Which lucky crustacean to pluck from the tank? Many swear by the meat of the females, and we agree. You want to use lady lobsters in soups or stews--their roe will intensify the flavor.
There are two easy ways to tell the difference between the guys and gals. First, flip those suckers over and take a look at the set of grabbers (note: not the scientific term) below the legs and smack in-between the tail and the torso. If they are thin and feathery as opposed to thick and bony, you've got yourself a lady. If you are dealing with a modest crustacean who won't let you take a peek, you may be able to tell by the width of the tail. Females tend to have wider tails that skirt out at the bottom to accommodate eggs/future lobster rolls.
Gender aside, make sure to scan the tank for a vivacious lobster; the more active the lobster, the more tender the meat. The length of the antennae is another indicator; longer is better.
Use these simple guidelines and venture to the market without fear. You'll never have to suffer through another tough lobster roll again.
Source: http://www.bonappetit.com
