Wednesday, October 31, 2007

Duck Sous Vide - A Cooking Experiment

Sous Vide is not exactly a new cooking technique, but it is almost completely unknown in the home kitchen. It's scientific nature, not to mention the high startup cost for equipment, has largely relegated it's use to high end restaurant kitchens. But after watching this season of Top Chef where the winner, Hung, made liberal use of this technique, I was determined to give it a try.

In sous vide cooking, the raw items (usually some sort of protein) are placed in a plastic bag which is then vacuum sealed to remove all air and create a watertight seal. The bag is then placed in a water bath, heated to some precise temperature, and left for an amount of time chosen specifically to acheive some particular effect. Sounds complicated, but check out this example and you'll see how simple it really is.

Suppose you would like to cook a steak to a perfect medium rare (135 deg F internal temperature). Using traditional cooking methods, it can be tricky to know just when to take the meat off the heat. Too soon, and the steak will still be speaking to you. Too long, and you will be enjoying(?) a nice plate of sawdust. Even if you monitor the internal temperature, there is still carryover to worry about. Now instead, if you placed the steak in a vacuum sealed bag, heated a water bath to exactly 135 degrees, and placed the steak bag inside, in about 30 minutes, the steak will reach equilibrium with the water - that is to say that the entire piece of steak will be at 135 degrees. What's more, is that if you were to leave the steak in the water bath for an additional 30 minutes, the temperature would not increase at all! Thus, you will have a perfectly uniform piece of steak, cooked perfectly to medium rare throughout. And since the steak has not been subjected to harsh heat, the protein fibers will not tighten up and expel their moisture - meaning a more tender and juicy piece of meat. This is but one basic application of sous vide.

The tricky part is to keep the water bath at precisely the desired temperature. In some advanced sous vide techniques, a difference of even 1 degree could completely change the outcome. This is largely where the expensive startup costs come from. Some companies are now making dedicated equipment to manage the water temp (like Cuisine Technology's Thermal Immersion Circulators). At over $900, they are out of reach for the average home cook, but are fantastic gadgets nonetheless.

Vacuum sealers can be another money pit. Professional quality units are in the 4-figure range. Many on various internet forums have reported good results using the Food Saver (for about $100). Although sous vide is French for "under vacuum," the term is a little misleading. Yes, the food is packed in a vacuum sealed bag. But, the cooking itself does not take place in a vacuum.

Fortunately, I don't believe that you don't need any of this equipment to give sous vide a try. We can get around the need for a sophisticad circulator by using a large stockpot full of water. Since water has a high thermal mass, once you've stabilized the temperature at your chosen set-point, it should hold pretty steady for the amount of cooking time needed. A variation of a few degrees up or down won't hurt us if we're doing some basic sous vide cookery. And zip locking freezer bags sound like a poor man's substitue for a vacuum sealer to me.

So here's what you will need:

- large stock pot (the bigger the better)
- thermometer, with range down to 100F
- zip locking freezer bags
- plastic wrap
- stove (in this case, electric is preferable to gas, but whatever)

Before we get started, there are a few things we should keep in mind.

