Used Bru'n Water to formulate my mash/kettle additions for an American Amber yesterday. Here are my observations...
Based on the grain bill I plugged into the calculator, Bru'n Water calculated that I needed to add .8g NaHCO3 to hit a mash pH of 5.3 At the end of my 60 minute mash, I tested the pH using a colorpHast strip. The strip read 5.1-5.2. Assuming that colorpHast strips read a little low (between .1-.3, from what I've been able to gather from others' experiences), then my pH was pretty much within the desired range (but only if I accept that my colorpHast strips read low).
My mash conversion was excellent. I hit my target O.G. (1.056) and brewhouse efficiency.
I added 2g CaCO3, .7g CaCl, and 4.5 MgSO4 to the kettle (pre-boil) to create the following profile: 55 Ca, 21 Mg, 18 Na, 41 Cl, 93 SO4, 77 CaCO3. After chilling my wort, I had phenomenal cold break. Honestly, it may have been the most I've ever seen in my fermenter.
So, my initial impression is that I like how this calculator takes specific grain bills into account because it seems to make a difference. Using a Palmer-style RA calculation based solely on SRM, I would have had to add considerably more mash salts to hit my target pH. Over the past few weeks, I've been a little skeptical of some of these new water chemistry calculators (see this thread
). Having observed some impressive results using Bru'n Water, I think the subject is worth exploring further.