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Baking Powder's Harvard Pedigree

May 1, 2012

They say that "you are what you eat," so all of us should be chemists by now. Although everything is chemical, we tend to think of food in a different sense, and we're concerned about the other chemicals that are added to food. Aside from specific additive and contaminant scares, such as cyclamates and certain chemical residues, our food supply is rather safe; perhaps safer, if you refrain from fatty and hormone-saturated meat.

The US Food and Drug Administration (FDA) oversees food safety in the United States. They even go as far as to impound Swiss cheese that's augmented by drilling more holes than those produced by natural aging. On the other hand, the simulacrum called "cheese food" is still allowed into our homes and gullets. Nevertheless, the FDA is one of the few federal agencies for which taxpayer dollars are well spent.

When I was in high school, we were required to read muckraking author Upton Sinclair's novel, "The Jungle," which included some vivid stories of food adulteration at the turn of the twentieth century. This book helped to launch the Pure Food and Drug Act of 1906, enforced by the US Department of Agriculture. The Food, Drug, and Insecticide agency was founded in 1927, and it was renamed the Food and Drug Administration in 1930.

Davis brand baking powder (photo by author) Nearly every household has a container of baking powder, but few know anything about this chemical mixture, other than its use in baking.

The function of baking powder is quite simple. It releases
carbon dioxide gas to increase the volume and lessen the density of baked goods; that is, it acts as a leavening agent. I wrote about baking powder in a different context in a recent article (Bubble Rockets, February 13, 2012).

Baking powder is typically a mixture of baking soda (
sodium bicarbonate, NaHCO3) and an acid salt in a starch base. The starch is there to prevent too fast a reaction. The reaction is simply given as
NaHCO3 + H+ -> Na+ + CO2 + H2O

The baking powder found in my pantry, as shown in the photograph, is labeled as "Double Acting." Double-acting baking powder is the most common type of baking powder. It contains two acid salts, one of which reacts immediately upon exposure to water, and another that reacts only at the high temperatures found in the baking oven.

Cream of tartar (potassium bitartrate, KC4H5O6) and monocalcium phosphate (CaH4P2O8) are the usual low temperature acid salts.[1] The Davis baking powder pictured uses monocalcium phosphate as the low temperature acid salt, and sodium aluminum sulfate as the high temperature acid salt.

The inventor of the first useful baking powder was Harvard chemist Eben Norton Horsford, who was the Rumford Professor of the Application of Science to the Useful Arts.[2-3] His professorship was named in honor of the American physicist, Benjamin Thompson, also known as Count Rumford. Thompson is best known for his experiments that demonstrated the mechanical equivalent of heat.

Harvard Chemist, Eben Norton Horsford

Eben Norton Horsford

From his dress, we can surmise that the Harvard classrooms were somewhat chilly.

Boston had a record low temperature of -12°F (-24.4°C) in 1951. I wasn't able to find temperature data for Horsford's era.

(Via Wikimedia Commons))

Horsford was a student of German chemist Justus von Liebig, and he became one of the first faculty members of what would become Harvard's School of Engineering and Applied Sciences. Among his technical contributions was his recommendation of the best metal for Boston's water pipes, a suitable food ration for Union troops in the US Civil War, and a process for the manufacture of condensed milk that was sold to the Borden company.[2-3]

In 1854, Horsford found that monocalcium phosphate and sodium bicarbonate was effective combination of chemicals, and in 1869 he improved his formula by the addition of corn starch. Thus, 1869 can be considered to date of the invention of modern baking powder. Horsford and George Wilson established the Rumford Chemical Works in East Providence, Rhode Island. Rumford Baking Powder is still sold today.[2-3]

In 2006, the American Chemical Society designated the Rumford Chemical Works' East Providence, Rhode Island, site a National Historic Chemical Landmark for the "Development of Baking Powder."[2-3]


  1. Baking Powder page on Wikipedia.
  2. Alvin Powell, "Bubble, bubble, without toil or trouble," Harvard News Office Article, April 5, 2012.
  3. Alvin Powell, "Bubble, bubble, without toil or trouble," Harvard Gazette, April 5, 2012.

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