Also Known as Sodium Hydrogen Carbonate or Sodium Bicarbonate
What is Baking Soda?
Baking soda is usually used in batter or dough systems, like cakes and cookies, to provide leavening. It releases carbon dioxide when it comes into contact with acids and water, thus expanding doughs and batters to produce baked products with a porous structure. It is an economical, non-toxic, and easy-to-handle ingredient that doesn’t give an off flavor in the end product.
Baking soda can be produced by the reaction of carbon dioxide with an aqueous solution of sodium hydroxide, or by treating a sodium carbonate solution with carbon dioxide. It can also be prepared by the Solvay process, which is the reaction of sodium chloride, ammonia, and carbon dioxide in water. However, the product from the Solvay process is low in purity.
Baking soda or sodium bicarbonate is high in sodium.
Baking soda reacts with acids and water to create carbon dioxide. In cakes, cookies, biscuits, crackers, and quick breads, it is used to leaven dough and batters. In situations where water and acidic compounds are available, the sodium bicarbonate reacts with the acid, liberating carbon dioxide. It then decomposes to the sodium salt and water molecules. The optimal reaction is shown as follows: NaHCO3 + H+ = Na+ + CO2 + H2O.
In dough, baking soda can exist as free CO2 or in one- or two-ion forms, HCO3- or CO32-. At pH <5, nearly all bicarbonate in the dough is dissociated into the leavening gas CO2. At a pH between 5 and 8, only part of the CO2 is in the gaseous state. No leavening gas is available at pH>8.1
Baking soda is the main ingredient in baking powder, which is a combination of baking soda, leavening acids and an inert starch.
Many soft wheat dough products have a final pH of around 7, so if significant quantities of gas are to be obtained, the dough must contain acid components that lower pH. If the formula doesn’t contain acid, a combination of baking soda and an acid (i.e., baking powder, monocalcium phosphate, or cream of tartar, the monopotassium salt of tartaric acid) should be used.1
For cakes, baking soda should be used in conjunction with one or more leavening acids to produce the desired reaction rate and finished pH. For cookies and crackers, baking soda will be added at 0.5%–1% of the flour weight. Baking soda should be dry-blended with the flour.
In cookies, a pH of 7±0.5 is also targeted due to the effect of excessive baking soda. When too much baking soda is used, the cookie will yield a yellowish crumb and an unpleasant soapy taste.2
Baking soda is high in sodium. For low-sodium applications, potassium bicarbonate may be substituted.
Baking soda is GRAS and is regulated by the FDA in article 21CFR184.1736 in the Code of Federal Regulations.3 The FDA also regulated baking soda labeling in 2001 by changing the reference amount from 1 gram to 0.6 gram.4
- Belderok, B., et al. “6. Manufacturing of Other Wheat Products.” Bread-Making Quality of Wheat: A Century of Breeding in Europe, Springer Netherlands, 2000, pp. 47–48.
- Sumnu, S.G., et al. “Chemical reactions in the processing of soft wheat products.” Food Engineering Aspects of Baking Sweet Goods, CRC Press, 2008, pp. 52–54.
- U.S. Food & Drug Administration. “21CFR184.1736 – Code of Federal Regulations Title 21.” Accessdata.fda.gov, 1 Apr. 2017, www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=184.1736. Accessed 7 Sept. 2017.
- U.S. Food & Drug Administration. “Guidance for Industry: Food Labeling – Serving Sizes Reference Amount for Baking Powder, Baking Soda, Pectin; Small Entity Compliance Guide.” U S Food and Drug Administration Home Page, Center for Food Safety and Applied Nutrition, July 2001, www.fda.gov/RegulatoryInformation/Guidances/ucm063136.htm. Accessed 7 Sept. 2017.