Choose broccoli heads with tight, green florets and firm stalks. The broccoli should feel heavy for its size. The cut ends of the stalks should be fresh and moist looking. Avoid broccoli with dried out or browning stem ends or yellowing florets. Store broccoli unwashed in an open plastic bag in the refrigerator. If bought very fresh (i.e. at a farmers market) broccoli will keep up to 10 days.