« on: September 02, 2011, 01:10:10 PM »
I use anywhere from 6-12% Carafa Special II in my Black IPAs and I add them at sparge (and I sparge cooler than usual). You still get a noticeable roast character. Oreo cookie is how I describe it. The only time anyone mentioned it being too roasty was when I used the smallest amount, actually (I think they found the beer too minerally and believed that came from the roast, not the water). I would treat the mash water as you would for a pale ale and the sparge water should just remail soft (add some extra sulfate in the boil if you must). I think getting the water right is a big part of nailing this style. If you mash with the dark grains, then you will need a suitable water profile for a proper mash and your final beer will taste like a hoppy porter. If you keep the water more APA/IPA-appropriate, but still manage to use the dark malts without a pH issue, your resulting beer will be more IPA-like
I agree that high carbonate water could lead to a very roasty, astringent flavor in CDAs. I generally dilute my tap water with 50-60% R/O water and adjust back with sulfate in the kettle when doing hoppy ales. I also try to keep my sparge water pH around 6 for all beers.
Citra hops would work fine in a CDA as their citrus quality will play off well with the dank CTZ flavor.