I have been looking at brewing several recipes that call for a multi-step mash that includes a protein rest. I saw a Mr Wizard article in BYO that sort of defends protein rests.
Just like the questioner in that article, I thought that protein rests were unnecessary for well-modified malts, but Mr Wizard says that brewers still consider a protein rest necessary where there is 20% of more wheat in the grain bill (for clarity purposes, I guess), or to ease separate of wort in the lauter.
This doesn't make sense to me, because it seems that any proteolytic enzymes in the malted wheat (and other malts) would have been destroyed by the malting process, meaning that no protein is being affected by the protein rest. Is it correct that there are no or negligible amounts of proteolytic enzymes in modern malted grains?
Also, as far as separating wort, wouldn't a mash-out step or high-temp sparge do the same, if you bring the mash up to 170°F?