How to Make Classic Duck Confit (and Give It a Koji Twist)

The pros, the cons, and the how-to for classic and not-so-classic duck confit.

Pulling a leg of koji duck confit out of a saucepan of duck fat.
Photographs: Vicky Wasik

I'm not the type of cook who thinks traditional, time-consuming cooking techniques are inherently better than quicker modern ones. Got a better, simpler, more efficient way of doing things? I'm all in. I love learning new methods and approaches to food and always bristled at the "because that's the way it's done" reasoning used by a lot of chefs to dismiss questions from inquisitive cooks.

At the same time, there is value in having a solid grasp of fundamental culinary techniques. It's like learning to play an instrument (which I failed at miserably as an ADD kid precisely for this reason)—building from the basics allows you to more easily riff on them as you progress in your playing. Just as music teachers bemoan kids like me who want to play Nirvana in their first guitar lesson, I get texts all the time from chef friends complaining about young cooks in their kitchens who can recite passages from Modernist Cuisine but struggle to put together a simple, tasty dish for a family meal.

When mapping out plans for the Big Duck Project, I combed through the Serious Eats recipe archives to see what recipes had already been covered by the culinary team and noticed that while Daniel had developed an awesome recipe for sous vide duck confit, we didn't have a low-tech, classic duck confit recipe of our own.

Overhead of ingredients for koji-cured duck confit.

Before we go any further, I'd like to state that I agree with Daniel that sous vide duck confit is excellent. It's one of the best applications for immersion circulator cooking and the most efficient confit method for home cooks, producing consistently silky, tender results with minimal effort. That said, there are some drawbacks to sous vide confit, and there's a case to be made for the traditional approach. Seeing as low-fi culinary fundamentals are already part of the Big Duck Project, with basic butchery, stock-making, and dry-aging, it only made sense to tackle classic confit as well (while also sneaking in a not-so-classic riff along the way).

I don't think one method is far superior to the other, so to help you make the call on whether to go with analog or digital confit, I am turning to the tried-and-true technique for hemming and hawing over issues: a pros and cons list.

The Pros of Traditional Duck Confit

So what does traditionally prepared duck confit have going for it, other than the fact that making it gives you the cred to throw some scornful Parisian side-eye at anyone who could be so gauche as to serve a winter cassoulet without it? Here are the highlights.

No Gadgets Required

Lowering duck leg into saucepan of rendered fat.

This one is pretty obvious. The farmers of southwest France who first came up with the idea of extending the shelf-life of duck by cooking and preserving it in rendered fat certainly didn't have nifty, WiFi-enabled immersion circulators at their disposal. Plenty of people these days don't own a sous vide device either. If you fall into that camp, then old-school confit is your only real option.

Most people have an oven (and if you don't, you can cook confit on a stovetop), and an oven-safe vessel that can snugly fit a few duck legs submerged in fat. That's all the equipment needed for traditional confit. No apps or Bluetooth connections required.

Complex Flavor Exchange: Meat and Fat

Pulling a leg of koji duck confit out of a saucepan.

Before cooking, classic confit recipes call for curing duck legs for a day or two with salt, spices, herbs, and often aromatics. The cure deeply seasons the meat, which then imparts flavor to the fat that it is cooked in.

Once the confit has finished cooking, the flavors of the confit and the fat that it's stored in continue to develop as the confit ages and "ripens," a process that preserved meat purists will argue is essential to duck confit.

With sous vide confit, that ripening flavor development isn't possible, as the duck legs are not cooked or stored in the amount of fat required for long-term preservation, which gives confit its name ("confit" is French for "preserved.") That's certainly not the end of the world; home cooks in the 21st century aren't generally looking to preserve meat in their fridge for months on end. But with sous vide confit, you do lose out on the flavor that the duck legs lend to the rendered fat they are cooked in, which can be reused for exponentially tastier batches of confit or to lend meaty richness to vegetables without having to spend money on meat.

Long-Term Storage

Two lidded saucepans with duck confit on stovetop.

As mentioned above, the whole point of confit originally was preservation. The copious amount of rendered duck fat used in classic recipes is what allows the duck to keep for months and months without spoiling. The fat that the duck is submerged in forms a protective shield from air that would cause the meat to go bad.

Because the sous vide confit method doesn't use any additional duck fat (the only fat rendered comes from the duck legs as they cook), the long-term storage options of traditional confit don't apply. Sous vide confit is best enjoyed within a week of cooking. Classic confit can be stored in the refrigerator for at least a month and really a lot longer than that—I have a batch ripening right now in the test kitchen fridge that I made two months ago.

