Simple Meringue dessert with peanuts. Meringue is often associated with Swiss, Italian and French cuisine, made from whipped egg whites and sugar. Sometimes an acid such as cream of tartar or a small amount of vinegar is added. A binding agent such as cornstarch or gelatin may also be added. The key to the formation of good meringue is the formation of stiff peaks formed by denaturing the protein ovalbumim via mechanical shear. Meringues are often flavoured with vanilla and a small amount of almond or coconut extract, although if these extracts are based on an oil infusion, an excess of fat from the oil may inhibit the egg whites from forming a foam. They are light, airy and sweet confections. Homemade meringues are often chewy and soft with a crisp exterior, although a uniform crisp texture may be achieved at home, whilst many commercial meringues are crisp throughout.
It has been claimed that meringue was invented in the Swiss village of Meiringen and improved by an Italian chef named Gasparini in the 18th century. There are basically three types of meringue which are different in the way it is made. I am using Meringue Italienne, made with boiling sugar syrup, instead of caster sugar. This leads to a much more stable soft meringue which can be used in various pastries without collapsing. Italian meringue is safe to use without cooking. It will not deflate for a long while and can be either used on butter cream, mouse, or base for sherbet, or spread on cakes or even spread on a sheet and baked for meringues.
It is interesting to know the chemistry of these amazing desserts. When egg whites are beaten, some of the hydrogen bonds in the proteins break, causing the proteins to unfold and to aggregate non-specifically. This change in structure leads to the stiff consistency required for meringues. The use of a cooper bowl, or the addition of cream of tartar is required to additionally denature the proteins to create the firm peaks otherwise the whites will not be firm. Plastic bowls, wet or greasy bowls will likely result in the meringue mix being prevented from becoming peaky. Wiping the bowl with a wedge of lemon to remove any traces of grease can often help the process. When beating egg whites, there are three stages according to the peaks they form when the beater is lifted: soft, firm and stiff peaks. The sugar is necessary to the structure. Egg whites and sugar are both hygroscopic (water-attracting) chemicals. Consequently, meringue becomes soggy when refrigerated or stored in a high-humidity environment. This quality also explains the problem called “weeping” or “sweating”, in which beads or moisture form on all surfaces of the meringue. Sweating is a particular problem for French meringues in which the granulated sugar is inadequately dissolved in the egg whites.
Based on my experiences, be extra careful when separating yolk with the egg whites, as yolk contains fat, where even a drop of yolk will not make the meringue mix becoming peaky. Another point to remember is to immediately store the meringues in an air-tight containers with silica gel to avoid the sweeting.