In the days before kitchen ranges became common, baking bread was a major undertaking. In some parts of Europe, it was common to bake a month's supply at a time and dry the bread for storage. One method of drying bread that has survived into the modern age is the production of rusks, or zwieback, for eating whole or to provide crumbs as a recipe ingredient.

Rusks are made by slicing loaves of bread, then baking the slices in a warm oven until they are completely dry. This was originally a means of preserving the bread, which became too dry to support mold or bacterial growth. The rusks could be eaten as they were, with cheese or preserves, or softened with water for the elderly. They could also be added to a bowl of soup to make it more substantial. Rusks are also known by the German name Zwieback, meaning "twice baked." Biscotti, the hard Italian cookie, is made using the same method.

In the countries around the Baltic Sea, where rusks are popular, they are used as crumbs for baking. Because they are baked rather than dried out over a period of days, rusks are crisp rather than hard, and are easy to crumble. They have a better flavor than breadcrumbs, because they are dried, but not stale. In much of Europe, rusk crumbs are used instead of breadcrumbs for baking.

Rusk crumbs have a multitude of uses in the cuisine in the Netherlands, Belgium, Denmark and the Baltic areas of Germany. They are the common choice for any item of meat, fish or poultry that is to be breaded and fried, for example. Rusk crumbs are often fried in a small amount of butter, then sprinkled over vegetable dishes or sauces as a garnish and to provide a contrasting texture. Rusk crumbs are used in stuffing for fish and poultry, and some varieties of dumplings are made from the crumbs.

Rusk crumbs are equally valuable in the production of sweets and other baking. A rustic Danish dessert is made from alternating layers of rusk crumbs and applesauce, garnished with red currant jelly. There are also a number of cakes and puddings in the European repertoire that consist of cake or rusk crumbs, combined with sugar and a variety of dried fruits and spices. Rusk crumbs are used to make crusts for tarts, and some of the oldest recipes for pumpernickel call for a quantity of rusk or bread crumbs in the dough.