One side note on long-term preservation for duck confit. If you plan on storing it for longer than a couple of months, it's a good idea to procure some sodium nitrite, also known as "pink salt" (labeled "#1"), to add to the salt cure that gets sprinkled over the duck legs before cooking.

Overhead comparing duck confit made with legs cured with pink salt and kosher salt, and legs cured with just kosher salt. The meat on legs cured with pink salt is rosy, while salt-cured legs are brown.
On the left: Confit cured with pink salt and kosher salt. On the right: Confit cured with kosher salt alone.

Sodium nitrite—which is used for meat-curing recipes that involve cooking, brining, smoking, or canning—inhibits the growth of harmful bacteria (which proliferate in anaerobic environments) that can cause botulism. For long-term storage safety, charcuterie expert Brian Polcyn recommends adding 1 teaspoon of pink salt to the cure for every 5 pounds of meat. For our purposes, that translates to a half-teaspoon (3 grams) of pink salt, as we are working with four duck legs that weigh in around 2 1/2 pounds. Along with preventing botulism, pink salt also preserves the rosy hue of meat, as you can see in the photo above. The duck legs on the left were cured with pink salt, while the ones on the right with kosher salt alone.

The Cons of Traditional Duck Confit

Not everything about traditionally cooked confit, whether cured with pink salt or not, is rosy. There are some drawbacks to preparing classic duck confit, and it's worth acknowledging them.

More Fat Needed

Closeup of duck fat rendering in a saucepan.

One of the most appealing things about sous vide duck confit is that it doesn't require any additional rendered duck fat; the fat that renders naturally from the duck legs during cooking is sufficient in the tight vacuum-sealed bag. Traditional confit requires a good amount of rendered fat to submerge the duck legs for cooking them. Because the legs need to be completely covered, the amount of fat required is dependent on the number of duck legs being cooked and the size and shape of the vessel they are to be cooked in.

I recently wrote about how to render the excess fat collected when breaking down whole ducks, but even if you start with that step, it may not produce enough rendered fat to make a decent-sized batch of duck confit. That means you will likely need to purchase a container of rendered duck fat along with the duck itself. Not a dealbreaker, but it is a bit of a nuisance.

More Hands-On and Space-Consuming

Wiping off allium cure from raw duck legs.

With a one-day precooking curing step followed by a low and slow turn in the oven, traditional confit takes more effort to make than sous vide confit, which simply involves combining the duck legs with seasonings in a vacuum-sealed bag and dropping them in a water bath for a set-it-and-forget-it period of 36 hours (just don't forget to cover the water bath to prevent the water level from dropping due to evaporation).

And when the confit has finished cooking, there's the space issue of storage. Sous vide confit has a pretty small footprint—it's not hard to fit a bag with four duck legs in your fridge. Traditional confit, on the other hand, takes up a lot more room, thanks to all that duck fat that's staving off spoilage. If you are tight on space, you might not love the idea of constantly bumping into a big crock of solidified duck fat every time you root around in the fridge.

How to Make Traditional and Koji Confit in the Oven

With the pros and cons of classic confit all laid out, let's go over the broad strokes for making it. Oh, and because sticking to the basics has never been my jam, I also riffed on the traditional method for a koji duck confit that is pretty ridiculous. If you took my recent advice and made a batch of shio koji, this is a great way to put it to use.

Step 1: Cure Duck Legs

Photo collage of salting duck legs for confit.

Traditional confit starts with an overnight cure for the duck legs, which always involves salt to season them, and then usually includes spices and aromatics of some kind. For my classic version of confit, I season duck legs with kosher salt and then buzz up a simple mixture of alliums in a food processor.

Photo collage of ingredients for allium cure in food processor, before and after being processed.

This is a method that was used at a fine-dining restaurant that I cooked at in Boston. We would take shallot scraps from making Thai-style fried shallots along with onions, garlic, and whole sprigs of parsley, and pulse them until processed to a rough paste.

Photo collage of layering duck legs in a baking dish with allium cure, thyme, and peppercorns.

That allium paste gets spread into a non-reactive container, then thyme sprigs and peppercorns are sprinkled over top. The seasoned duck legs then are arranged on top of the paste, and that layering process is repeated so that the duck legs are covered with the mixture on all sides. The whole deal gets wrapped up and popped in the fridge to cure for at least a day and up to two.

