What Is the Difference Between French, Swiss, and Italian Meringue?

French meringue is the simplest of the three. Begin whipping the egg whites; once they are foamy, add the sugar gradually and keep whipping until the mixture is glossy. It is quick, but it is the least stable of the three; if left to stand, it releases liquid and deflates. For that reason, use it as soon as it is made. Most meringues folded into cake batter, dried in the oven, or spread over a dessert and baked are made this way. Because French meringue contains raw egg whites, it is not recommended for desserts that will be eaten without cooking.

For Swiss meringue, the egg whites and sugar are combined from the start. Put these 2 ingredients in a bowl, set the bowl over boiling water, and heat the mixture while stirring constantly until the sugar has dissolved completely. If the meringue will be eaten without further cooking, heat the mixture until it reaches 71°C / 160°F on a thermometer. Remove it from the heat and whip until the bowl has cooled. The result is denser and glossier than French meringue. If you stop stirring while heating, the egg whites will curdle, so stay with the bowl. Do not let the bottom of the bowl touch the boiling water; heat should be transferred indirectly through the steam.

For Italian meringue, cook the sugar separately in a saucepan to make syrup. Begin whipping the egg whites; when the syrup reaches its target temperature, pour it in a thin stream down the side of the bowl while the whisk is turning. The boiling syrup heats the whites and sets the proteins. This is the most stable of the three meringues; it holds its shape for hours and keeps its form when cut. It also requires the most attention because two tasks happen at once. For that reason, Italian meringue is the most reliable choice for large trays and preparations made ahead of time; still, the hot syrup may not bring all of the whites to 71°C / 160°F, so use pasteurized egg whites if the meringue will be eaten without further cooking.

Their uses follow from these differences. French meringue is used for crisp meringues dried in the oven, pavlova, and cake batters. Swiss meringue is the basis for buttercream and smooth decorations. Italian meringue is used to top lemon tarts, ice cream cakes, and decorations that will not be cooked; because the egg whites are heated by the boiling syrup, it does not need to be cooked further. All three can be folded into cake batter, but meringue is always added at the very end and folded in with a spatula.

The same rules apply across the meringue types. The bowl and whisk must be free of grease; even a trace of fat or egg yolk in the whites can ruin the foam from the start. Fine-grained sugar dissolves more easily. Egg whites whip more readily when close to room temperature. Do not leave any of the three meringues standing for a long time after making them; even the most stable one eventually begins to release liquid. Do not freeze leftover meringue; when thawed, the foam collapses and only a sugary liquid remains.