Originally Posted by Jakemo
I add most of my LME at the end of boil. I thought I read somewhere that DME needs to be boiled.... any merit to this claim?
DME goes through a hot break if you boil it, where it breaks down the complex proteins into more basic amino acids, among other chemical processes I can't speak intelligibly about. Among other things, this gives you a clearer finished product. I've also read oxidation is a greater risk if you don't let DME go through a hot break. Not to say boiling the DME is necessary, but it is recommended in all literature I've read.
With the hot break, be vigilant not to let it become too violent and boil over. A boil over during the hot break can be prevented by removing the wort from heat repeatedly until foaming subsides, keeping the temperature just below boiling until the wort changes from a cloudy color to a dark, clearer color, and/or stirring the foam back into the wort.