Originally Posted by Kaiser
Using reverse osmosis water might be cheaper than DI water and effectively the same for brewing. I only buy DI water for experiments and rinsing the pH meter probe but brew with RO water +salts.
I still like calcium carbonate for adding alkalinity to the water even though it seems about half as effective as it should be if its not dissolved with CO2. I have used it both ways and didn't find a difference (except for using twice as much) that would warrant telling brewers to dissolve their CaCO3 or use slaked lime instead.
sodium bicarbonate (baking soda) is also very effective, but you have to watch the sodium level of the resulting water. If you start with R/O water that should not be that difficult.
Thanks for the info, Kai. I ended up brewing the Pils last night using spring water I already had on hand so I'll have to try my hand using RO/DI water another time.
Btw, your posts here and over on your wiki have really helped me out as I've started venturing into brewing German beers (altbier, kolsch, and this Pils). Thanks for providing all that info.
Fwiw, here's the estimated water and mash profile I ended up with for my Pils (which was 98% pilsener malt, 2% acidulated malt):
Water mineral estimates (all ppm):
Alkalinity: 20 (as CaCO3)
protein rest @ 131°F for 20 minutes
sacch rest @ 148°F for 45 minutes
thin decoction (10 min boil) to mash out @ 170°F