A meringue can form the basis of any number of wonderful desserts, cookies, and other baked treats. Unfortunately, a long line of home cooks have found themselves frustrated by limp, chewy, or deflated meringues. The next top you're whipping one up for lemon meringue pie or pavlova, avoid these common mistakes and you're guaranteed to come out with a tall, impressive mound of fluff.
Adding the Sugar Too Quickly
Ever attempt a souffle only to watch it deflate? It's because the only thing holding together the batter are the proteins in the egg whites. With a meringue, the sugar interacts with the same proteins to produce a more stable structure, which is why a properly made meringue is much stiffer than an ordinary egg foam. In general, a given weight of egg whites can absorb up to an equivalent weight of sugar, but you can't just dump it in all at once or it will simply knock all the air out of the foam. Instead, add half the sugar with the machine running, a tablespoon at a time. Then, with the machine off, gently fold in the rest with a spatula. Some cooks like to use superfine (aka baker's sugar) or confectioner's (aka powdered) sugar for this second addition—or sometimes even for the whole quantity—as these two will dissolve more quickly.
Skipping the Cream of Tartar
A mild acid will help give your meringue more volume and structure, which means they will inflate more fully and hold the air longer. You don't need much: about 1/4 teaspoon of cream of tartar for every two to three egg whites should do the trick. You can also use lemon juice. About 1/2 teaspoon of lemon juice will contribute the equivalent amount of acid as 1/4 teaspoon of cream of tartar. Outside of making meringues, cream of tartar is a handy item to have in your pantry because you can use it to make your own baking powder.
Using a Dirty Bowl
No one is casting aspersions on your dishwashing skills here, but even the slightest residue of oil on the inside of your bowl, or indeed a tiny speck of egg yolk, will prevent your egg whites from foaming properly, no matter how hard you beat them. Note that the same is true for the whip attachment itself. For this reason, separate eggs one by one into a small bowl, and then add the egg whites individually into the bigger mixing bowl. That way, if a yolk slips through, you need only discard one egg white and not the whole batch. And it isn't just grease: even a wet bowl will prevent your meringue from forming stiff peaks. So make sure your bowl is squeaky clean and dry, and preferably stainless steel, which of course is what most stand mixer bowls are made of. (Even better if you have one is a copper bowl.)
Not Bringing Eggs to Room Temperature
Egg whites will produce a better, airier meringue if they start out at room temperature. A lot of folks will pull their eggs out for 10 or 15 minutes, or even 30, which is certainly better than using them straight from the fridge, but for the very best results, let your egg whites come to room temperature for a full hour. Note that it's easier to separate cold eggs, so your best bet is to separate them while they're cold and then let the whites come to room temperature. Again, be extra careful when separating your eggs because even a tiny speck of yolk can prevent your whites from achieving full peak stiffness. For this reason, separate eggs one by one into a small bowl, and then add the egg whites individually into the bigger mixing bowl. That way, if a yolk slips through, you need only discard one egg white and not the whole batch.
Beating the Egg Whites for Too Long
One of the most common mistakes is not beating the eggs long enough, or on too slow a speed, which means the egg whites won't reach stiff peak stage and instead only reach a soggy droopy stage. But the opposite can also happen: if you beat them for too long, eventually the whites go past peak stiffness to a kind of grainy consistency. The dry and almost lumpy, curdled milk texture is equally undesirable, both aesthetically and functionally. Nor is there any going back. Once your egg whites are overbeaten, they won't work properly in your meringue. Properly-whipped egg whites should look shiny and moist.
Squeezing All the Air Out
This one is a real heartbreaker. If you've done everything properly and avoided all the pitfalls described above, the last thing you want to do is deflate your meringue by squeezing the piping bag too tightly. Squeeze gently and leave a gap between the tip of the bag and the parchment or baking sheet, so that the meringue is not being pressed against the baking sheet.
Baking the Meringues Too Low
This shouldn't be a problem assuming you followed the recipe and your oven is calibrated properly. But if you notice beads of liquid condensation forming on the surface of the meringue while it bakes, that's a sign that your oven temperature is too low. The solution: crank up the heat and shorten the cooking time. Note also that a fully baked meringue should easily pull away from the baking sheet when you lift it with a spatula. If it sticks at all, bake for another few minutes and test again.