History of milling technology

by Meyer Sosland
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What began as a laborious hand operation in ancient times evolved into a highly-mechanized process

by Bryan McGee

Editor’s note: This is the first in a three-part series on the history of milling technology. This article examines the evolution of wheat milling technology through the 19th century.

The history of milling technology has been one of continuous innovation in pursuit of technical and commercial improvement. Significant changes have occurred periodically, but even between technological advances, seldom has there been stagnation. To this day, cereal milling and cereal science remain full of promise.

In prehistoric times, milling of wheat into flour was a domestic activity producing the immediate requirements for the family or tribe. Wheat evolved from wild grasses in the eastern Mediterranean, Near East and Middle East region. It is thought that the first domestication took place between 10,000 and 15,000 B.C., in the hilly upper reaches of the Tigris-Euphrates drainage basin known as the "Fertile Crescent."

Man thus gained a highly nutritious food that provided a comparatively good source of protein, carbohydrate of useful glycemic index and fiber from the crudely milled flour.

Initially, milling was a laborious hand operation. That changed when animals were harnessed to provide the motive power. However, mechanization of the milling process started earlier than first thought. In Asia, the Chinese were very early users of water to power milling equipment, and recent studies of the remains of a Roman water-powered milling complex in Arles, France have shown that this plant was producing several tonnes of flour per day in the fourth century.

After the Neolithic period, simple grain pounding gave way to more efficient grinding by a rubbing action in a form of saddle quern. The process was further improved by the addition of a hopper in the upper stone and by herring-bone grooves in the lower stone.

The transition from these simple, oscillating forms to a true rotary mill, in which the upper discoidal millstone revolves upon a lower stationary stone, is not obvious. But it opened the way to much higher capacities and the move from domestic to more communitybased production. An advanced form of early grinding was excavated in Pompeii, Italy, suggesting that comparatively sophisticated conical mills were already well established in the first century. It is not clear whether the spread of these ideas was due to simultaneous invention in the East and West, or by diffusion.

The power to operate such mills soon exceeded the strength of man. Thus, animals and water were harnessed, followed in more recent eras by steam and electricity. A Roman fortress in Saalburg, Germany, abandoned in the third century, exploited mechanical advantage by means of iron shafts and lantern gears for an animal-powered mill. In China, the evidence suggests that water power was already in use and may have predated animal power in that region.

Once grinding had become established, the next logical step was to find a means of separating the finer, more palatable components from the coarser ones, which could then be reground or discarded.

It is probable that once again the Chinese, who were able to weave silk in a fine mesh, were at the forefront. There is evidence that the sieving of powders for human consumption was practiced in China before such processing began in the West. Initially, treadle machines operated by manpower were used to oscillate the sieving screen. In the 14th century, there were already references to mechanizing the process by coupling such oscillating sifters to water-wheels.

Although the 18th century Industrial Revolution in Europe stimulated many of the major advances we still see today, it was late in the Renaissance (13th to 15th centuries) that mechanisms and devices had been invented that laid the foundation for the true industrialization that followed. The move from stone milling to grinding with iron rolls marked the transition of milling to a truly technology-based industry.

Advances in milling technology have moved in parallel with those in mechanical engineering, right up to the present day when computer-aided engineering has the largest influence on the current design and manufacturing of most milling equipment.

There have been so many individual entrepreneurs and innovators with regard to milling technology that it is not easy to highlight more than a handful. To provide an example of the greatness that has gone before us, I will mention a couple of people whose groundwork has most influenced my career.

It is appropriate to mention Heinrich (Henry) Simon, who had a huge influence on the implementation and dissemination of milling technology. He was born in Silesia to a distinguished German family, gained his engineering education in Zurich, Switzerland and then settled in Manchester, England in 1860. He died in 1899, having become a leading citizen in that great city of industrial innovation.

Glyn Jones, in his 2001 book, "The Millers," wrote: "Simon was on the other side of the obvious divide between millers and engineers, which somehow had to be bridged by combinations of evident knowledge and experience together with a vital intangible: insight. Simon was receptive to new technical ideas down to the level of mechanical engineering detail. His whole enterprise depended on continuous engineering development work, linking design to practice, as milling systems were improved and scaled up."

