Settlements across the Indus Valley Civilization were the first to have an oven within each mud-brick house by 3200 BC.
Culinary historians credit the Greeks for developing bread baking into an art. Front-loaded bread ovens were developed in ancient Greece. The Greeks created a wide variety of doughs, loaf shapes and styles of serving bread with other foods. Baking developed as a trade and profession as bread increasingly was prepared outside of the family home by specially trained workers to be sold to the public. This is one of the oldest forms of professional food processing.
The Greeks also pioneered sweetbreads, fritters, puddings, cheesecakes, pastries, and even wedding cakes. Often prepared in symbolic shapes, these products were originally served during special occasions and ceremonies. By 300 AD the Greeks had developed over seventy different kinds of bread.
In cooking, the conventional oven is a kitchen appliance and is used for roasting and heating. Food normally cooked in this manner includes meat, casseroles and baked goods such as bread, cake and other desserts.
In the past, cooking ovens were fueled by wood or coal. Modern ovens are fueled by gas or electricity. When an oven is contained in a complete stove, the fuel used for the oven may be the same as or different from the fuel used for the burners on top of the stove.
Ovens usually can use a variety of methods to cook. The most common may be to heat the oven from below. This is commonly used for baking and roasting. The oven may also be able to heat from the top to provide broiling. In order to provide faster, more-even cooking, convection ovens use a small fan to blow hot air around the cooking chamber. An oven may also provide an integrated rotisserie.
Steam ovens introduce water (in the form of steam) into the cooking chamber. This can aid the formation of a crisp crust on baked goods and prevent the drying-out of fish and casseroles. The degree of humidity is usually selectable among at least several steps. Some steam ovens use water carried to the oven by the user in a container; others are permanently connected to the building plumbing.
More modern ovens, such as General Electric's Trivection oven, may also provide combined thermal and microwave cooking. This can greatly speed the cooking of certain types of food while maintaining the traditional characteristics of oven cooking such as browning.
Ovens also vary in the way that they are controlled. The simplest ovens (for example, the AGA cooker) may not have any controls at all; the several ovens simply run continuously at various temperatures. More conventional ovens have a simple thermostat which turns the oven on and off and selects the temperature at which it will operate. Set to the highest setting, this may also enable the broiler element. A timer may allow the oven to be turned on and off automatically at pre-set times. More-sophisticated ovens may have complex, computer-based controls allowing a wide variety of operating modes and special features including the use of a temperature probe to automatically shut the oven off when the food is completely cooked to the desired degree. Orthodox Jews may purchase ovens whose controls include a sabbath mode automation feature.
Some ovens provide various aids to cleaning. Continuous cleaning ovens have the oven chamber coated with a catalytic surface that helps break down (oxidize) food splatters and spills over time. Self cleaning ovens use pyrolytic decomposition (extreme heat) to oxidize dirt. Steam ovens may provide a wet-soak cycle to loosen dirt, allowing easier manual removal. In the absence of any special methods, chemical oven cleaners are sometimes used or just old-fashioned scrubbing.