[James Lorden]

I agree that the main goal of mash temp is fermentability. That being said, I noticed a bump in my efficiency when I started doing mash outs. I have heard it rationalized that the higher temps dissolve the sugar better allowing the water to do a better job of carrying it to the brew pot.  although this explanation makes sense to me, I can't say that it's fact, just my experience.

[denny]

I agree that the main goal of mash temp is fermentability. That being said, I noticed a bump in my efficiency when I started doing mash outs. I have heard it rationalized that the higher temps dissolve the sugar better allowing the water to do a better job of carrying it to the brew pot.  although this explanation makes sense to me, I can't say that it's fact, just my experience.

Kai Troester has disproven that, at least to my satisfaction.  I think that  the reason is that you get more complete conversion by raising the temp.