Making meringue isn't a simple matter of whipping egg whites, it's an exercise in manipulating egg proteins for baking. There’s a bit of know-how involved, including stabilization tactics and being able to differentiate soft peaks from stiff ones.

What is meringue anyway?

To be precise, meringue is sweetened whipped egg whites. But we can’t talk about meringue without addressing plain whipped egg whites first. There are two primary uses for whipped egg whites: They can be used to lighten batters or fillings, like in our Chocolate Olive Oil Cake, or they can be made into meringue by adding sugar. That meringue, in turn, can be further transformed into a glossy buttercream icing, marshmallows or a show-stopping pavlova.

When you whip egg whites to lighten batters, stabilization isn’t necessary. You don’t need them to keep their shape very long. These whites should be used right away—fold it into the batter and get it in the oven, so there’s no chance for it to weep or break down. Meringue, however, does need to last, and its structure needs to be tight. That’s when stabilizing becomes important.

Sugar stabilizes egg whites

Sugar doesn't just sweeten, it stabilizes. But you have to add it early so it has time to dissolve. Once dissolved, it makes the liquid white thick and viscous, which slows drainage (also called weeping) and makes all of those little air bubbles harder to pop. This combination of egg white and plain white sugar meringue is called French meringue or American meringue.

But uncooked sugar is the bare minimum for stabilization. Combining it with one of the following will help make your meringue even stronger and give it a silkier appearance.

Heat helps strengthen the meringue. Both Swiss meringue and Italian meringue call for some heat. In the Swiss variety, egg whites and sugar are heated over a hot water bath until they hit a temp somewhere in between 145°F and 155°F. In Italian meringue, the sugar is heated separately, then poured directly into the whipping egg whites. Both heating methods ensure the sugar has dissolved and some of the proteins have denatured. When whipped, the proteins can form a stronger, tighter network, making the bubbles so fine that they’re nearly invisible, and making a meringue that can be handled—whether it’s piped into cookies, mixed with chopped nuts or spread onto a cake—without deflating.

A little acid doesn’t hurt. Another common way to stabilize your meringue is to whip a small amount of acid into the whites, like cream of tartar or lemon juice. This addition keeps the protein structure looser, more flexible and less brittle, so the walls of air bubbles can expand to accommodate more air. (It's also less likely to deflated, even if you whip it a touch longer than you should.)

Peak types and when to use them

There are three major types of peaks for meringue: soft, medium and stiff. It’s possible, of course, to fall somewhere in between those peaks, but for the most part, those are the benchmarks.

The soft peak stage comes first. The meringue will be fluffy, leave billowing ripples in the wake of the whisk and, when you take the whisk out and flip it upright, you’ll see the peak gently flop over onto itself. Use meringue whipped to soft peaks when you want to incorporate it into a delicate or liquidy mixture, or if you’re using it as a soft topping for a pie or cake.

The medium peak stage takes a bit longer (seconds, usually not minutes), and the ripples in the bowl will look sharper than they do at soft peak stage. When you flip the whisk over, the meringue’s peak will curve over like a cartoon image of soft serve ice cream. Use medium peak meringue when incorporating into other fluffy mixtures, like for chocolate mousse or soufflé.

Stiff peaks will come along next—and rather suddenly sometimes, so keep an eye on it. You can even whisk the last bit by hand to ensure you don’t overwhip the eggs. At this stage, the meringue has plenty of sharp ripples and lines in the bowl, and when you flip the whisk over, the meringue peak stands straight up. Its signature characteristic is that it can hold its shape but will still be glossy and flexible, not dry. This stage might be the most versatile. It has enough loft and shape-holding power to be piped out into cookies, or spread into a disk to make a pavlova. It has enough strength to be aggressively handled; nut flours can be mixed with it to make dacquoise layers, or butter can be blended in for silky buttercreams. That flexibility means that, like medium peaks, it can also be incorporated into mousses and soufflés without leaving clumps of egg white behind.

Overwhipped meringue is not really a stage, but it is something that can happen if you take your meringue too far. The mixture becomes gritty, broken, and looks like bubble bath foam left past its prime. The mixture will lose its glossy appearance and you’ll likely see liquid collecting at the bottom of the bowl as the proteins expel water and deflate. This isn’t really a place you want to end up, so don't be shy about using stabilizers like acid or heat.

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Allie Chanthorn Reinmann

Allie Chantorn Reinmann is a Digital Staff Writer for Christopher Kimball’s Milk Street. She’s a Thai-American chef who earned her diploma for Pastry and Baking Arts at The Institute of Culinary Education and worked professionally for over a decade honing her craft in New York City at places like Balthazar, Bien Cuit, The Chocolate Room, Billy’s Bakery and Whole Foods. Allie took her know-how from the kitchen to the internet, writing about food full-time at Lifehacker for three years and starting her own YouTube channel, ThaiNYbites. You can find her whipping up baked goods for cafés around Brooklyn, building wedding cakes and trying her hand (feet?) at marathon running. She’s working on her debut cookbook and lives in Brooklyn, NY.