I am currently deployed and will be back home in about a month and a half. I want to start brewing and I was going to start with some extract kits from midwest. If I get a kit with specialty grains, do they need to be crushed, if so, how long will crushed grains keep before they need to be brewed? Thanks for your help. I'm trying to plan when to make my purchase so everything will be at home and ready for when I get back.