Here's an easy excel tool to calculate the amount of different acids you would need to add to your sparge water to change its PH to a target value, based on the following imputs: - Specific gravity of each acid (mg/ml) This is only used/required if you wish to know the volume of the acid, calculated in the very bottom on the tool. I have added few values that I could find. The ones I couldn't find I used 1000, which is the gravity of water.
-Acid concentration (%)
This is the concentration of the acid. It is usually shown on the label. I used 88% for Lactic and 10% for phosphoric, which I have bottles. The other values different than 100% I got on the web. You will need to make sure you enter the correct value of what you plan to use.
This is from your water report. In order to use this tool, you need to know this info.
This can be from you water report of your PH meter. I use the value I get from my PH meter, which I take every time I brew. This is the start PH.
-Water volume (gal)
The amount of water you will be treating with acid, or your sparge volume
This is your final PH or target PH, which you want your sparge water to be at, so you can avoid tanin extraction.
If your water PH is already low, like below 6.5, I wouldn't add anything. Finaly, the excel tool can be found and downloaded HERE or at the menu "technical stuff"
If you have any questions, feel free to use the contact option at the top menu.