Learn More About the PH in the Brewing Process
We talk about the pH for the water used in brewing, for mash, wort and even for finished beer: each of them has a different impact on beer, but the most important for those who brew in the all grain method is the pH during mashing. In particular, we want this to remain between 5.2 and 5.5, but preferably closer to the lower end of the range.
A pH close to 5.2 has advantages:
- Improvement of enzymatic activity during mashing, which leads to a better conversion of starches into sugars
- Reduction of the pH in the wort promotes the health of the yeast during fermentation and inhibits bacterial growth
- Increased extraction rate of boiling hops
- Greater precipitation of proteins and polyphenols, both during the cold break and in post fermentation
- Reduction of chill haze and clearer finished beer
- Increased aroma stability and clarity in aging
It is difficult to know in advance the pH of the mash: many commercial breweries are able to do it because they always make the same recipe, with the same ingredients and in the same conditions.
Here are some of the factors that affect pH:
Water: The chemical composition of water plays an important role in determining the pH of the mash, especially due to calcium, magnesium, carbonates and bicarbonates. Most of the waters are alkaline, so they tend to bring the mash above the ideal range (5.2-5.4).
Malts: Malts tend to be acidic, which means that they lower the pH of the entire mixture. This is especially true for darker malts, which is why dark beers require limited pH correction. Unfortunately, the acidity of the malts varies widely and is not measured and made known, therefore it is very difficult to predict the mash's pH in advance.
Since it is impossible to predict what the pH of the mash will be for a recipe, you will have to measure it and then correct it in each batch. In most cases the measured value will be too high and you will have to add an acid or buffer agent to the beer to correct it.
Here are some options:
- Lactic acid - An organic acid produced by bacteria. It is a liquid solution at 88% by weight. It is added until the desired pH is reached; generally it mixes well with the aromas of beer in the small quantities required to correct a typical mash.
- Sour malt - This is typically pilsner malt acidified using lactic acid and contains approximately 3% of the acidity weight. It is mainly used in Germany to comply with the strict purity laws (Reinheitsgebot) which prohibit the use of ingredients other than malt, water, yeast and hops in beer.
- Phosphoric acid - An inorganic acid widely used for soft drinks. It replaces the bicarbonate with the phosphate, increasing its content in the wort.
- Sulfuric acid - Used by many commercial breweries, they are usually not available in retail. It can be dangerous to handle them (they are both highly caustic) and are not recommended for home use, they also generate significant off flavors if used incorrectly.
So always keep in mind that for all your recipes you must reach the optimal PH level. Take notes of the various measurements so that you can compare them in the future to simplify and speed up the process.