Bear with me, this is my first real scientific effort to control my brewing water chemistry. I didn't find an answer to this specific question on the site, but I might not have known all the proper terminology to do a good search.
Here's a bit of background:
I am going to brew an ESB and had downloaded the Bru'n Water spreadsheet (really awesome, I am very impressed!) and plugged in the information for this mash. I was able to match the London water profile pretty easily with a a bit of gypsum and calcium chloride added to my Chicago water, but the mash pH was higher than I wanted (5.8). I lowered the mash pH by adding a total of 5 mL of lactic acid. BUT... this lowers my residual alkalinity to +2, which is a bit low for an amber ale.
For brewing purposes, does RA serve any purpose beyond achieving the proper mash pH? In other words, when creating a water profile for a recipe, is RA really that important, or is it just a tool for determining what mash pH will be?
Here's a bit of background:
I am going to brew an ESB and had downloaded the Bru'n Water spreadsheet (really awesome, I am very impressed!) and plugged in the information for this mash. I was able to match the London water profile pretty easily with a a bit of gypsum and calcium chloride added to my Chicago water, but the mash pH was higher than I wanted (5.8). I lowered the mash pH by adding a total of 5 mL of lactic acid. BUT... this lowers my residual alkalinity to +2, which is a bit low for an amber ale.
For brewing purposes, does RA serve any purpose beyond achieving the proper mash pH? In other words, when creating a water profile for a recipe, is RA really that important, or is it just a tool for determining what mash pH will be?