White Sauce Can't Clump: How to Make Smooth, Silky Béchamel

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Photographs: Vicky Wasik

I meet, on occasion, people who claim to hate white sauce. It is something I will never understand. Even if you don't enjoy eating plain béchamel (as it's known in France) with a spoon, like I do, who doesn't love a classic lasagna Bolognese, with its meaty ragù layered with the thick and creamy sauce between sheets of fresh pasta? Or an old-school mac and cheese, with the cheese melted into the sauce, Mornay-style? Or a croque monsieur, with béchamel slathered inside and on top of the warm ham-and-cheese sandwich?

Europe doesn't do it for you? How about chicken-fried steak or Maryland fried chicken? Or, even simpler, buttermilk biscuits smothered in sausage gravy? We call it gravy, but it's all béchamel by another name.

Béchamel does so much more, too. It's the base of savory soufflés, the creamy sauce in many vegetable gratins and casseroles, and that lovely layer of custardy dairy in Greek moussaka.

Considering all that, it's no wonder that béchamel is one of the mother sauces in classic French cooking (though it's worth noting that Italians often claim to have originated besciamella, but who knows if that's true). Whether you think you hate white sauce or not, it needs to be in your arsenal of fundamental recipes, something you can whip up at a moment's notice without having to consult a cookbook.

What's in It?

Béchamel, at its simplest, is just milk that's been thickened with a roux made from roughly equal parts of butter and flour. Way back when, it also had veal, onion, and other flavor-enhancing ingredients simmered into (and then strained out of) it,* but today that's almost never the case. A little salt, a little pepper, maybe a touch of grated nutmeg stirred in at the end—that's about it. If you're feeling extra fancy, you can simmer the milk with a bay leaf, thyme, or aromatics like onion and carrot, then strain them out and finish the sauce, but even that is skipped more often than not.

*This video has a good demo on Escoffier's veal-enhanced recipe, if you're curious.

The Ratio

The ratio of flour and butter to milk is the biggest decision you have to make when making a batch of béchamel, since that determines the sauce's thickness.

The answer often depends on the dish. If you're making a gravy, for instance, you'll want a sauce that's more on the pourable end of the spectrum, made with somewhere between one and two tablespoons of flour per cup of milk (about eight to 15 grams per 240 milliliters). A soufflé or moussaka, on the other hand, generally requires a thicker béchamel, made from about three tablespoons (22 grams) of flour per cup of milk—that's thick enough for the béchamel layer to remain distinct atop the ground meat in moussaka, and for the soufflé base to have enough structure that it can rise properly.

In a lot of cases, the ratio you choose just comes down to personal preference: How thick do you want the sauce to be? My go-to ratio is a tablespoon and a half (about 12 grams) of flour (cooked with an equal quantity of butter) per cup of milk, which makes a sauce that's pourable, yet, with just a little simmering, thick enough to evenly coat the back of a spoon.

Remember, though, that béchamel is so easy and forgiving, even if you get the ratio wrong, it's incredibly easy to fix: If yours comes out too thick, just whisk in more milk until the desired consistency is reached; if it's too thin, either simmer it down, allowing evaporation to thicken the sauce up, or cook a little more flour and butter in a small saucepan on the side, then whisk it into your too-thin sauce.

Step by Step: How to Make Béchamel Sauce

Step 1: Melt Butter

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Start by melting butter in a saucepan over medium or medium-high heat. Higher heat will move things along faster, but also carries the risk of browning the butter if you're not careful.

Step 2: Add Flour and Cook

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As soon as the butter is melted, add the flour and whisk to form a paste. Continue whisking as the paste cooks, making sure to reach into the corners of the pan to prevent the paste from scorching. The key here is that you want to cook the raw smell out of the flour, but you don't want the flour and butter to brown in the process. This is called a white roux, i.e., a butter-and-flour mixture that does not grow toasty and browned.

The butter serves two main functions here. First, it helps distribute heat from the pan, allowing you to cook the flour more evenly than if it were dry. Second, the butterfat coats the particles of flour, separating them and making them less likely to form lumps when the milk is added. When you pair that with plenty of thorough whisking, you shouldn't have any issue with lumps.

Step 3: Whisk in Milk

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As soon as the flour has lost its raw smell, start pouring in the milk in small additions, whisking the whole time. Adding in small increments is key. It allows you to ensure that the flour isn't sitting in clumps at the bottom of the pan, which can lead to a grainy or lumpy sauce later on. If you've got good coordination and a nice heavy pan, you can slowly drizzle with one hand while whisking with the other. Otherwise, you can splash in a couple of tablespoons at a time, working quickly and whisking in each addition before adding more.

At first, the roux will seize up into thick balls, but it will smooth out and become liquid again as more milk is added. Once all the milk has been added, it'll usually seem as thin as plain milk. That's fine; just bring it to a simmer, and the flour will start to do its thing, its starch swelling and bursting and thickening the sauce.

It's worth stopping here to point out that some people like to bring their milk to a simmer first and then add it to the roux. I have nothing against this, but I usually don't bother, since it just dirties another pot and, at least in my experience, doesn't ultimately make much difference. At best, the béchamel thickens up a little faster with warm milk added, but that's it.

Step 4: Simmer Until Thickened

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Once all the milk has been whisked in and it's come to a simmer, continue to cook it, whisking frequently, until the sauce hits the consistency you want. As it thickens, you'll see more and more of the pot bottom as you whisk, a sign that all is well in the world of white sauce.

Step 5: Season and Use As Desired

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Season the finished béchamel with salt, black or white pepper, and maybe a dusting of freshly grated nutmeg. If any lumps form, just whisk them out, or use a hand blender or regular blender if anything goes wrong and some major recovery is required. If you're not quite ready to use the sauce, pressing a piece of plastic wrap against its surface will prevent a skin from forming.

When you're ready, just add it to whatever dish you're making, whether you're folding it with ragù for a lasagna or melting in grated cheese for a Mornay sauce. Now tell me, who doesn't like that?