Mylo wrote:In the grand scheme of things, we are talking about steeping grains here. If tannin extraction is time, temperature, and pH related - then we are splitting hairs here. Not only is the percentage of steeping grains very small relative to your extract - but the time is only 30 min, and the temp is 150 instead of 170. Could your beer have more tannins? Perhaps. Will it be noticible? Probably not. It's much more of a concern when you go to all grain.
The same holds true for the "add the bag cold" vs. "add the bag at temp" decision. Will the longer contact time with the "higher than optimum" pH of the water extract more tannins? Yes, perhaps. Will it be noticible? Probably not. Ideally, to minimize tannin extraction - your steep would be in 5.2 - 5.4 pH range. Using a tighter grist/water ratio will help with that, as the acidic, darker steeping grain will lower it. You can also add a little gypsum, too. All beer has tannins. You just need to stay below the flavor threshold, which shouldn't be a problem with a small amount of steeping grains.
Although he lists the options in his book, I think JZ mentioned in more than a couple of his shows that, in his opinion, both cold water steeping of very dark grains and chemically adjusting your water to correct for pH, hardness, etc aren't really worth it in the vast majority of cases for the same basic reasons you describe.