last time i was in the LHBS i asked the same question... i was picking up a few batches worth and had planned to keep one of the bags sealed up for a while. they told me to put it in an air tight container and it would be fine for 2-3 months. i do not know the validity behind that answer...
i used up my second batch after 4 weeks of storage without any issues.
That was more of an answer than I have gotten from anyone else so thanks. I would think that it would last a while as long as it is in an air tight container. I was hopping to maybe stock up for a couple of recipes. Thanks for the input!
I had a 5 month hiatus from brewing. Two weekends ago brewed up a batch with 2row from a bag of crushed grain i bought about 8-9 moths ago and it was fine. no difference in efficiency or taste. was kept in plastic that was put in an airtight bucket. the grain was still nice and crisp too.