Staling

Staling, or 'going stale' is a chemical and physical process in bread and other foods that reduces their palatability. Stale bread is dry and leathery.

Staling is not, as is commonly believed, simply a drying-out process due to evaporation. Bread will stale even in a moist environment, and stales most rapidly at temperatures just above freezing. (McGee 2004, p. 310)

Although the precise mechanism of staling is still unknown, one important mechanism appears to be migration of moisture from the starch granules into the interstitial spaces, degelatinizing the starch. This results in stale bread's leathery texture.

Additionally, pleasant "fresh" flavor is lost to the air, and often unpleasant flavor is absorbed from it as well, especially in a confined space with other food such as a refrigerator.

Culinary uses

Specifically-stale bread is an important ingredient in many dishes, some of which were invented for the express purpose of using-up otherwise unpalatable stale bread. Examples include bread pudding, bread sauce, skordalia, garbure, fondue, croutons, haslet, gazpacho, wodzionka, french toast, and flummadiddle.

In medieval cuisine, slices of stale bread, called trenchers, were used instead of plates.

Destaling

Stale bread can be partially destaled by heating to 60°C (140°F) in a conventional oven or microwave oven. This re-gelatinizes the starch granules. However if not eaten before it cools or dries, the bread is even worse than before due to the moisture lost as steam.

Stale bread can also be toasted lightly in a toaster.

See also

• Starch gelatinization

References

• McGee, Harold (2004), On Food and Cooking: The Science and Lore of the Kitchen (2 ed.), New York: Scribner, ISBN 0-684-80001-2
• The study of bread staling using visible and near-infrared reflectance spectroscopy, Feng Xie.