How long can milled grain be stored?

Question

At the rate that I'm going, I'm doing a homebrew roughly every second weekend. (Fun!) I will end up with a small stock of hops, and yeast I can keep around in the fridge for a while if I buy a few extra vials, but I'm wondering about milled grains?

I don't have the space or inclination to mill myself. If I want to pick up 5-10 pounds of base grains and a small stock of specialty grains, and have them milled by my LHBS at time of purchase, how long can I expect them to stay fresh in a bugproof container in a cool, dark, dry corner of a closet?

I found this question about grain storage, but the asker's express intent is to take it to his LHBS and mill on brewday.

Does milled grain have a shorter shelf-life than unmilled?

Answer 1

Milled grain does have a shorter shelf-life, but you don't need to worry about it unless you are trying to mill more than a month in advance. I used to get my grain milled and shipped to me and I would use it when I got around to doing a brew. I never noticed major taste differences within about a month of being milled, and I was just using cardboard boxes and plastic supermarket bags. Much more than a month and I generally went for a higher hop content as opposed to trying to store the grain better.

You do need to worry about moisture. The more moisture that surrounds your malt (no matter what state milled or not), the more the flavours and aromas fade. You also run the risk of growing moulds. Generally moulds like temperatures between 40 and 70 F and high humidities. In terms of buildings and mould, the EPA recommends reducing humidities to below 60% and the CDC recommends humidities no higher than 50%.

In other words, if you can keep your grain cold and dry, then you should be able to keep milled grain for a few months without noticing major changes in taste.