For you oyster pros out there...do they have to open when they are cooked? Some say yes, some no... I picked up a dozen to grill for Valentine's day. Six did not open...at $1/pop I am kind of disappointed. The taste was great, especially the liquor. I served them with horseradish whipped cream. I grilled oysters before but never tossed more than 2 out of a dozen. Two weeks ago also bought 5lbs of high oxygen packed mussels (Costco). Usually very few are bad. But this time I trashed about 1/3. The very cold weather maybe?