Changes

Many sour beer producers use pH to help determine how "sour" their beer is in relation to a set goal, previous batches, or commercial examples.

In chemistry, pH is the negative log of the activity of the hydrogen ion in an aqueous solution. Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. Pure water has a pH of 7.

pH is best tested in sour beers using a [[PH Meter]] and is most useful for biological parameters. Cells live or die based on pH, not TA. This means pH should be used when testing sanitizer, sour worting, starter cultures, etc.

When attempting to use pH for sensory parameters - how sour something tastes - the measurement falls short. Humans perceive acidity from tasting acids, not H+ ions. In a strong acid, the amount of acid is always proportional to the amount of H+ ions. However, lactic acid - the primary acid in sour beer, is a weak acid. For various reasons a weak acid does not completely ionize / dissociate.

Kara Taylor at White Labs has done a reasonable amount of professional sensory panels showing the correlation between TA and perceived sour taste, as well as showing no correlation between pH and sour taste. Her full presentation, where most of this information was sourced, is available to any attendee of the 2015 Craft Brewer's Conference.

1. pH Meter with Automatic Temperature Correction

1. Calibrate pH meter

8. Use the following formula to find Titratable Acidity:

The number you get is TA in grams/L.

It may be best to compare the ratio of Titratable Acidity / Final Gravity as sweetness counter-acts acidity in sensory experiments.<ref>Kara Taylor, White Labs - CBC 2015 Presentation "Sour Beer is More than pH"</ref>