Food Thickeners

Sauces and puddings can be thickened by using various ingredients, including eggs, gelatin, and starches, such as flour, cornstarch, arrowroot, or rice flour. These thickeners may be used to lightly thicken a mixture, as for a sauce, or to produce an item that is firmly set.

The quantity and type of thickener, as well as the amount of stirring or other manipulation, will determine the finished product's properties. For example, if a custard is cooked over direct heat and stirred constantly, the result will be a sauce that pours easily. The same custard cooked in a bain-marie with no stirring at all will set into a firm custard that can be sliced.

Arrowroot and cornstarch are generally preferred for thickening sauces, puddings, and fillings where a translucent effect is desired. If these thickeners are to be diluted before incorporation with other ingredients, they should be mixed with a small amount of a cool liquid.

Flour is commonly used to thicken foods. In order to prevent lumping, the flour and sugar are often stirred together before they are combined with the liquid. Flour-thickened sauces are also often additionally thickened and enriched with eggs. The eggs must be tempered to prevent the sauce from curdling. Eggs (whole eggs or yolks) may be used either alone or in conjunction with other thickeners. As the egg proteins begin to coagulate, the liquid becomes trapped in the network of set proteins, producing a texture, in which the sauce will coat the back of a spoon when the spoon is dipped into the sauce and withdrawn.

Gelatin, when added in the desired amount, can produce light, delicate foams that are firmly set. Such foams will retain a mold's shape and can be sliced. Gelatin is an animal protein found in bones. it is this protein that causes stock to gel as it cools. Gelatin powder or sheets are frequently used for a variety of bakeshop items. Before use, gelatin must first be softened in a cool liquid. Once the gelatin has absorbed the liquid, it is then gently heated to melt the crystals. This is accomplished either by adding the softened gelatin to a hot mixture, such as a hot custard sauce, or by gently heating the gelatin over simmering water.