Scallops are the shell-fish whose shells look like the logo for Shell oil. They need anywhere from 18 months to 2 years to grow to market size. They can live up to 20 years old, but those are too tough to eat.
Scallops don't burrow into the sand, like many other shellfish do. Instead, they just live on the bottom, and use their "adductor" muscles to push out jets of water which move them around.
Scallops are generally sold already shucked -- with the nuggets of flesh that we eat and also refer to as "Scallops" removed from the Scallop's shell. Those nuggets of flesh that we eat are actually the "adductor" muscles. In the trade, these parts are referred to as the "meat." In theory, all the Scallop is edible, but it is generally advised to eat only the "meats", as toxins may accumulate in other parts of the Scallop.
Sometimes, there are actually two parts to the flesh nuggets you buy, if they are sold with a red. crescent-shaped part of the inside flesh still attached. This is called the "coral" by some, and the "roe" by others. The roe has a bright orange coral colour. You will usually only get it when you buy fresh, whole Scallops. Many people feel that, possible toxin concerns aside, the Scallops just aren't as good without this. The coral has a slightly bitter taste, which helps to cut through the richness of the rest of the Scallop. You are more likely to come across Scallop meats with the coral attached in the UK than you are in North America.
At grocery stores, you may see Sea Scallop meats labelled as jumbo, large or medium, but they are also sold based on how many it takes to make up a pound (450g.) 10 - 20 would be the jumbo ones; 30 - 40 would be the medium ones. To make up a pound of Bay Scallops, 70 to 80 meats are required. Allow 2 to 3 Sea Scallops per person; about double that for Bay Scallops.
Sea Scallops (Placopecten magellanicus)Sea Scallops are larger than Bay Scallops. Their shells can be up to 8 inches (20 cm) wide. The adductor muscles can be up to 2 inches (5 cm) wide and each weigh, after shelling, up to 1 1/2 oz (40g.) They are fished for throughout the year. They won't survive very long out of the water, so they are usually shucked and chilled right on the boat, before being taken back to the mainland for packaging and freezing.
Bay Scallops (aka Argopecten irradians)Their shells can be up to 3 inches (7.5 cm) wide. They live in the sea, too, but along the coast of more northerly areas such as Japan, China or New England (they are not native to Asia, but have been introduced there for sea-farming purposes.) Many people consider Bay Scallops sweeter than Sea Scallops.
Calico Scallops (aka Argopecten gibbus)Calico Scallops live generally on shorelines of the Caribbean: off the Southern US, Mexico, and northern South America. They are the very small Scallops with the wonderfully decorative shells that we liked gathering as kids. As they are so small and fiddly to shuck, and hard to open, they are generally steamed first to persuade them to open. The meats are a little tougher than Bay or Sea Scallops, so they are considered the least desirable type of Scallop to eat.
Alaskan ScallopsAlaskan Scallops are about the size of Sea Scallops, but with a milder taste.
Wet Pack Scallops (Soaked Scallops)Most Scallops used to be treated by soaking them in water with phosphates to stop them from losing water and shrinking. The more water in them, the more they weigh, and the more they are worth. The processing industry went a little crazy on the phosphates (which were safe to consume, by the way), and starting using more of them, which caused the Scallops to not only not lose water, but to take up additional water and increase their weight up to 25%, so the consumer was paying for more water. The American Food and Drug Administration cottoned onto this and established guidelines in the 1990s: if the water content of the Scallops went over 80%, the natural water content of Scallops, the Scallops would have to be labelled "Scallop product -- water added."
Phosphates can still be used to help the Scallops retain the water, but as many producers don't want the ignominy of having their Scallops labelled "Scallop product", which would command a lower price, this regulation discourages the excessive use of water to turn the Scallops into sponges.
Wet Pack Scallops will look very white. The problem with these is that, while they look very nice, their weight has been artificially increased (which you pay for), and they tend to boil or steam (and consequently shrink) when fried or barbequed, rather than having their exterior get nice and crusty.
Dry Pack Scallops (Unsoaked Scallops)"Dry Pack" or "Unsoaked" Scallops are Scallops that have not been treated with any phosphates at all -- some cooks believe that phosphates cause the taste to deteriorate. A bit more moisture will seep out of these during cooking. Dry Pack Scallops will be darker, and a bit sticky to handle.
Diver-Caught ScallopsAnd in case you think you've now got it all figured out, the price of Scallops will vary depending on whether they have been caught by dredgers, or divers. The dredged ones are cheaper, but can taste "muddy." Diver-caught ones are considered better, and so are the more expensive of the two. Most Scallops are, however, dredged.
Your local grocery stores may not offer you any choice in what you get, but at least now you have an idea of what you're buying.
Choose Scallops with no fishy smell. If they are very white, chances are they have been treated with a lot of phosphate. More natural colours are ivory or light tan. Sometimes, Scallops may have a slightly orangey or pinky colour owing to the algae they eat, but that is fine.
To prepare Scallops still in their shell, scrub the shells well. Holding the shell curved side up in one hand, insert the tip of a knife on one side of its hinge at the back and work it round to the other side. (You don't need a really pointy, sharp knife: duller-bladed ones are safer, and in fact, purpose-made Scallop knives are dull-bladed.) Lift off and discard the top shell. Inside the Scallop, discard black stomach bag and the brownish frill around the centre meat. Americans prefer to discard the coral as well, while Brits and Australians think they are mad to do this. Rinse to remove any sand. Slide the knife under the meat and coral to detach them from the shell. There will still be a small, hard piece of ligament left on the side; pull this off and discard it. Cook the prepared Scallops according to your recipe.
1 pound Sea Scallops = 450g = 30 Scallops = 2 cups
Literature & Lore
St James the Apostle is supposed to have intervened and saved the life of a drowning crusader knight, who came out of the sea covered in Scallop shells. An order of knights was named consequently named in St James's honour, as was the Scallop dish "Coquilles St. Jacques".
The cooking technique called "to scallop" is unrelated to the word "Scallop" (the See Also link to "scallop" below will give more information on how the word did come about.)
In Japanese, "kaibashira" are large Scallops; "kobashiri" are small Scallops.
Note that some confusion exists as to whether the muscle inside the Scallop is called the "abductor" muscle or the "adductor" muscle. It is in fact the "adductor".
ScallopsDried Scallops; King Scallops; Queen Scallops (Australia); Queen Scallops (New Zealand); Queen Scallops (UK); Scallops
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