Treating water for fun

I've gotten to the point when I'm looking for a new challenge in brewing and I think water is the next frontier. I understand the science, and the reasons, and what each type of mineral contributes. My real question is: why?

I like my beers so far, but I've been using John Palmer's Residual Alkalinity spreadsheet, and I realize that my darker beers need a lot more RA in the mash water. That's fine, I can bump that up with chalk or baking soda. But then I start looking at the other minerals, and I'm thinking, "Well, I guess I could bump these up to the accepted levels, but I'm not really sure what that will accomplish."

Lucky for me I live in an area with a pretty low mineral content, so I don't really need to do any diluting. If I make no water adjustments, Palmer tells me I should be making beers with an SRM of about 5-10. But when it comes to making stouts, I start to wonder about all the calcium or sodium I'm contributing when I add salts to up the RA. Here's my water report:

Ca - 16
Mg - 10
HCO3 - 15
Na - 5
Cl - 5
SO4 - 18

I make a house brown ale a lot with a target SRM of 22. To get the RA where I need it, I can add 18g of chalk but this increases my Ca to 367ppm. That's probably a little high. Alternatively I can add 6g of baking soda, but this increases my sodium to 85ppm. Ultimately, I should probably add a mix of the two, first choosing how much calcium I want in the final beer, and then making up the rest with baking soda, but I'm having trouble understanding how I really choose the right level of calcium.

The same stuff applies with the Cl:SO4 ratio. My actual ratio says that my water is geared towards very bitter beers, but I find it hard to believe that such low levels of Cl and SO4 really have the impact that the ratio suggests. So let's say I want to keep the ratio the same - I'm still having trouble deciding how much of each mineral to add. I mean, 50Cl with 150SO4 is the same ratio as 200Cl and 600SO4, and apparently all these levels are "acceptable" in beer.

I guess the last thing that's bugging me is the experimentation. I could just start doing experiments here, but this isn't like the difference in four ounces of dry hops or none. I wonder if these water adjustments are so subtle that I'll never really tell the difference. As I said, I already like my beers.

Any insight here?

http://braukaiser.com/wiki/index.php/Beer_color,_alkalinity_and_mash_pH

Check that out. SRM and acidity have a very tenuous relationship, at best. Using SRM to estimate needed RA is essentially useless.

Read any posts by ajdelange on this site. AJ DeLange is a better brewer and scientist than I may ever be, and he recommends never adding any alkalinity, except when you mash in and your mash is actually too acidic. He also says that pH strips are biased -.3 pH, so if you read a 4.9 with strips, you're actually at 5.2.

http://www.themadfermentationist.com/2008/09/i-think-that-water-treatment-has-made.html

If you haven't read it, a quick and dirty guide to water treatment.

Thanks. I had read Kai's article and had come to similar conclusions about the relationship between SRM and RA. However, I'll point once again to my source water's low mineral content, which suggests that I maybe need to boost the RA when brewing average colored beers, and certainly need to when brewing darker.

The second article is exactly what I'm looking for so thanks a bunch for that.

Those tests were all done with distilled water, so 0 mineral content. Even with very dark malts and no minerals, only like 4 of the tests out of 200+ were slightly below the ideal range.

So I would say you almost never have to add alkalinity to any beer ever, unless you actually test the pH of the mash after dough-in.