1. The temperature of the water bath will drop a few degrees when the protein is first added, since it will be coming directly out of the refrigerator. Plan for this by starting with a slightly higher water bath temp than the desired finishing temp.
2. Since the protein will not be exposed to high heat, it will not have a tasty brown crust on the outside. This can be fixed by quickly searing the meat on high heat once the sous vide cooking process is finished. But be careful - you've invested all this time and effort to bring your protein to the perfect doneness, so don't leave it on the heat for too long and foil this effort. A little oil and 30 seconds max heat exposure should do just fine.
3. If the water temp goes up too high - add cold water to correct. Likewise, you could add hot water if you need to quickly raise the temp.
4. It's a good idea to wrap your protein tightly in plastic wrap before placing in the freezer bag. This way, when you suck the air out of the bag and seal it, the plastic wrap will prevent you from inhaling raw meat juices - yuck! It's important to get as much air out of the bag as possible. Any residual air will cause the bag to float, and will not allow the protein to be in continuous contact with the water.
5. Use freezer bags, or something thicker, otherwise the bag may not be able to stand up to the heat. Also, it's best to stay away from the bags with the sliding zippers. They may close easier, but they are also prone to leaking.
6. It's also a good idea to stir the water frequently to prevent hot or cold spots.
7. Adding aromatics to the bag will perfume the protein as it cooks. But be careful of adding liquids as it makes it difficult to seal the bag properly.
8. I have to add that using this technique can be a strange experience for the senses. There are no sounds, no smells, and you are cooking meat in a water bath that you can safely plunge your hand into. It's just an odd feeling.

Got all that? Okay, let's roll.

Duck Breast Sous Vide

1 duck breast, skin removed and reserved
3 slices orange peel, julienned (skin only, no white part)
Fresh ginger, several paper thin slices
Salt and pepper

For the sauce
2 T Grand Marnier
1 C orange juice
1 C duck or chicken stock
1 t finely grated orange zest
2 T butter

Prepare the water bath by filling stockpot and heating the water to 145F. Mount the thermometer on the inside of the stock pot, so that you can continuously monitor the water temperature. Adjust the burner power so that the water temp is stabilized (for my stove, it was on 25% power - about medium low).

Season the duck breast with salt and pepper. Place on a sheet of plastic wrap and sprinkle top and bottom with orange peel and ginger. Wrap tightly in plastic wrap. Place wrapped duck into a freezer bag. Suck out as much air as you possibly can and seal the bag.

Place bag in stockpot and let cook for 30 minutes, maintaining the water temp at 140F. Stir pot periodically to ensure that there are no hot spots. Also make sure that the protein is completely submerged.

While duck is cooking, score the reserved skin and bake in the oven at 375, until the fat is rendered out and the skin crisps up like bacon. Set crispy skin aside until ready to serve.

When duck is cooked, remove from bag and discard orange peel and ginger. Adding a little oil to a hot skillet, sear on high heat about 30 seconds per side to brown the outside of the meat. Remove meat from pan.

Out of the water bath and removed from the bag.

After searing and slicing. Notice the color of the meat is uniform throughout.

To make the sauce, deglaze pan with Grand Marnier and reduce till almost completely evaporated. Add orange juice and zest and reduce until it becomes thick and syrupy. Add stock and reduce by half. Remove from heat and whisk in butter.

Slice duck thinly on a bias and serve with the orange sauce and skin cracklin.

Now that's a beautiful piece of meat. Not only was the meat cooked perfectly medium (hence the pink color), but the texture was like beef tenderloin. It was the most tender piece of duck meat I have ever eaten. For this plate, I threw in some potatoes cooked in duck fat, as well as some twice-cooked green beans.


Anonymous said...

Your duck looks great. I recently made duck confit at 88C for 8 hours in a rice cooker with a temperature controller called SousVideMagic.

Rich said...

Thanks Edaname! I've never heard of Sous Vide Magic until now, but I checked it out and it looks pretty cool. It certainly would make things easier than manually controlling the stovetop. See here for more info.

PS - I would love your Red Cooked Pork recipe :) I just had this for the first time.

Meyer said...

I have been using the Sous Vide Magic for 4 weeks now, and it just works!

I am using a soup warmer (10 Liter)


Chris said...

Hi Rich:

I used your recipe this weekend and it came out great. The duck bacon was a showstopper!



Suzhou said...

Hi, Rich,
Having worried myself blue and now inspired by your duck recipe, I'm about to buy a Sous Vide Supreme and vacuum sealing apparatus TODAY!

zuviel said...

Rich -- the duck sous vide with "bacon" was a real show stopper -- twice! People said it was the best meal they'd had in 6 months.