What's the difference between dry and wet scallops. I think dry are preferable, but why?
You are correct! Dry scallops are not treated with chemicals like "wet" scallops are.
Dry scallops haven't been treated/preserved with any chemicals and are what you need to use if you want to get a nice sear on the scallop. Wet scallops have been treated with sodium tripolyphosphate to "preserve freshness" and retain water. Even if you pat these dry, they will weep water when cooked and won't get a good sear on them.
all of the above are correct. Dry scallops won't shrink to nothing when seared.
Wet scallops are treated with a chemical - sodium tripolyphosphate - which helps improve shelf-life but really negatively impacts the flavor. Ideally find dry scallops. If you cannot find dry scallops, CI recommends soaking the wet scallops in a solution of 1 qt water, 1/4 cup lemon juice, and 2 T salt for 30 minutes. The acid counteracts the alkaline sodium tripolyphosphate. When you season them for cooking after their soak don't add extra salt.
Besides not being preserved in any chemicals - dry scallops also sear much better and much quicker.
Quick is important here - with wet ones, by the time you get a good sear on the outside, they're usually overcooked inside and fresh scallops are best just barely cooked in the center.
(Tip: don't be afraid of a high flame with scallops, and resist the urge to turn them before they're good and brown - only turn once.)
I can not get dry scallops in my area but I love to eat them and cook them. I compensate for the WET type by doing 2 things....I cook them in a hot, hot, smoking hot, well-seasoned cast iron pan with no oil in the pan only on the scallops. The other say is to wrap them in par-nuked bacon and grill them on the hottest grill you can make. They will shed their water and crust on the outside every time. Better than nothing MrsLarkin and I love scallops.
Phosphates not only preserve the scallops, but raise the pH of the meat, which allows more water to bine to the scallops. This is done in a machine that looks like a giant cement mixer. So, when you buy wet scallops, you are buying what I like to call a sponge . . . lots of water to help profits. If you really want to buy a great scallop, go to a proper fish monger who has them still in the shell and will shuck them for you. Would you buy dead clams? Or dead lobster? Same reason I never buy dead shrimp, only whole, live ones. We are lucky to have a real fish monger in our town.
Costco and Sams Club sell frozen dry scallops by the bag if you have one near you. Thaw properly, pat dry, lightly season, then sear away. Yum!
I'm assuming most scallops on sale in grocery stores, including WF, are wet scallops. How can you tell if what's on offer is dry scallops? I've never seen any marked as such.