Meringues are built around sugar and egg whites. But despite this simplicity, there are a number of techniques to making the perfect meringues:
1. Check your weather forecast. Heavy humidity will cause the meringues to weep, toughen, and lose their volume.
2. Keep clean. Make sure your mixing bowls and beaters are spotless; any oils from your fingers or specks from previous dishes will inhibit the egg whites from whipping. Along these lines, be sure that the egg whites themselves are spotless. Any egg yolk will have the same inhibiting effect.
3. Be patient. Separate the eggs while cold, but then allow the egg whites to reach room temperature. Egg whites at room temperature will produce a greater volume.
4. Add your ingredients when it’s appropriate. Add cream of tartar at the beginning of the beating to stabilize the egg whites – use 1/8 of teaspoon for every egg white. Add the sugar after soft peaks have formed and do so gradually, adding one tablespoon at a time.
5. Stop beating at the right time. Overbeating reduces the volume and gives the meringues a curdled look. Underbeating will cause the meringues to shrink and have a slick surface. You want to beat the egg whites until the meringue turns glossy, and when the beaters are lifted, the egg whites form stiff, pointed peaks that do not fall over.
6. Maybe add cornstarch. I have not tried this, but some articles recommend adding cornstarch to the meringue to prevent overcooking. For every four egg whites, dissolve one tablespoon of cornstarch into 1/3 cup of cold water. Heat the mixture until the starch thickens, and then set aside to cool. After the sugar has been added to the meringue, you would add the cool cornstarch mixture one tablespoon at a time, beating until stiff peaks form.