Anyone who has had a bite of silky duck confit or crispy duck fat–fried potatoes knows that duck fat is phenomenal for cooking. It imparts rich, meaty flavor to ingredients and then can be used to preserve them as well. And it's not hard to come by, seeing as ducks have so much fat on them to begin with. If you're going to be taking on any of the recipes in this Big Duck Project, knowing how to work with duck fat is a simple but important piece of the equation.
Once you've successfully broken down whole ducks into parts, you will have a nice pile of skin and fat ready for rendering; farm-raised ducks generally yield around one pound of fat trim per bird. I like to start the next steps right away so that I don't end up crowding the fridge with a mess of raw poultry odds and ends that still need to be dealt with.
For this Big Duck Project, our next steps are curing legs for confit, hanging the crowns in the fridge to dry-age, making duck stock, and rendering the fat. Whenever presented with a situation like this that involves a bunch of kitchen tasks to tackle, take a second to assess which ones to get working on first. The general rule of thumb is to begin with tasks that are mostly hands off and take a long time because once you get them working, you can turn your attention to the hands-on projects and start living the multitasking life you've always wanted.
The most hands-off task here is without a doubt the fat rendering, which simply involves slowly heating the duck skin and fat until the fat has fully melted, all of the water content has been driven off by evaporation, and the bits of skin have been gently fried into crispy golden-brown crackling morsels. The best way to do this rendering is also the simplest: in a saucepan on the stovetop.
The Best and Easiest Way to Render Duck Fat: Stovetop
The stovetop method is by far the easiest way to render duck fat, involving the least equipment and cooking steps. All you will need is a heavy-bottomed saucepan, a splash of water, the duck fat and skin, a fine-mesh strainer, and a heat-proof container. If you have cheesecloth in your kitchen, great—we can put it to use here, but it's not essential.
If you're the type of person who insists on using immersion circulators and pressure cookers whenever humanly possible, knock yourself out rendering fat with the gadget of your choice (more on that later). But know that you will be making life harder for yourself. Stovetop takes less time and effort and allows me to keep an eye on it while working on other tasks. If that sounds good to you, here's how to do it.
Cut the Duck Fat and Skin Into Manageable Pieces
When breaking down whole ducks, it's most efficient to cut away fat and skin without worrying about the size of the pieces of trim as you work; just get them off the bird and set aside. However, once you've wrapped up the butchery, take a minute to go back over the fat and skin with your knife, cutting the scraps into roughly equal-sized pieces; around two inches is great. They don't need to be perfect; you just don't want a six-inch piece of skin cooking alongside much smaller ones because they won't cook at the same rate. (Side note: If your knives are on the dull side, no judgment, but you may have better luck snipping slippery fat into small pieces with kitchen shears.)
Combine the Fat With a Touch of Water in a Saucepan
I like to think of rendering fat as the savory sibling of making caramel. Both are fundamentally simple stovetop cooking projects that involve melting ingredients into something delicious, but both run the risk of scorching into an acrid kitchen fail if you try to melt the sugar or render poultry skin in a dry pan. This risk can be minimized by starting both of them with a little water in the pan as a safety blanket. In the case of duck skin, the water heats up and gets a jump-start on the fat-rendering process; by the time the water has evaporated, you'll have enough liquid fat built up in the pan to prevent the solid pieces of skin from burning.
You can render fat and make caramel without adding any water, but you have a smaller margin of error, and you have to pay closer attention to what's happening in your saucepan. The whole point of starting with the fat-rendering project is to get a hands-off task working, so don't be a hero.
A quarter-cup of water per pound of duck fat is all you need to ensure that the pieces of skin won't stick and scorch to the bottom of the saucepan as they cook (so if you broke down two ducks, you will probably need 1/2 cup of water). There's nothing wrong with adding more water than that, except you'll have to wait even longer for it to fully cook off.
Use a heavy-bottomed stainless steel saucepan if you've got one, as it will provide nice even heat distribution and its shiny reflective surface will allow you to clearly monitor the progress of the rendering. Cast iron skillets work fine as well, but it's harder to track the color changes of the fat during cooking, and they're more heavy and cumbersome to maneuver when it comes time to strain the fat at the end.
Cook the Fat Low and Slow
Get the saucepan on the stovetop, set it over a medium-low flame, and let it do its thing. You can give it the occasional stir with a rubber spatula to make sure nothing is sticking to the bottom of the pot, but other than that, it won't require much babysitting.
As the fat starts to render you will notice how the liquid that begins to accumulate starts out milky and cloudy. That is water trapped and suspended in the melting fat as an emulsion, much like a vinaigrette.
As the mixture comes to a simmer, it will start out with a cloudy appearance, bubbling rapidly, making it hard to see through the surface. The natural water content in the duck skin and fat, as well as the water added to the saucepan at the beginning, is being driven off through evaporation.
Gradually, the bubbles on the surface will become clearer and will begin to subside, revealing clear, golden-hued duck fat and bits of skin gently frying in the rendered fat. If you've ever made a batch of brown butter before, you should be familiar with this cloudy-to-rapid-bubbling-to-calm-and-clear fat. It's the same process of heating to drive out moisture.
