I knew a chef who use to use Evian bottled water for his fish stocks. Or at least that's what he told reporters. Every one thaught he's crazy. Still in hebrew as stock is called "axis" and that's what they are in french influenced cooking, so doesn't it deserve the best ingredients including water. Then I started noticing the bottoma of bain marries. Do an experiment in your own kitchen, take some water and reduce by half, or third. YUCK. That's what i got to say. Yuck. Tap water's bad enough but when consentraded? Yuck. When we make stocks isn't that's exactly what we do, we concentrate all thae trash in the water. I doh't know. What I do know is that now I noticed how many stocks do taste "stony" to me. Maybe I am wrong, after all we do descum the stock, and maybe the vegetables and bones take more impurities out. And beside, bottled water's high mineral content wouldn't make the best replacment will it?! Maybe yes. I don't know. So what do you think. Tap water, purified water, bottled?