Residual alkalinity question

[rockymtnbrewer]

I'm relatively new to creating my own recipes and altering water. My plan is to make a brown ale somewhere between a NE and American.

Eldorado Springs water(100%):
Calcium 11.4
Magnesium 3.4
Sodium 6.2
Chloride .97
Sulfate 20
Bicarbonate 35.5

Water additions
2 g. Gypsum
5 g. Calcium chloride

Grains
9 lbs. Pale (3.5L)
1 lb. Brown (65L)
.5 lb. Crystal (120L)
.25 lb. Roasted barley (300L)

I used brewersfriend's advanced water calculator and get a mash pH around 5.4. My question regarding residual alkalinity, it gives me -21.
I have read this low RA would be better suited to make a lighter colored beer. I have also read not to worry about RA and only check pH. Which advice do I follow?

 

[mabrungard]

RA is not a targeted value. The only thing that matters is pH. Ignore RA.

 

[ajdelange]

RA (the proton deficit of the water adjusted for the protons released by the malt phosphorous-phytin reaction at knockout) was conceived back in 1941 as a means of comparing brewing waters in a country which forbade adjustment of mash pH by the addition of external acids. While most people think of Kolbachs paper as a vehicle for re-introducing and defining RA it is actually an appeal to brewers to pressure the government to allow the addition of external acids.

The RA for your water is fairly close to 0. What that tells you is that you don't have to do much to it to make it behave like distilled water.

A few years back home brewers got the idea that RA could be extended to include the effects of acids or bases added to the water and then to the mash. While technically you can do that it lead to confusion as it was often not clear which parts of the mash proton balance budget were included in RA and which weren't. As we came to appreciate the details of mash acid/base chemistry better RA has fallen out of favor as a design parameter. If you manipulate the proton budget to achieve mash pH of 5.4 you have reached your goal and it doesn't matter what the RA is no matter how you define it so follow the latter path and ignore it.