Letting Crushed Grains Sit

Ok,

So I'm not looking for a why don't you just crush them yourself or go to the brewshop the day before the brew, I just have a question.

If I purchased my grains today and get them crushed at the shop, will it really effect the beer that I make if I don't brew until Saturday???

I've heard that it will but I'm wondering what kind of difference 4 days will make for a bag of crushed grains.

What specifically will be effected??

No, a few days doesn't really matter. Taste the grains- they should still be fresh tasting. It's storing them for longer periods of time that is a problem. Uncrushed, they last a long time. Once they are crushed, though, they go stale fairly quickly. I'd use them within a couple of weeks. If you keep them in a plastic bag, sealed, in a cool dry place they'd last longer.

I wouldn't worry if it is less than a month, if you keep it cool & dry. When I buy multiple for batches, I freeze the extras.

I buy my grains online and have them shipped and I try to time it so they get to my house within 3 days but the last batch I timed wrong and they shipped out on Thursday which meant they were in a UPS warehouse all weekend but still it makes little difference. I've kept crushed grains for as long as 2 weeks before brewing and I'm sure longer would be OK. If I had a crusher I would crush right before brewing but I don't so, waddya gonna do?