Raising Agents

Chemical raising agents were used first around the mid-nineteenth century. A mixture of an alkali and an acid with liquid gives off the gas which raises the dough. Bicarbonate of soda (alkali) and cream of tartar (acid) were first sold separately, but later produced as a ‘baking powder’, a mixture of the two along with some kind of starch to prevent the two agents reacting with one another before use. Apart from the convenience of measuring out one spoonful rather than two or three, there is no other advantage in buying baking powder since you pay for unnecessary extra starch. Baking powder’s raising power deteriorates with age.