Whether soft and fluffy on a pie, or as a crispy base to Pavlova, snowy white meringue is an ethereal delight.
At its simplest, meringue is made up of just egg whites and sugar. Sometimes salt and an acid, like lemon juice or cream of tartar, is added to stabilize the egg foam.
Use a clean, dry bowl. The bowl must be grease-free, because any trace amount of fat will wreck a meringue. Glass, ceramic, stainless steel, and copper bowls are all suitable. Plastic bowls may appear clean, but may still have trace amounts of oil, so do not use them.
Cold eggs separate easily, but eggs whip to a higher volume when at room temperature. The solution is to separate the cold eggs, and then set them aside for 10 or 15 minutes.
Separate each egg into two small bowls, one for the white and one for the yolk, and then add the white portion to the larger bowl. This allows you to reserve any with broken yolks for another purpose. Even a small amount of yolk can deflate the egg whites, so be careful.
Cream of tartar, white vinegar, or lemon juice can all be used to stabilize a meringue.
Add 1/8 teaspoon of cream of tartar per egg white to the unbeaten eggs. (If you're using a copper bowl to make your meringue, don't add any acid: it can react with the copper and discolor the egg foam.)
Whip to medium-soft peaks. Beat in 2 tablespoons white sugar per egg white. Continue to beat until egg whites are glossy and hold a firm peak.
Adding sugar early in the beating process results in a firmer, finer-textured meringue.
Pasteurizing egg whites is not a concern when preparing a meringue that is going to be baked longer than ten minutes in a moderate oven (350 degrees F/175 degrees C).
For buttercream frostings, baked Alaskas, or meringue pies, however, the egg whites should reach at least 140 degrees F (60 degrees C) for safety's sake. Some supermarkets sell pre-pasteurized egg whites; these require a much longer whipping time to reach the desired volume for a meringue.
Italian meringues are made with a sugar syrup. Sugar and water are boiled to the soft-ball stage (240 degrees F/115 degrees C) and carefully poured in a thin stream into a mixer bowl of whipped egg whites. The mixture is whipped until cool. Because of the constant whipping, the bowl cools quickly, and the egg whites may not reach pasteurization temperature; you can use an instant read thermometer to check the meringue's temperature after the first minute or so of whipping.
Swiss meringues are made by combining sugar and egg whites and heating them over a double boiler.
To prepare a Swiss meringue, whisk the sugar and egg whites enough to break up the whites, but not so vigorously that they form an airy foam.
The sugar will melt and act as a protective shield against coagulation of the egg whites; heat and whisk constantly until the temperature of the whites reaches 145 degrees F or hotter.
Remove the bowl from the heat, and beat the warm egg whites until they form stiff, glossy peaks.
Beading, weeping, and shrinking are common complaints. Overcooking causes beading, the formation of water droplets on the surface. Weeping--loss of water between the meringue and the pie filling--is caused by undercooking. Shrinking is a loss of volume during baking.
Meringue Pie tips
A never-fail method for producing the perfect meringue is one that uses a cornstarch and water mixture to form a gel: beaten gradually into a meringue, the thickener will prevent shrinking problems. See the Never-Ever-Fail Meringue recipe for an example of this technique.
Spread meringue over piping hot filling, and spread to the edges to seal. Hot filling is necessary to ensure that the inside of the meringue cooks, preventing weeping. Swiss or Italian meringues, since they are already cooked, are less prone to shrinking and weeping.
Fine cake crumbs, vanilla wafer crumbs, or soft white bread crumbs sprinkled lightly over the filling will absorb liquid between the layers, another preventative against weeping.
Bake your meringue pie at a high temperature with a short baking time. This prevents overcooking the outer layer of meringue, so beading is avoided. Bake at 425 degrees F (220 degrees C) for 4 to 5 minutes.