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Baking is the technique of prolonged cooking of food by dry heat acting by convection, and not by radiation, normally in an oven, but also in hot ashes, or on hot stones. It is primarily used for the preparation of bread, cakes, pastries and pies, tarts, quiches, cookies and crackers. Such items are sometimes referred to as "baked goods," and are sold at a bakery. A person who prepares baked goods as a profession is called a baker. It is also used for the preparation of baked potatoes, baked apples, baked beans, some casseroles and pasta dishes such as lasagna, and various other foods, such as the pretzel.
Many commercial ovens are provided with two heating elements: one for baking, using convection and conduction to heat the food, and one for broiling or grilling, heating mainly by radiation. Meat may also be baked, but this is usually reserved for meatloaf, smaller cuts of whole meats, and whole meats that contain stuffing or coating such as breadcrumbs or buttermilk batter; larger cuts prepared without stuffing or coating are more often roasted, a similar process, using higher temperatures and shorter cooking times. Baking can sometimes be combined with grilling to produce a hybrid barbecue variant, by using both methods simultaneously or one before the other, cooking twice. Baking is connected to barbecuing because the concept of the masonry oven is similar to that of a smoke pit.
The baking process does not require any fat to be used to cook in an oven. Some makers of snacks such as potato chips or crisps have produced baked versions of their snack items as an alternative to the usual cooking method of deep-frying in an attempt to reduce the calorie or fat content of their snack products.
The dry heat of baking changes the form of starches in the food and causes its outer surfaces to brown, giving it an attractive appearance and taste. The browning is caused by caramelization of sugars and the Maillard reaction. However, the moisture is never entirely "sealed in"; over time, an item being baked will become dry. This is often an advantage, especially in situations where drying is the desired outcome, like drying herbs or roasting certain types of vegetables. The most common baked item is bread. Variations in the ovens, ingredients and recipes used in the baking of bread result in the wide variety of breads produced around the world.
Some foods are surrounded with moisture during baking by placing a small amount of liquid (such as water or broth) in the bottom of a closed pan, and letting it steam up around the food, a method commonly known as braising or slow baking.
When baking, consideration must be given to the amount of fat that is contained in the food item. Higher levels of fat such as margarine, butter or vegetable shortening will cause an item to spread out during the baking process.
With the passage of time breads harden; they become stale. This is not primarily due to moisture being lost from the baked products, but more a reorganization of the way in which the water and starch are associated over time. This process is similar to recrystallization, and is promoted by storage at cool temperatures, such as in a domestic refrigerator.
In ancient history, the first evidence of baking occurred when humans took wild grass grains, soaked them in water, and mixed everything together, mashing it into a kind of broth-like paste. The paste was cooked by pouring it onto a flat, hot rock, resulting in a bread-like substance. Later, this paste was roasted on hot embers, which made bread-making easier, as it could now be made anytime fire was created.
Baking flourished in the Roman Empire. In about 300 BC, the pastry cook became an occupation for Romans (known as the pastillarium). This became a respected profession because pastries were considered decadent, and Romans loved festivity and celebration. Thus, pastries were often cooked especially for large banquets, and any pastry cook who could invent new types of tasty treats was highly prized. Around 1 AD, there were more than three hundred pastry chefs in Rome, and Cato wrote about how they created all sorts of diverse foods, and flourished because of those foods. Cato speaks of an enormous amount of breads; included amongst these are the libum (sacrificial cakes made with flour), placenta (groats and cress), spira (our modern day flour pretzels), scibilata (tortes), savaillum (sweet cake), and globus apherica (fritters). A great selection of these, with many different variations, different ingredients, and varied patterns, were often found at banquets and dining halls. The Romans baked bread in an oven with its own chimney, and had mills to grind grain into flour.
Eventually, because of Rome, the art of baking became known throughout Europe, and eventually spread to the eastern parts of Asia. Bakers often baked goods at home and then sold them in the streets. This scene was so common that Rembrandt illustrated a work that depicted a pastry chef selling pancakes in the streets of Germany, with children clamoring for a sample. In London, pastry chefs sold their goods from handcarts. This developed into a system of delivery of baked goods to households, and demand increased greatly as a result. In Paris, the first open-air café of baked goods was developed, and baking became an established art throughout the entire world.