Baking is the process of cooking food in an oven or an enclosed baking vessel. It is probably the oldest cooking method. People have been baking bread for thousands of years. Bread and other baking products are usually prepared from wheat flour or another kind of meal (ground seeds from grains such as oats, corn, or barley).
Most 
baking products are made with flour, water, and a leavening agent. Other common ingredients in baked goods are oils, eggs, milk, and sweeteners, such as sugar.
Leavening agents are substances that cause dough or batter to rise. They do that by producing gas bubbles. These agents include yeast, baking powder, and baking soda. Yeast is often used in baking bread. Yeast is a kind of fungus. When it feeds on sugar it produces a gas called carbon dioxide. Layer cakes, cookies, biscuits, and many other bakery products are leavened by baking soda. The baking soda reacts with acids in ingredients such as milk, lemon juice, vinegar, and honey to form bubbles of carbon dioxide.
Fats and oils are ingredients in nearly all baked goods. They make it easier to work with the dough and often add flavor. The most common oils used in baking are vegetable oils. Other oils include peanut and coconut oils. Fats that come from other ingredients include egg yolks, chocolate, and nut butters.
The ancient Egyptians are the first people known to have used leavening agents on purpose. By 2600 bce the Egyptians were baking breads using methods similar to those used today. They made their doughs by mixing flour, water, salt, and leaven. They developed more than 50 kinds of bread and used different flavoring materials such as poppyseed and sesame.
Professional baking developed around the mid-100s bce in ancient Rome. The first mechanical dough mixer was introduced in Rome. Flour, water, and the leavening agent were mixed in a large stone basin by wooden paddles that were moved by a horse or donkey walking in circles.
Eventually, groups of skilled workers formed baking guilds. Over the centuries, advancements in technology brought many improvements in baking. Mixing, shaping, and other baking processes became automated. That made it easier and faster to make large amounts of baked foods in bakeries and factories. Today many people still enjoy making their own breads, cakes, and cookies at home for everyday meals or for special occasions.
