Practical milling – part 3


By Sophie Nieport

Darke County Park

Welcome back, as I continue summarizing an interesting book titled Practical Milling, published in 1924.

American millers, after adopting the automatic milling equipment, thought it best to have the stones as close as possible when grinding. This maximized the amount of flour produced and minimized the bran, or middlings. This technique was called the “American” or “Flat Grinding” Process. They found that re-ground middlings created an inferior flour. Flat grinding made the product hotter and wetter than if ground with the stones further apart. This is where the hopper boy, or cooler came into play, and the meal would be cooled down before entering the bolter. The hopper-boy spread out the meal from the stone, gradually working it to the center of the room. The meal then got fed to reels or bolters on the floor below. Hopper-boys ranged in diameter from 6 feet to 15 feet wide and would turn about 55 revolutions per minute.

A simple mill during this time consisted of one set of 4-4.5 ft. diameter stones that could grind at the rate of 20 bushels per hour, producing 100 or more barrels of flour in 24 hours. The remaining equipment in a simple mill design included a cooler, one hexagon bolter, a scourer, and two elevators.

Hard spring wheat, with brittle bran, needed to be ground higher with more space between the stones. This caused more middlings to be produced. Inventions and improvements made to purifiers were made in order to re-grind the middlings for a better product. It was found best to purify the middlings by removing impurities, then regrinding them, making ‘patent flour,’ which could be sold for almost double the amount. The first successful purifier used in the United States was in 1871 in the Washburn Mill at Minneapolis.

Flat Grinding became less desirable. “New Process Milling” involved raising the stones and grinding high became common practice. This also created a change in the way the grooves were etched into the stones. When you want finer flour and less middlings, you created more lands, or flat spots, and fewer furrows. Changing over to the New Process, less lands were made, and furrow surface increased. The rate of feeding the grain into the stones decreased from about 20 bushels an hour to 8-12 bushels per hour. The speed of the stones was also slowed down in the New Process Milling, creating less heat. Keeping the stones slow and cool was important.

Attention to the stones increased. Stone dressing became an art and a science. The surface of the stones was kept as smooth and true as possible. Various new styles of dresses were experimented with. Without guides or prior knowledge, millers had to be innovative thinkers willing to try new things. Millers wore many hats and had to have an ingenious mind. This New Process Milling was most common from 1875-1883 before steel roller mills were introduced.

The transition to roller mills in the United States was gradual until about 1881. At first, millers just used the roller mills for grinding middlings, still using stones to grind wheat. But eventually, all mills transitioned to roller mills or went out of business.

Bear’s Mill is unique for the fact that even though the mill was converted to a roller mill, the French Buhr stones were kept intact. We still have three sets of these stones, all in great condition. We only use one set for grinding due to less demand, but all three sets have life left in them. When visiting Bear’s Mill, you can travel through time and see how the mill transitioned and grew based on milling technology. We are fortunate to have all of the equipment we do, and I am honored to contribute to its continued preservation.

As we welcome 2024, join us in celebrating Bears Mill’s 175th birthday! Keep an eye out for special events, a new book and video, and fun surprises in the gift shop! Follow Historic Bear’s Mill and Darke County Parks on social media for the most up-to-date information.

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