temperature of stock water

[Tomas]

I have always been told by my chefs to only use cold water when making stocks. I then read in Patricia Well's AT HOME IN PROVENCE, that the only reason chefs used cold water was because in those days the water contained more lead. Is this the only reason we use cold water?

[Michael Ruhlman]

I hadn't read that about the lead--and she may well be right. Can you make stock by starting with hot water, sure. But why would you need to start with hot. If you're really crunched for time, that may be necessary, but if you're crunched for time and just starting your stock you've probably got bigger problems to worry about. I believe that starting with cold stock is better because it allows you to get rid of more of the impurities and scum early in the stock making process. I believe that the slow rise in temperature is more effective because of that. Certainly if you're blanching beef or veal bones, the slow rise in temp gets more blood and crap out of the bones for a cleaner stock. My personal observation and practice.