Sea scallops are my favorite meat, but preparing them can be hit or miss. Since they are so delicate, scallops are often overcooked, and while they might remain sweet, this still results in a rubbery dish. Cooking scallops en sous vide makes getting them perfect much easier. And they are perfect. Be careful if you try these -- you'll never enjoy scallops at a restaurant again.
In this recipe, I was generally inspired by Sous Vide Scallops at Believe the Lie, and Twice Cooked Scallops at Ideas in Food.
Here's the short form of the recipe:
Cook scallops with butter, salt, and pepper at 122 F
Chill the scallops in an ice bath
Sear the outside in very hot oil
Step 1: What Is Sous Vide?
"Sous vide" is French for "under vacuum" and cooking en sous vide typically refers to vacuum packing ingredients, then cooking them under very strict temperature control. "Precision cooking" might be a more accurate term, but all gastronomical things tend to gravitate toward the French descriptions. When sealed in plastic, the aromatics cannot vaporize so flavors are more intense, and food can be cooked in water baths held at specific temperatures for long periods of time without the water soaking or otherwise changing the texture of the food. Sous vide is a food service technique that has been embraced by the world's best chefs, and with some equipment that is not outrageously expensive, you can duplicate some of their dishes.
My two favorite references for sous vide are Thomas Keller's Under Pressure and A Practical Guide to Sous Vide Cooking by Douglas Baldwin.
Step 2: Sous Vide Equipment
Restaurant and food service-level sous vide equipment can be quite expensive. Since publishing my Sous Vide Beef Ribs and Sous Vide Venison Instructables, I have upgraded my equipment, but still managed to spend less than $400 for an at-home sous vide setup. I use:
Sous Vide Magic PID temperature controller purchased from Auber Instruments on Ebay
Winco ERC-50 25 cup commercial rice cooker1
FoodSaver Vac 300 Vacuum Sealing Kit
Update: since I purchased my equipment, Sous Vide Supreme has started making an all-in-one unit designed for home use. The regular 10L unit is $400, and the still-quite-roomy 8.7L Demi is $300 - comparison here.
1 A rice cooker or electric kettle can also work; the variables are size of container, and speed of heating. The key is to make sure your heating device doesn't have a brain, as the PID controller works by cycling the power on and off and you can't be resetting your crock pot each time.
Step 3: Vaccum Pack the Scallops and Butter
Vacuum pack scallops, butter, salt, and pepper. Without a chamber vacuum sealer, the colder each item is, the easier it will be to get it sealed as less liquid will be drawn into the sealer's channel.
Step 4: Cook the Scallops
Cook the scallops at 122°F until they reach a uniform internal temperature. Consult A Practical Guide to Sous Vide Cooking time/thickness charts. I cooked mine for 30 minutes.
Step 5: Chill the Scallops
Chill the scallops in an ice bath. Chilling in this way is reported to help set a custard-like interior, and prevent the scallops for dumping all their liquid when you sear them.
The scallops are now cooked, and you could eat them, but to finish and make them a masterpiece, you want to sear both sides.
Step 6: Sear the Scallops
The scallops will have released some liquid into the plastic bag. Remove and dry the scallops and reserve the liquid.
Heat a little bit of oil or butter until it is just smoking, and quickly sear the top and bottom of each scallop. You are aiming to caramelize the surface without further cooking the interior.
After searing (or at the same time in another pan, as my pictures show), heat the reserved scallop-liquid and reduce it. Don't try to reduce the liquid and sear the scallops in the same pan at the same time -- the liquid will keep the temperatures below proper searing levels, and you'll overcook the scallops. The reduced liquid is delicious, and can be poured over the scallops or another accompanying dish.
Step 7: Serve
Serve the scallops immediately. Their flavor should be concentrated, and their texture soft without the need of a knife to cut cleanly through.