When I started off with my sous vide research, my focus was on cooking meats like duck breast, steak and chicken. However, when I started looking around online I noticed that there was some good experimentation happening with cuts like duck leg and other high collagen meats.
While I don't think I'll look at Lamb Shank sous vide for quite some time, duck leg did intrigue me. The reason for this is that duck legs are generally best cooked confit style which is basically in fat. There are two reasons why I have avoided this, first of all it is cost prohibitive since you need a $20 tin of duck fat to cook a $3 duck leg. Secondly, you need to control the temperature and prevent the confit from turning in to a deep fry.
Duck leg sous vide style is an interesting proposition since there is enough fat in the duck skin to self confit once the temperature gets high enough.
Looking around the internet, people have tried ranges between 75 and 83 degrees. For my first attempt, I went with Thomas Keller's recommended temperature - 82.2 degrees over 8 hours.
The recipe below is what I followed and believe me, the results are as good as any restaurant confit that you would have and normally pay upwards of $35 for. The resulting leg was moist, flaky and pulled cleanly off the bone and the skin which was rendered paper thin and wonderfully crispy. The meat also imbibed the subtle thyme and bay leaf flavours. The only thing that went wrong was a small leak in one of the bags. Next time I cook this long we will be double sealing the bags. Overall prep time was about 15-20 minutes and completion about 15.
Sous Vide Confit Duck Leg with Asparagus & Kipfler chips
4 duck legs
1 bunch of fresh thyme
4 dried bay leaves
2 Kipfler potatoes
6 Asparagus stalks
Good quality & fresh extra virgin olive oil
Duck fat (optional)
L: Duck Leg, Bay Leaf, Thyme & Olive oil prior to vacuum sealing
R: Duck Leg, Bay Leaf, Thyme & Olive oil after vacuum sealing
Preparation & Sous vide of Duck
- Take duck legs, wipe down with paper towel and sprinkle liberally with salt, place in fridge for 1-2 hours to dry out
- Pour olive oil in to a small cup and place in freezer for 2+ Hours to set
- Wipe off all salt and excess moisture, place in vacuum bag with 4-5 sprigs of thyme and 1 bay leaf
- Immediately prior to sealing, add in 1 teaspoon of frozen olive oil and vacuum seal immediately (assuming the use of a domestic vacuum sealer which won't seal liquids).
- At this time, boil the Kipfler potatoes for at least 30-40 minutes to completely cook through until tender. Place in to a container and refrigerate.
- Place bags in to water bath at 82.2 degrees for 8 hours.
- Remove duck from water bath and wipe down, remove all thyme & bay leaves remove as much excess moisture as possible taking care not to tear the skin.
- Take asparagus stalks, remove woody base and wash
- Cut Kipfler potatoes in to 4-5mm slices diagonally across the length of the potato
Heat 3 pans.
Pan 1 - On medium-low heat, add a splash of olive oil, add in asparagus and grind some salt over. Asparagus should ever so slightly bubble, not fry and the skin will start to wrinkle. Turn and keep turning until tender (approx 10 minutes)
Pan 2 - Low medium heat, add in a splash of olive oil and place duck leg skin side down to crisp (approx 5-10 minutes, meat won't dry out so cook until potatoes are ready or desired crispiness is reached).
Pan 3 - Add in enough duck fat or olive oil to be at least 3-4mm deep. Put on to a high flame, when fat is hot drop in a slice of potato to ensure it starts frying straight away. Once hot, add in slices slice by slice until all are in and none are overlapping. Turn slices gently every 40-50 seconds until slightly golden. Once cooked remove and place on paper towel, grind salt and pepper over the top.
- Place the duck breasts to overlap on the plate
- Place a small stack of the Kipfler potatoes off to the side
- Place asparagus to balance out the presentation of the plate
Note - Odd numbers are generally more appealing to the eye, so 3 is the ideal number of asparagus stalks.
Also, while I mentioned the high price of duck fat, I don't want to sound like a hypocrite, so if you cook something like duck breast, save the rendered fat for the most luxurious fried potato you have ever had the next day. It should store for at least 1 week in a container in the fridge.
For more understanding of meat collagens and why shallow frying asparagus is the best way to cook it, watch Heston Blumenthal's Kitchen Chemistry Meat and Vegetable episodes.