I read in Palmers first edition of how to brew, that boiling malt releases sulfur, and that's why we keep the lid off during the boil, to let it escape. However given that most people seem to do late additions, I imagine that isn't that much of a factor or maybe only an issue with certain kinds of malt. Plus palmer has changed his mind on other topics, so....I'm no expert as I've just done pre-hopped beer kits.
I will add that on another thread I was told by Yooper that you don't need malt present at all during the boil for hop isomerization, and that many add some malt to make the process closer to the grain method. I'm planning on doing that as an experiment and seeing if I notice a difference, since once you add the malt, boil overs are a huge risk.
I will add that on another thread I was told by Yooper that you don't need malt present at all during the boil for hop isomerization, and that many add some malt to make the process closer to the grain method. I'm planning on doing that as an experiment and seeing if I notice a difference, since once you add the malt, boil overs are a huge risk.