Baking soda is a white crystalline powder (NaHCO3) better known to chemists as sodium bicarbonate, bicarbonate of soda, sodium hydrogen carbonate, or sodium acid carbonate. It is classified as an acid salt, formed by combining an acid (carbonic) and a base (sodium hydroxide), and it reacts with other chemicals as a mild alkali. At temperatures above 300 degrees Fahrenheit (149 degrees Celsius), baking soda decomposes into sodium carbonate (a more stable substance), water, and carbon dioxide.
Sodium bicarbonate was discovered by two workers at a college of medicine in Berlin in the year 1800. At the time there was a lot of interest in the properties and behaviour of what was called 'fixed air' (carbon dioxide). This strange material generated the bubbles in fermenting beer mash, could be made by adding acid to soda (sodium carbonate) or pearl ash (potassium carbonate), and was somehow made in the lungs of animals from the component in ordinary air, oxygen.
Imported from England, baking soda was first used in America during colonial times, but it was not produced in the United States until 1839. In 1846, Austin Church, a Connecticut physician, and John Dwight, a farmer from Massachusetts, established a factory in New York to manufacture baking soda. Dr. Church's son, John, owned a mill called the Vulcan Spice Mills. Vulcan, the Roman god of forge and fire, was represented by an arm and hammer, and the new baking soda company adopted the arm and hammer logo as its own. Today, the Arm & Hammer brand of baking soda is among the most widely recognized brand names.