Yes, it matters. Here's a link to get you started.
http://www.inthewoodshop.org/methods/wwc01.shtml
--dave

wrote in message
oups.com...
I am buying alot of quartersawn white oak in the rough and I had a
question. I need to mill it in my Delta 12" planner but since both the
top and bottom are rough is there a proper way to ensure I have a flat
board when I finish milling it. The lumber does not have a smooth
surface on the bottom when I first put it into the planer but I want to
make sure that it remains flat as I mill it so when it it flipped over
to do the other side the board is flat or does it matter.
Thanks,
Mike