Simon, with his network of contacts across Europe, brought together the leading ideas of his time to create a world-class company. His introduction of the roller mill-based milling system completely revolutionized the industry in Britain and its overseas dependencies, which enabled it to stem the flow of low-cost, highquality flour being brought in from the mills in the wheat belt of North America.

He was a contemporary of Adolf Buhler (1822-1896), founder of Switzerland-based Buhler AG, with whom he cooperated for manufacture of several machines. This was the age of entrepreneurial engineers who oversaw the great changes in technology during a period of equally significant social changes.

On the other side of the world, another distinguished engineer with a thirst for knowledge, Riichi Satake, became aware of rice processing developments in Burma using machines made by Messrs Douglas & Grant of Fife, Scotland, presumably adapted from their oat hulling designs.

It is thought this awareness prompted him to develop the first power-driven rice hulling and polishing machines in Japan and to found the company — Satake Corp. — which bears his name, in 1896.

Maize degermining technology has also been recently revolutionized by the application of other equipment originally developed for rice processing. Such is the benefit of cross fertilization between sectors and across international regions.

It was during the Renaissance that a fascination grew for mechanisms and devices. In 1588, Agostino Ramelli was credited with developing the first conical cylinder rotor rotating within a conical shell grind grain. But the principle had probably already been in use for half a century.

However, it wasn’t until the early 18th century that parallel cylindrical rollers were first recorded in England. About 60 years later, G. Sawlinson introduced a frame in which grains were first crushed on iron rollers and then passed through a sieving stage before being ground on stone rollers.

It was the 19th century, however, that really marked the development of practical advances and the widespread industrialization of milling. In 1834, Jacob Sulzberger, an engineer from Zurich, was the first to make the roller frame truly useful. He introduced the differential speed facility for the pair of rolls, therefore improving on a design initially manufactured by von Mueller.

Sulzberger frames were introduced into a number of mills across Europe, including the "Jozsef " mill in Pest, Germany. It was the maintenance shop belonging to this mill that in 1842 became the genesis of the famous Budapest, Hungary-based milling engineering company, Ganz.

Hard cast iron rolls were manufactured by Ransomes & Co. in Ipswich, U.K. as early as 1843 and were also introduced in 1850 by Ganz, which was experienced in producing railway wheels from hard cast iron.

It became increasingly clear that these rolls provided a benefit when compared with flat stones. With rolls, the contact distance was short — just a single line of contact — providing far cleaner and more precisely controlled opening up of the kernels and scraping of endosperm from the bran layers.

Friedrich Wegmann introduced machines with porcelain rolls in 1873 and manufacture was initially carried out by Daverio, Sievert & Gisker, near Zurich, Switzerland. Soon after he introduced his machines to Hungary, Wegmann met Andreas Mechwart of Ganz. As a result of their collaboration, Mechwart produced by 1880 a roller mill with iron rolls. His basic principles survived for the following century, especially his double roller mill that he created in 1885.

It wasn’t until after World War II that a U.S. foundry developed the "Evenchill" process that enabled the centrifugal casting of bi-metal rolls. An outer layer of hard alloy allowed for longer roll life, while the core consisted of a softer iron for ease of machining.

Thus, the Ganz roller mill can be considered the initiator of the modern roller mill, which revolutionized the entire milling industry. A development of similar importance that occurred at this time was the "state-of-the-art" machine from G. Luther of Braunsweig, Germany, which was totally enclosed and housed two pairs of rolls disposed horizontally.

Various configurations of the roller mill evolved over the course of the following century, but it is interesting to note that all designs currently in production by the major suppliers have reverted to the earlier horizontal disposition.

Contrary to common belief, Wegmann was not the first to introduce intermediate sieving. It was Gustav Adolf Buchholz, who around 1870 designed several plants in England and Hanover, Germany with several stages of roller mills interspersed with sieving of the ground stock. Buchholz was born in Berlin, Germany but spent most of his career in England, where he was the author of more than 16 patents in milling technology. WG

Bryan McGee, a milling industry consultant and former special projects consultant for Satake Corp., may be contacted at bryan@bcmcgee.co.uk.

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