All-purpose flour is the foundation of many homemade cakes, breads, and pizzas, but did you know that each carefully measured cup of the snow-white wheat contains bleach?
Turning fields of golden grain into flour seems straightforward, but in order to get commercial flour to the proper fineness, gluten content, color, and texture, the wheat must go through a 70-step process that moves it through separators, aspirators (to suck up the dirt), a washer stone, and rollers. The initial steps of white flour production are strictly mechanical, but once the brand is separated from the endosperm, modern millers rely on the use of chemicals to complete the process.
It may seem counterintuitive, but freshly milled flour is not very good for baking. In order to develop the proper gluten structure, the flour must first be oxidized. Before the advent of modern chemicals, freshly milled flour would be stored for three months in order for natural oxidation to occur. (If this were still the case, the long storage period would limit the available supply and raise the price of flour and other baked goods.)
In the 1920s, millers discovered that a small puff of chlorine, the same stuff used to bleach floors and make PVC pipes, could complete the oxidation process in seconds. In addition to oxidizing the flour, the chlorine also makes the flour white and balances the acid level — making the flour more alkaline. Oxidation changes the protein structure of the flour by taming the gluten, which allows bakers to create soft and crumby cakes with a high sugar to flour ratio. If trying to avoid bleached flour, be especially wary of soft baked goods such as cakes, white breads, muffins, and tortillas.
While it’s true that chlorine is added to many brands of white flour, eating two slices of Wonder Bread is of course not the same thing as downing a shot of bleach. The flour industry uses only a small amount of chlorine, around 25 parts per million, but this is still six times more than the amount used to chlorinate drinking water. It’s important to note, however, that the difference between chlorinating water and chlorinating flour is that the former benefits the health of the general public and the latter only results in lower prices for flour. Ever wonder how McDonald’s and Taco Bell can charge only a dollar for their burgers and burritos? Their hamburger buns and tortillas all use bleached white flour.