After reading Chris Colby's article in Nov/Dec Zymurgy,I think i'll give this a try brewing a RIS. Was wondering if I should do my first mash all base malt, then add specialty malts in the second mash. And should i add more (brewing salts) to the second mash?
Any other tips or comments are welcome. Or, if another thread has been started pls. redirect me, thanks.
The only iterated mash I've done was 100% base malt (a 100% MO barleywine), so I have no experience with the specialty malt question. Whatever choice you make, just be sure that your initial mash pH will fall in an acceptable range with whatever malts you use in that iteration. In other words, if you're counting on your specialty grains to help lower your pH into your target range, then plan on including them in your initial mash.
As far as adding additional salts for the second mash, I don't think you will need to. I don't think adding more malt to a mash will be likely to increase the pH. If anything, it could potentially drop the pH a bit more.
Personally, I think I'd be inclined to add my specialty grains in the initial mash for simplicity's sake in estimating my initial pH.