How do you like your leg of lamb?
There is debate as to the exact definition of “rare,” “medium rare,” “au point,” etc. A little practice will help you learn just exactly what temperature achieves your preferred appearance of doneness.
Here are some basic temperature setting guidelines:
Rare: 129 F/54 C.
Medium: 135 F/57 C
Medium to Medium well: 140 F/60 C.
Well done: 150 F/74 C.
Level of difficulty: 2.5
Preheat the water in your sous vide bath to the temperature that most closely matches your preference. For this demonstration, we used 130 F/54 C.
Let sous vide timing work for you!
Among sous vide’s several unique characteristics, cooking time is determined by the shortest distance from the surface of the roast to the geometric center instead of by weight. Many newcomers are daunted at first by what appears to be an inconveniently long period of time required to sous vide process proteins.
The fact is, the rate of collagen conversion in this range of temperatures is very gradual. This means that the texture and appearance of a roast processed for 8 hours will differ only slightly, if at all, from a roast that has been processed for 12 hours. Some people want to start their roast in the early morning to serve for dinner that evening, so the 8+ hour interval is convenient for them. Others would rather start it the evening before and sleep in! Both approaches are favorable!
Processing the roast
Vacuum sealing the leg of lamb in heat rated sous vide bags and process at the desired temperature for 8-12 hours, as per your convenience and regardless of the weight.
After processing, shock the sealed pouch in iced tap water to 70 F/21 C before refrigerating. This is a very important safety procedure. The air in refrigerators/freezers is not capable of cooling the pouch fast enough to meet food safety guidelines. After shocking, refrigerate at 40 F/4 C until you are ready to move on to the next step.
Submerge the sealed pouch for 5-10 minutes in a preheated sous vide bath or hot tap water (110+ F/44+ C). This will fully melt the gel. Cut open the bag, drain the juices and set aside. Click HERE to learn how to clarify the juices for use in any recipe that calls for stock or water.
Preheat the oven to 350 F/176 C.
Place the roast on a sheet pan for roasting. I use a sheet of parchment for quick and easy disposal afterwards.
Dust the roast on all sides with powdered egg white. Fresh egg whites can also be used.
Mist with water to create a sticky surface–not necessary if you use fresh egg whites.
Sprinkle all sides liberally with the seasoning mixture.
Stage the roast into the preheated 350 F/176 C oven.
Roast until the surface achieves the desirable appearance and the internal temperature is at least 125 F/52 C–approximately 1.5 hours.