How long is crushed grain good for?

I bought and crushed about 18lbs of grain for a 10 gallon batch around the middle of may. It's been sitting in one of those bulk grain bags rubber banded at the top in my basement since then. I'm pretty sure the grain is probably on the stale side now but I'm not sure how long that type of thing takes.

 

It'll be somewhat less "bright" in terms of aroma qualities and the diastatic power may have dropped. I generally recommend to people that they should use their grains within three weeks of crushing for best results, unless they freeze them in moisture-barrier bags. That said, I have brewed a partial mash beer with grains that had been sitting crushed at room temperature for two months, and it still made a decent beer.

What type of beer is it? If it's heavy on roast, I'd say go for it. If it's light in malt character, ditto. If it's a malt-forward beer that depends on a complex balance of malt character, I'd say buy new grain.

 

It was bier munchers centennial blonde ale. I wanted to stock up on some
Full kegs of a bunch of different styles including his blonde, before my son was born in June . Problem was he came a little early in the third week of may so I never got to brewing the blonde. Been super busy since then with little man.

 

If they are sealed in plastic bags I would bet the grain is just fine.

 

Not sealed just wrapped in one of those bulk grain bags

 

Still good. I wouldn't probably use it if it was sitting open in a dark, damp basement all summer though.

 

I'm in a similar boat. Bought enough grain for 4 batches over a month ago when Austin Homebrew had a free shipping deal or something like that. Expected to be able to bang them out pretty quickly, but my brewing partner is obviously not as interested in brewing as he once was (now that he has a kid).
Anyway, my apartment wouldn't work to brew as I don't have a place with enough temperature control. When I move into my new apartment next week, I'll buy some new gear and use up the rest of the grain. By then, it will have been about 2 months, though the majority of the grain has stayed sealed in the plastic bags inside the box it came in. Some of the 2 row got used up when we were able to find time to brew one of the batches (a SMaSH IPA), so that one bag had been opened and is now sitting in its bag inside the empty brew kettle with the lid on.
These beers may not turn out quite as good, but I'm still going to use it all up!