusted (decreased) with either lactic acid or phosphoric acid.