[donosborn]

Well, I do have picky standards, and I often collect the wort before going to bed, and get up and boil in the morning. This is a great way to cut down on the "time away from family stuff" (especially on the weekends) that a brew day requires.

Even if you do not heat up the wort, the temp will be 160-170 at night, and still around 130 in the morning.  That is still very hot, and I doubt anything bad can survive in that temp.   (and you are still going to boil anyway).  Sure you could heat it up even hotter, and thus it would be even warmer in the am.

But no, there is no reason you can not do this.  I can't tell any difference in beers made this way vs doing it all in one day.  And for the record I have been brewing for nearly 10 years and have taken gold medals in a few competitions. 
cheers
don

[redzim]

I've done a two-day process for at least a year now (20+ 10-gal & 15-gal) batches. 

Day 1: mill grains, mash in 80qt Coleman Extreme, batch sparge, put liquid in brute barrel in walk-in cooler
Day 2: dump wort in kettle, brew, chill, pitch yeast

Total time each day of about 3 hrs. I usually do each step in the morning, so there is about 20hours between when the brute barrel goes into the cooler and when it is boiling the next day.  I have never noticed any problems; and a Maibock I brewed with this process just took a second place in the New York State Fair; and a Helles took a first place in the same comp.

-red