|The Wheat Sifters by Gustave Courbet, 1855|
- Bolting is another word for sifting the flour to remove part or all of the wheat germ and bran.
- Extraction Rate: This refers to the amount of bran and germ that is removed (extracted) from the flour. For example, if you bring a miller 100 pounds of wheat in its kernel form and receive back from him 85 pounds (85%) of ground wheat flour, the extraction rate is 85% (15% of the total weight that was removed in the form of germ and bran).
- Bolting cloths: Sacks that were used to sift out the germ and bran. They were originally made of tough canvas, linen, or wool.
What were extraction rates in the past?
- Modern technology of today removes all of the bran and germ, giving modern users an extraction rate of about 72%.
- According to food historian, Peter Brears, millers in the medieval days were skilled enough to be able to extract all of the germ and bran, thus they yielded flour at an extraction rate close to today's low percentage rate, if they chose.
- However, according to another food historian, Elizabeth David, she feels that “it cannot have been possible for millers to produce flour of anything approaching the degree of fineness and whiteness we now know.”
- Similarly, food historian, Karen Hess, states that “the technology for turning the golden life-giving wheat flour of yesteryear into the chalky lifeless dust of today had not yet been perfected in the day of Mrs. Randolph [late 18th-early - early 19th c. America]. The wheat germ was still pretty much intact and even tiny flecks of bran escaped the bolting cloths, so that white flour was a lovely cream color and was more flavorful and nutritious than the flour of today.”
- The process of bolting flour changed a lot in the middle of the 18th century because of the introduction of a fine silk bolting cloth that yielded whiter flour with a higher extraction rate.
- Roller mills invented in the late 19th c. further reduced the extraction rate to about 75% because the wheat was no longer crushed by stones all together with the bran and germ. Instead, the wheat kernels were sheared open to free the endosperm (gluten-rich white) from the bran and germ; essentially the wheat kernel was stripped and left as granular semolina (think Farina/Cream of Wheat). This process heated up the the kernels and some of the nutrients were lost.
- Bleaching and Conditioning the Flour: In the Age of Industrialization, bromates were used to make the flour whiter. This process destroys the Vitamin E in the wheat. Conditioners were also used to make the flour longer-lasting and bouncier. Breads were then enriched with vitamins and minerals to counteract the depletion of them in the processing.
- In addition, according to Karen Hess, soft wheat was used most often in the American south, and flecks of bran and germ would have made the flour cream in color, and more nutritious and flavorful. FYI - the wheat that was used in the mid-west during the Homesteading days of the mid-to-late 19th c. was the hard, red wheat variety.
- Therefore, for recreating recipes in the 18th-19th c. American south, I either use a white whole-wheat pastry flour or an all-purpose flour with a bit of the wheat germ and bran added back in (about 1 Tbsp per cup).