Buying shellfish is a lot of fun. If you intend to buy shellfish then mollusks such as mussels, clams, oysters and scallops should be checked out carefully. Always eat clams, oysters and mussels as soon as you can. Time in the refrigerator should be 24 hours max, put in a plastic bag and put holes in it to allow air to circulate. Like all forays into a fish market, treat all shellfish with caution, as guarantee of freshness is never assured. The information below gives you the common ways of checking mollusks for freshness and quality.
Oysters
are my favorite shellfish and there are tricks to buying them, and given they
are no longer cheap then follow this advice. They like all seafood should have
that fresh ocean and sea smell. They should feel heavy for their size, which is
an indication they have juicy internals along with those natural liquor or
juices. Handpick your own. If they are gaping open shells or have a hollow sound
when tapped then avoid. Ask and pay for a sample just to be sure. If in Western
countries they may have a bag tag showing harvest date. Also check they are alive, if a shell is
partially cracked open, tap the shell and it should close, means the inhabitant
is alive and dead of the shell stays open.
Scallops have that lovely off-white color to light pink or orange. They should also have a pleasant briny sea smell and no odors. Also perform the shell tap test for ones that are open. Fresh out of the water scallops can be eaten like sashimi, well worth trying. They have that sweet, delicate and buttery flavor that is so delicious. Fresh raw scallop meat should be translucent and have a slightly sticky feel that indicates it has not been frozen or stored in water.
Same rules again here, they must be alive, must smell briny and fresh. Clams should be tightly closed, any that are open, tap the neck and they should close up. If the clam shells don’t close then discard them, also don’t use ones with cracked or shipped shells. There are many varieties and the Atlantic hard shell clams are known as quahogs. The large clams are tougher and used in chowders and medium quahogs are called cherrystones with the smallest known as littlenecks. In some places you can buy razor clams, which I really like. In the Pacific you get Manila clams and in Australia a similar thing called a Pippi is delicious.
Always select mussels that are alive and proven alive. Choose mussels that have firmly closed shells. Some mussels might be slightly open, that doesn’t mean they are dead. To check for signs of life simply tap the shell and if it closes the shell it is alive, and if it doesn’t then don’t use it. Mussels should have shiny and damp shell and have that good briny ocean and sea smell, not too fishy. Pick up the mussels and check the weight. If they appear very light or very heavy don’t select them.
Fresh caught Squid, Calimari and Cuttlefish generally has a white, elastic, quite firm and slightly translucent flesh with a mottled brown skin. The skin should be smooth, shiny and intact with patches of that iridescence. If you are able to then place some fingers inside the tube and you should be able to see them. The squid should look plump and not deflated. Smell them for that clean, briny and ocean scent. The hood of the squid is covered with that familiar purple to gray membrane that is actually edible, although many remove it.
If there is some opacity and discoloration then they are not as fresh as they could be. Less than fresh you will note a darkening of the flesh with a fairly strong pink tinge to it. Older squid and cuttlefish can experience skin damage of trawled rather than jig caught. Old squid may also tend to show damaged and broken arms or tentacles. It may show a loss of flesh elasticity. If you see ink on the fish that does not mean it’s not good, but if you buy wash in saltwater as it can promote bacterial growth. I fell in love with Calimari in the Greek Islands and just love cooking those smaller ones. Olive oil, garlic, lemon juice and its done. Cook it fast within a couple of minutes or cook slow, anything in between is rubbery.
These members of the cephalopod family are one of my favorites. I love eating octopus, Spain, Greece and Portugal are great places to eat. Choose octopus that have a double or two rows of tentacle suckers as this evidently denotes better quality and flavor, although I am a big fan of baby octopus (Octopus aegina). Freshness is all in the eyes, check out the eyes are bright and clean. They should have an intact and bright skin, also the tentacles should be intact. They should smell nice and briny with that familiar ocean smell. If the seller is able to then have them remove the beak, sac, viscera and eyes.
Many say you should put the octopus in a freezer overnight to improve tenderness when cooking and that is what I do. The freezing process breaks down the flesh fibers and making it more tender. Grilled or pan fried or on the BBQ they are delicious. reputation for toughness is a bit over stated. About preparation, Greeks often beat it against rocks to soften it up. A Spaniard might dip it into boiling water three times and then cook only in a copper pot. An Italian cook might cook it with two corks in the pot. The Japanese often rub it all over in salt. The secret is in long slow cooking. Buying shellfish is fun and also the secret to how to cook with seafood.