Adjusting the mash pH is a crucial step in the brewing process to ensure optimal enzymatic activity and flavor development. Lactic acid is commonly used to lower the pH, and the amount required depends on several factors such as the water chemistry, malt composition, and target pH range.
In my experience as a brewer, I have found that adding lactic acid gradually and measuring the pH after each addition is the best approach. This allows for better control over the pH adjustment and prevents overshooting the target range. Using a 1mL syringe makes it easier to add small increments of lactic acid, ensuring precision in the adjustment process.
When adding lactic acid, I typically start with half a milliliter (0.5mL) at a time. After each addition, I give it a minute or so for the acid to recirculate and mix through the pump. This helps to ensure even distribution throughout the mash and accurate pH measurement.
Once the acid has had time to mix in, I measure the pH using a reliable pH meter or pH test strips. If the pH is still higher than the desired range, I repeat the process, adding another half milliliter of lactic acid. I continue this process until I reach the target pH range, typically between 5.6 to 5.8 for most beer styles.
It's important to note that the amount of lactic acid required may vary depending on the size of the mash and the desired pH adjustment. For example, in a 10-13 gallon batch of sparge water, I usually find that it only takes one or two milliliters of 88% lactic acid to achieve the desired pH range.
It's worth mentioning that lactic acid is not the only option for adjusting mash pH. Other acids such as phosphoric acid or citric acid can also be used, each with its own characteristics and recommended dosage. However, lactic acid is commonly chosen due to its mild flavor contribution and ease of use.
To summarize, the amount of lactic acid required to adjust mash pH depends on various factors, and it is best to add it gradually while measuring the pH after each addition. Starting with half a milliliter at a time, waiting for recirculation, and re-measuring allows for precise control over the pH adjustment process. In my experience, one to two milliliters of 88% lactic acid is typically sufficient to lower the pH into the desired range in a 10-13 gallon batch of sparge water.