The human tongue is very susceptible to sourness and hence standardization of acidity is the first step towards standardization of process. Simple advice would be to use acid blend (a mixture of citric acid, malic acid, and tartaric acid) to reduce the pH and add Calcium Carbonate (CaCO3) to increase it. Avoid sodium carbonate (baking/cooking soda), as it can give a slightly salty taste.
6 things to keep in mind while measuring pH of home brew
However, a few additional aspects need to be taken into account:
- The fermented beverages are a blend of organic acids and long-chain molecules. As a result, an ordinary diode-based handheld pH meter will give erroneous readings. It is always good to measure Total Acidity (using the titration method) along with a simple pH reading.
- Carbonic Acid formed due to dissolved CO2 can also impact the reading. Hence, it is recommended to de-gas them before testing. Wines are usually filled using a vacuum bottle filler so that they are de-gassed and tastes less sour.
- Litmus paper: Although it is easiest, I would not recommend it. The pigments in the drink interfere with the readings. Also, color chart reading is often subjective and prone to a lot of errors. So, a calibrated digital pH meter is recommended.
- Acidic medium is preferred by yeast and lactobacillus as it retards the growth of molds and other harmful microbes. This is the reason why most artisans will measure the starting pH (acidity in wort and in the fresh must) as well.
- In wines, the pigment color stability is linked with optimal pH.
- Please calibrate the equipment and reagents before testing.