General RA guidelines for darker beers.

[Rivenin]

So, diving more into the depths of water salts and mineral additions. I'm starting to look more into RA and darker beers. I'm brewing a brown weekend after next, so i'm starting to look at doing the water profile.
Is there a general rule of thumb for what to "Shoot for" regarding RA and SRM?

The recipe is from the brewery of the beer and It's for a nut brown

10gal 82% eff

15.5 2 row
8oz flaked barley
8oz crystal 120l
8oz crystal 5
8oz munich malt
4.8oz chocolate 500l
4.8oz roasted 600l

18srm
5.6 sparge
8.85 sparge

my water profile is

CA 6
SO4 8
MG 2
NA 8
Cl 6.5
alkalinity 26

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However, not ever playing with RA before and the need for baking soda. I'm not completely sure what i'd be looking at here for proper salts for PH and RA adjustment if i'm not sure what the RA needs to be for darker beers for SRM. Googling didn't lead me to much unfortunately.

Any help would be lovely!

 

[motosapiens]

i'll be interested to see the responses from smart people. I also am just learning about water.

what I do is acidify my sparge water to get under 25 (using bru'n-water spreadsheet), and then add whatever gypsum and chloride I want for flavor, and whatever acid i need (usually none with porters/stouts) to get an appropriate predicted mash ph. Seems to be getting me in the ballpark while i'm learning, but the alkalinity of my tapwater is 170-ish.

 

[McKnuckle]

You will find posts about this, but they tend to be buried in the noise. In short, you don't actually target residual alkalinity as a goal in itself. You aim for an appropriate mash pH. RA then takes care of itself as part of the equation. Mash pH for darker beers is usually best on the higher side of the range, 5.5 will do it (at room temperature).

One way to approach a dark beer's water profile is to take a minimalist approach toward mineral additions. First, add CaCl until Calcium is around 40 ppm. Chloride will then also be at around the same level. Gypsum (for sulfate) is not required at all, neither is Mg. Once you have hit the 40 ppm Ca level, look at the predicted mash pH. It is certain to be below 5.5, probably by a decent amount. Now, add just enough baking soda to raise it to 5.5. You should end up with no more than 20 ppm sodium (Na) in the mash.

A nut brown ale at 18 SRM is not too dark, really. You can do fine with mash pH of 5.45 also. It's hard to give a prescription for this because there is no such thing. Brew it and try it!

 

[Rivenin]

Awesome, thank you!
I've heard so many different stories on this that it's just been odd. But i will try that out!

 

[McKnuckle]

I think you hear many stories because lots of brewers drink the KoolAid that suggests for us to match a historical water profile with our beer. I think that approach was introduced to give people some examples based on (questionable) reality, and it gives us a feeling that we are choosing something "legit."

Another perspective we see a lot of is the highly scientific one, where the author mentions moles, anions, cations, and exotic units of measure. Great stuff - but it's too deep in the weeds for most of us.

In reality, I've found that a minimal approach that ensures a good pH but doesn't exceed any thresholds with regard to mineral levels is a great starting point. From there, if you want to find out what 200 ppm SO4 does to your IPA, go for it. But it's always safe to aim for Ca of 40-50 using CaCl and/or gypsum. Cl and SO4 will be at nominal levels using that approach. From there, if you still have to get a lower pH, use lactic acid... higher pH, baking soda. (All of this assumes that you're using RO/DI as a blank slate.)