Photo collage of curing duck legs with shio koji, black peppercorns, and star anise in a zipper-lock bag.

The koji version I developed is even simpler, provided you have the shio koji ready to go. To maximize contact with the koji and not waste a ton of it in the process, I cure the legs in a zipper-lock bag, combining duck legs with a healthy coating of the koji marinade along with peppercorns and star anise pods. Due to the high salt content and enzymatic activity brought by the koji, the duck legs must be cured for no more than 24 hours, and they are good to go after just 12.

Photo collage comparing traditional and koji-cured duck legs.

I tested with longer cure times and found that the texture of the duck legs began to suffer after two full days of curing. After three days, they were fully over-cured the legs, making them both too salty and too firm.

Step 2: Rinse and Dry Legs

Photo collage of rinsing off allium from duck legs, then patting dry with paper towels.

Once the legs have cured, it's important to rinse and wipe off the cure before cooking. Leaving the cure on the legs will gunk up the duck fat and shorten its shelf-life; it can otherwise be saved and reused for multiple rounds of confit or other recipes. Rinsing off the cure also ensures that the meat and the fat it's cooked in don't end up overly salty.

Step 3: Melt Duck Fat, Submerge Legs

Photo collage of melting duck fat in saucepans on the stovetop and then adding raw duck legs to make confit.

One of the funniest and scariest episodes from my restaurant-cooking days happened at the same restaurant where I picked up that allium cure technique.

The cook who was in charge of making confit at the time had to melt down duck fat for a batch of confit and decided to do that by placing a 12-quart plastic Cambro container of duck fat on a metal shelf situated over the French top range. He was in the weeds and forgot about the duck fat during prep until the bottom of the container melted and duck fat poured onto the flat-top range, igniting into an Apocalypse Now-esque wall of fire on the line. By some miracle, this didn't set off the fire-suppression system. But yeah, make sure to melt down duck fat in a heat-proof vessel.

Overhead of saucepans with traditional and koji-cured duck legs covered in melted duck fat before cooking.

When working with four duck legs, I like to use a 3-quart saucier, which is big enough to hold the legs in a single layer, but does so very snugly so that you don't need a ton of rendered fat to cover them.

Step 4: Cook Low and Slow in Oven

Testing doneness of koji duck confit with a paring knife.

With the legs fully covered in melted fat, pop a lid or some foil over your cooking vessel and transfer it to a low oven (I developed the recipe cooking the legs at 225°F). Now it's a waiting game: the low-temperature cooking takes a while (3 1/2 hours), but you will be rewarded with silky, tender confit.

Photo collage comparing meat of koji confit and traditional confit.

Here's what to look for when checking the legs for doneness. For both the classic and koji versions, the meat should offer very little resistance when poked with a paring knife, and it shouldn't take much effort at all to pull away pieces of meat.

Photo collage comparing skin side of koji confit and traditional confit. skin on koji confit is golden brown while traditional is much paler.

As you can see, the natural sugars from the shio koji give the skin a darker hue than the allium cure. Another good indicator of doneness for duck confit is that the skin around the bottom of the drumstick will begin to contract and pull away from the bone.

As with good barbecue, the goal of a confit isn’t to cook the meat until it “falls off the bone.” Ideally, the meat will still have some chew to it; also, it should stay attached to the thigh and drumstick bones, otherwise it will be almost impossible to keep the leg meat intact as you reheat, crisp, and serve the duck leg.

Step 5: Cool and Refrigerate

Overhead of saucepans with traditional and koji duck confit.

Once the confit has finished cooking, give it time to cool to room temperature, keeping it in its cooking vessel fully submerged in fat. Pulling the duck legs out of the fat before they have had a chance to cool will cause them to dry out. You don't want to pop a steaming saucepan of duck fat into your fridge, which would raise the fridge's temperature, warming up the rest of the products in it. Just take the lid off the confit, and let it cool on your kitchen counter.

I recommend letting the confit hang out for at least one day before enjoying it, especially if you want to crisp up the skin for serving. When the confit is fresh out of the oven, the skin is very soft and fragile, and it will easily tear or slough off if you move it around too much. Just be patient. Keep the confit in the saucepan, cover it back up with a lid, pop it in the fridge, and let it sit for a day or two. Or forget about it for a month to truly ripen it. With this classic cooking method, time is on your side.

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