Does Bread Really Contain Plaster Of Paris?

Posted by Eric Troy on 03 Jun 2014 14:35

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As far back as 1915, headlines were ablaze with the shocking news: Commercial bread bakers were putting Plaster of Paris, otherwise known as gypsum or anhydrate, into their bread doughs. It caused a controversy and investigation in Boston, New York, and other cities, during this time. Was it true? Yes. Plaster of Paris is otherwise known as calcium sulfate. It was used as a dough strengthener, and as food for yeast. It was also claimed to fortify white bread, which was devoid of nutrients.

Specifically, the allegations centered on the Ward Baking Company, which made Tip-Top Bread. William B. Ward also formed the Continental Baking Company, which made Wonder Bread and Hostess Cakes. See the related article Which Came First, the Toaster or Sliced Bread?

A Boston Department of Health official, a "Dr. Jordan," claimed that the Ward Company was making bread which contained over 60 percent mineral matter. The idea that the bread was more mineral than flour created quite an uproar.1

According to The National Baker, Volume 20 (1915) several newspaper articles on the subject gave the following formula of the bread dough recipe:

  • Calcium Sulfate (i.e. "plaster of paris") — 24%
  • Sodium Chloride (salt) — 24.9%
  • Ammonium chloride — 11.6%
  • Flour — 39.5%

That would be one hard loaf of extra salty bread if this were the true dough recipe. But, in fact, this was the formula for a dough improver powder called Arkady flour that was added in the proportion of four pounds to a 1600 pound dough batch, so that, in reality, very small amounts of the additives were actually in the bread.

According to the Boston Board of Health, the "plaster of Paris" powder samples obtained contained:

  • Calcium sulfate — 24%
  • Sodium chloride — 24.9%
  • Ammonium chloride — 11.5%
  • Starch — 30%

Although it does seem strange to have an ingredient used in casts, building materials, desiccants, dentistry impressions, etc. also used in bread doughs, keep in mind that these are minerals needed in human nutrition, and the name used for things differ according to their application. Specifically, calcium sulfate is the calcium salt of sulfuric acid. When in the form of Plaster of Paris, calcium sulfate it is in its hemihydrate form, meaning there is one molecule of water for every two molecules of the calcium sulfate. Gypsum is the dihydrate form, meaning there are two molecules of water for every molecule of the compound. When used as a desiccant, gypsum is dehydrated in electric ovens to form the anhydrous compound.


Calcium Sulfate Hemihydrate a.k.a. "Plaster of Paris"


Calcium Sulfate Hemihydrate a.k.a. "Plaster of Paris"

Although it has been used since ancient times, such as in the coagulation of soy milk to make tofu, and to stiffen bread dough and make it less sticky, it was not officially approved for use in the United States as a food additive until 1980. Flour low in calcium is very hard to use for large scale bread baking operations and calcium sulfate is used per regulation as a dough conditioner in parts not higher than 1.3%. It is also used as an anti-caking agent and as a leavening agent, and for this purpose it is found in some baking powders, such as Calumet brand. It has many other uses in foods.

Calcium sulfate, besides its use in bread and other baked products, is used in grain and pasta products; some cheeses, including soy cheeses; jams and jellies as a stabilizer and thickener; candies and frostings; processed vegetable products as a firming agent; and other foods.

Plaster of Paris was not the only 'adulteration' or additive reported to have been used. In England, during the industrial revolution, bread makers were accused of using many adulterants to bulk up their breads, such as chalk, sawdust, bonemeal, bonemeal mixed with slaugtherhouse waste, and even alum, a toxic chemical used for dying fabrics and tannning leather.

See also Food Adulteration in the 1800's.

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