Baking, process of cooking by dry heat, especially in some kind of oven. It is probably the oldest cooking method. Bakery products, which include bread, rolls, cookies, pies, pastries, and muffins, are usually prepared from flour or meal derived from some form of grain. Bread, already a common staple in prehistoric times, provides many nutrients in the human diet.

History
The earliest processing of cereal grains probably involved parching or dry roasting of collected grain seeds. Flavour, texture, and digestibility were later improved by cooking whole or broken grains with water, forming gruel or porridge. It was a short step to the baking of a layer of viscous gruel on a hot stone, producing primitive flat bread. More sophisticated versions of flat bread include the Mexican tortilla, made of processed corn, and the chapati of India, usually made of wheat.
Baking techniques improved with the development of an enclosed baking utensil and then of ovens, making possible thicker baked cakes or loaves. The phenomenon of fermentation, with the resultant lightening of the loaf structure and development of appealing flavours, was probably first observed when doughs or gruels, held for several hours before baking, exhibited spoilage caused by yeasts. Some of the effects of the microbiologically induced changes were regarded as desirable, and a gradual acquisition of control over the process led to traditional methods for making leavened bread loaves. Early baked products were made of mixed seeds with a predominance of barley, but wheat flour, because of its superior response to fermentation, eventually became the preferred cereal among the various cultural groups sufficiently advanced in culinary techniques to make leavened bread.

Brewing and baking were closely connected in early civilizations. Fermentation of a thick gruel resulted in a dough suitable for baking; a thinner mash produced a kind of beer. Both techniques required knowledge of the “mysteries” of fermentation and a supply of grain. Increasing knowledge and experience taught the artisans in the baking and brewing trades that barley was best suited to brewing, while wheat was best for baking.
By 2600 BCE the Egyptians, credited with the first intentional use of leavening, were making bread by methods similar in principle to those of today. They maintained stocks of sour dough, a crude culture of desirable fermentation organisms, and used portions of this material to inoculate fresh doughs. With doughs made by mixing flour, water, salt, and leaven, the Egyptian baking industry eventually developed more than 50 varieties of bread, varying the shape and using such flavouring materials as poppyseed, sesame, and camphor. Samples found in tombs are flatter and coarser than modern bread.

The Egyptians developed the first ovens. The earliest known examples are cylindrical vessels made of baked Nile clay, tapered at the top to give a cone shape and divided inside by a horizontal shelflike partition. The lower section is the firebox, the upper section is the baking chamber. The pieces of dough were placed in the baking chamber through a hole provided in the top.
In the first two or three centuries after the founding of Rome, baking remained a domestic skill with few changes in equipment or processing methods. According to Pliny the Elder, there were no bakers in Rome until the middle of the 2nd century BCE. As well-to-do families increased, women wishing to avoid frequent and tedious bread making began to patronize professional bakers, usually freed slaves. Loaves molded by hand into a spheroidal shape, generally weighing about a pound, were baked in a beehive-shaped oven fired by wood. 

Although Roman professional bakers introduced technological improvements, many were of minor importance, and some were essentially reintroductions of earlier developments. The first mechanical dough mixer, attributed to Marcus Virgilius Euryasaces, a freed slave of Greek origin, consisted of a large stone basin in which wooden paddles, powered by a horse or donkey walking in circles, kneaded the dough mixture of flour, leaven, and water.
Guilds formed by the miller-bakers of Rome became institutionalized. During the 2nd century CE, under the Flavians, they were organized into a “college” with work rules and regulations prescribed by government officials. The trade eventually became obligatory and hereditary, and the baker became a kind of civil servant with limited freedom of action.

During the early Middle Ages, baking technology advances of preceding centuries disappeared, and bakers reverted to mechanical devices used by the ancient Egyptians and to more backward practices. But in the later Middle Ages the institution of guilds was revived and expanded. Several years of apprenticeship were necessary before an applicant was admitted to the guild; often an intermediate status as journeyman intervened between apprenticeship and full membership (master). The rise of the bakers’ guilds reflected significant advances in technique. A 13th-century French writer named 20 varieties of bread varying in shape, flavourings, preparation method, and quality of the meal used. Guild regulations strictly governed size and quality. But outside the cities bread was usually baked in the home. In medieval England rye was the main ingredient of bread consumed by the poor; it was frequently diluted with meal made from other cereals or leguminous seeds. Not until about 1865 did the cost of white bread in England drop below brown bread.

At that time improvements in baking technology began to accelerate rapidly, owing to the higher level of technology generally. Ingredients of greater purity and improved functional qualities were developed, along with equipment reducing the need for individual skill and eliminating hand manipulation of bread doughs. Automation of mixing, transferring, shaping, fermentation, and baking processes began to replace batch processing with continuous operations. The enrichment of bread and other bakery foods with vitamins and minerals was a major accomplishment of the mid-20th-century baking industry.

Ingredients
Flour, water, and leavening agents are the ingredients primarily responsible for the characteristic appearance, texture, and flavour of most bakery products. Eggs, milk, salt, shortening, and sugar are effective in modifying these qualities.
Liquids
Water is the liquid most commonly added to doughs. Milk is usually added to commercial preparations in dried form, and any moisture added in the form of eggs and butter is usually minimal. Water is not merely a diluent or inert constituent; it affects every aspect of the finished product, and careful adjustment of the amount of liquid is essential to make the dough or batter adaptable to the processing method. If dough is too wet, it will stick to equipment and have poor response to shaping and transfer operations; if too dry, it will not shape or leaven properly.