Bread is a popular food in almost all the countries of the world. Its ingredients vary from country to country. In most of the countries, however, bread is made from wheat or rye flour. In some other places it is also made from rice, barley, potatoes, peas and beans.
According to the recorded history, the making of bread was started around 3000 B.C. in Egypt. Yeast was also discovered there only. Nowadays the common bread is made from dough prepared by kneading flour with water. A little yeast, sugar and salt are added to it. The yeast causes the dough to rise by forming bubbles of carbon dioxide gas in the dough. The dough is then formed into the shape of a loaf and baked in a loaf tin in the oven. In the process of baking the gaseous bubbles burst resulting in small pores inside the bread. It is mainly the yeast which gives the bread its taste and flavour. You can see these pores very easily in any bread piece.
Cakes also have pores in them, but they are produced by the baking soda and not by the yeast. Baking soda, which is the mixture of tartaric acid and sodium bicarbonate, is used in the preparation of cakes. When this mixture is added to the dough and it is baked, carbon dioxide is produced. The bubbles of this gas burst on baking causing small pores.