There are several things you should look for when purchasing frozen lobster.
Ask the seller if the lobster tails were soaked in sodium tripoyphosphate prior to freezing. If they have, you don’t want to buy them.
Another important factor to look out for is what is termed “glazing.” This is something that is typically only done to warm water lobster tails and is done to protect them during storage. It is a process in which water is injected into the lobster between the meat and the shell before freezing. While it may help protect the lobster during storage, it also increases the total weight by as much as 20%. Since the extra water will cook off, you are essentially receiving 20% less lobster for the price you pay by weight.