Baking Soda (also sodium bicarbonate) A natural chemical compound used as a cleaning agent as far back as ancient Egypt, baking soda in its current form was first made commercially available in 1846. Though it can be produced using several methods, which will affect purity, commercial quantities are created by dissolving soda ash in water and treating it with carbon dioxide. Soda ash is found in a natural mineral mined in several parts of the US and in Africa.
When baking soda is exposed to moisture and acids during the baking process, the carbon dioxide in the soda is released, which causes expansion of the batter of such items as cookies, pancakes, cakes, non-yeast (quick) breads, etc. Baking soda, once acidified, will begin to release the carbon dioxide as soon as it is exposed to moisture, so it should be added to dry ingredients and properly incorporated before combining wet ingredients, and the wet batter put in the oven right away. Acidifying agents include cream of tartar, lemon juice, yogurt, buttermilk, and vinegar, among others.
Baking soda is a major ingredient in baking powder, which contains the acidic agent as well as a drying agent, so that the carbon dioxide release is activated by the addition of moisture. If a recipe calls for baking powder and none is available, it can be made by combining one part baking soda and two parts cream of tartar (the acidifying agent).
Baking soda that is kept open in the back of the refrigerator to ‘absorb’ unpleasant odors should not be used for baking, and expiration dates matter for this product, if it’s old it will not react properly to the acidifying agent and the baked good will not rise or will only partially rise, having an unpleasant texture and density.
As an additional kitchen use, baking soda can be used to extinguish small electrical or grease fires, but only if the fire is quite small. It requires a lot of baking soda to extinguish a fire, and anytime a product is tossed onto a grease fire there is a very real risk of splattering the grease fire and spreading it instead of extinguishing it.
photo credit: grimescrubbers.com