Keep cooking the morsels of duck skin, stirring them occasionally to make sure they cook on all sides, until they are golden-brown and crisp. If at any point the fat starts smoking, turn down the heat or just move the saucepan off the heat completely. The whole process should take between 45 minutes and an hour.
Strain the Fat and Get Crackling
Now all you need to do is strain the fat into a heatproof container through a fine-mesh strainer. If you have cheesecloth handy, you can line the strainer with it to catch any small bits of duck skin sediment. Keeping sediment out of the fat will extend its long-term storage shelf life, but seeing as we will be using the fat very soon for the duck confit part of the Big Duck Project, this isn't much of a concern here.
You should now have a decent amount of clear liquid-gold duck fat and a strainer basket full of crispy, delicious duck cracklings (aka "quacklings"). Do not toss those cracklings! They are your first cook's snack reward of the Big Duck Project. I highly recommend tossing them in a bowl with za'atar and coarse sea salt while they're still hot, for a super-simple tasty snack. You can also use them wherever gribenes (a byproduct of making schmaltz, see our recipe here) are called for, such as in chopped liver.
As for the fat, use your noggin when storing it. You're going to refrigerate it until you're ready to make confit or duck fat potatoes, but keep in mind that you will eventually need to melt it down again. So it's in your best interest to store it in a heatproof container that can go in the microwave, oven, or on your stovetop. If you plan on making confit soon, you can transfer it directly to a lidded saucepan and pop that in the fridge. Mason jars and Pyrex containers are great, too. If you don't have immediate plans for the fat, you can also divide it into freezer-safe containers, label them, and freeze for long-term storage.
Can You Render Duck Fat Sous Vide?
Okay, so you want to know if you can use an immersion circulator to render duck fat. Technically, yes, you can do it, but it really is not worth the time or effort. Fat renders at high temperatures, which is why cooking sous vide duck breast is kind of a pain in the butt—in order to render enough fat on the breast, you end up having to pre-sear it, then cook it sous vide to the desired doneness (medium for duck breast) which is too low a temperature to render fat, and then sear it again at the end to crisp the skin. Not worth the trouble and the same goes for rendering plain fat sous vide.
The fastest way to do it, which is not fast or efficient at all, is to grind duck skin and fat through a meat grinder, bag it up, and cook it sous vide at 185°F (85°C) for one-and-a-half hours until the fat is rendered. But the job isn't done then. Because with sous vide cooking you lose out on the water evaporation of the stovetop method, and all that water is still in the bag with the rendered fat. So you now have to strain and chill the mixture down until the fat rises to the top and solidifies so that it can be separated from the jelly-like duck water. Have fun with that.
Can You Render Duck Fat With a Pressure Cooker?
What about rendering in a pressure cooker? Again, you can do it, but it's more trouble than it's worth. This Modernist Cuisine recipe for pressure cooker–rendered fat takes two hours, also requires Mason jars and grinding poultry skin, and leaves you with the same issues of zero evaporation. Again, knock yourself out if that sounds like a good time to you.
How Long Will Duck Fat Keep in the Fridge?
However you end up with rendered duck fat, you probably want to know how long it will keep, and the answer is a long time! If properly stored in a clean airtight container in the cold part of the fridge, duck fat should keep for six months or longer. Remember, confit was originally all about preservation, and that was well before refrigeration. So yeah, duck fat will keep for a long time. Whenever you do use it, just give it a sniff to make sure that the fat hasn't gone rancid. You'll know pretty easily if it has.
As mentioned earlier, you can also freeze duck fat for long-term storage. Stored in an airtight container in the freezer, duck fat will keep for well over a year.
Can You Reuse Duck Fat From Duck Confit?
Once you do use the fat for a round of duck confit, you may be wondering if you need to toss it once you've gone through all of the tasty duck legs. Nope! You can reuse the fat for subsequent rounds of confit or other duck fat–related recipes.
Just strain the fat into a clean container and pop it back in the fridge. Once the fat has chilled and solidified, you can separate it from the jellied duck confit juices that will have settled at the bottom of the container. Don't throw those out either; they are full of flavor and gelatin, and they are perfect for adding to stews, ragù, roasted vegetables, and more.
You should be able to reuse duck fat at least three times for confit before it gets too salty from the duck leg cure and needs to be tossed. Clearly label what number use you're on when you store it and give it a taste before cooking just to make sure it's not overly salty.
Can You Use Store-Bought Duck Fat?
While rendering duck fat yourself is a great way to utilize all parts of the bird and reduce food waste, odds are you aren't going to be breaking down flocks at a time in order to yield enough fat for batches of traditional confit. This is part of what makes Daniel's sous vide duck confit recipe so appealing. It requires a fraction of the duck fat needed for the traditional cooking method.
However, not everyone has an immersion circulator at home, so I will be providing recipes for old-school, and one not-so-old-school, duck confit that requires more duck fat than you may get from breaking down whole ducks. Fortunately, a lot of grocery stores now sell containers of duck fat (even ones that don't carry whole ducks, which is a bit of a head-scratcher), and duck fat can also be easily purchased online from purveyors like D'Artagnan. Store-bought duck fat is totally fine to work with; every restaurant where I cooked purchased tubs of it to supplement the fat that we got from breaking down cases of ducks.
So that's the skinny on fat-rendering. The simplest way is the best way, and it allows you to focus on the rest of the remaining tasks for the Big Duck Project.