Testing the Purity of Flour


Cooks in the 1840s had to worry about the purity of flour. The addition plaster of Paris, ground stones, bones, and whiting increased flour’s weight and bulk. The practice placed harmful additives in flour (making it adulterated) and deceived buyers.

According to the Free Dictionary, whiting can mean a pure white ground chalk used in putty, paints, and ink. Whiting also refers to food fishes that possess “delicate white flesh.” My guess is that the ground chalk is the whiting used by the deceptive sellers.

accident-1238326_960_720Plaster of Paris is not an innocent ingredient either. The white powder mixes with water to become a hard solid. Sculptures and casts for broken limbs contain plaster of Paris.

Sarah Josepha Hale, the author of an 1841 cookbook, believed these harmful additives were rare in the United States yet suggested testing for these undesirable flour substances.

To test for whiting, dip fingers and thumb in sweet oil (olive oil.) Then pinch a bit of flour between the oily finger and thumb and rub. If the flour is pure, it won’t turn sticky but it will darken to almost black. If whiting is present, a few rubs turn the flour to putty and the color remains white.

I tested the flour in my canister. It didn’t darken at all and clumped up. It didn’t pass Hale’s test.

Dlemons-1132558_960_720rop lemon juice or sharp vinegar on a teaspoon of flour to test for plaster of Paris or stone dust. An immediate reaction shows the presence of these additives. If there is no reaction, the flour is pure.

Another purity test is to squeeze a handful of flour tightly. If the flour stays in a lump when opening the hand, it’s pure.

Thankfully, my flour passed the tests for plaster of Paris or stone dust. I can’t explain why it didn’t pass the whiting (chalk) test. Perhaps modern manufacturing practices?

If flour has turned sour or musty, bakers will easily notice it by the smell.

Though regulations and laws protect consumers today, it’s fun to know a few of the old tips used by our ancestors to protect their families.

-Sandra Merville Hart


American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014.

Hale, Sarah Josepha. Early American Cookery: “The Good Housekeeper.” 1841, Dover Publications , Inc., 1996.