Baking is cooking food in an oven with dry heat applied evenly throughout the oven and is synonymous with roasting. Although it is common in some cultures to use the term baking for the so-called baked-goods, such as breads, cakes and pastries, and 'roasting' for other foods, such as meats and vegetables, the terms can also be used interchangeably.
The dry heat of baking causes the outside of the food to brown or char, giving it an attractive appearance and pleasing taste. The browning is caused by caramelization of sugars and is the result of the Maillard reaction. Despite common misconceptions about the browning process, moisture is never entirely sealed into the food. Over time an item being baked will continue to lose moisture. This can be an advantage, especially in situations where drying is the desired outcome, for example in drying herbs or in roasting certain types of vegetables. Where drying is not desired, a protective layer of butter, oil, or, in the case of breads and pastries, egg wash, can slow the loss of moisture as well as providing flavor and additional browning. Alternatively, some foods are replenished with moisture during baking by placing a small amount of liquid (such as water or broth) in the bottom of the pan and letting it steam up into or around the food.