Wheat and Its Products, by Andrew Millar, 1916
WHEN I undertook to write a short book on wheat, its habitat, its transportation, and the production from it of wheaten flour, I set two objects before me. The first was to tell in simple language, with as few technicalities as possible, whence and how the raw material is obtained and to describe the modern method of producing flour, so that my work might be of interest to all classes of readers. The manufacture of flour is now such a science, that technicalities cannot altogether be avoided in dealing with the subject; but I have tried to simplify the terms so that those who know little, or nothing, of the industry may be easily able to understand the various process through which the grain passes before pure flour is ready for the use of the housewife or baker. We read so much of the wheat fields of the United States and Canada, as also of those of India, Australia, and Argentina, that more people will be surprised to learn that more than half of the world's wheat crop is still grown in Europe. My second object has been to write a book so technically correct that it shall be both interesting and useful to millers and all others connected with the bread stuffs industry. How far I have succeeded, I must leave to the judgment of my readers. Flour milling is, even yet, in such a state of transition, and new methods and machines are so continually being introduced by milling engineers and their experts, that only by the constant study of the trade journals can millers keep themselves well informed of the latest innovation in the process of manufacture. Andrew Millar. London, March 1916.
When man first discovered the art of reducing, or grinding, wheat into meal is, like the origin of the cereal itself, quite unknown; but the oldest pictorial and other records that are discovered from time to time indicate that the art, in a crude form, was practiced by the nations of antiquity. Probably the earliest method was to pound the grain with a stone; and later a hollow stone was used as a base, and the grain pounded with a pointed stone, on the pestle and mortar system. There is evidence of this simple method being used by the Romans as late as A.D. 79. Milling is so often mentioned in the Bible, and so important was the means of reducing flour to meal considered, that the Mosaic law forbade anyone to take a millstone in pledge. The Jews certainly used two round stones, or a guern, to grind their grain, one stone being made to revolve upon the other. The earliest authentic history of milling was in Abraham's time, when he told Sarah to prepare fine meal for the angels, though it is apparent that is was, even then, an old art, and the grinding of grain was part of woman's daily work. Presumably Sarah used some sort of a sieve to make the fine meal from the ordinary meal, and we are told in the Bible of flour, fine flour, and the finest wheat flour, so that there were, apparently, sifting appliances and grades of flour even in those days, and the finest flour was doubtless reserved for the head of the family and honored guests, while the servants and slaves used the coarse meal. Egyptians doubtless advanced the art of milling, for their civilization was far ahead of that of any other country of the ancient world. In hieroglyphics, on stone, are to be found representations of grinding grain, and sifting the flour from the husk, or bran, with hand sieves. When the Israelites fled from Egypt, they doubtless carried their mills with them, as well as the kneading troughs, which are mentioned in Exodus. Manna had to be ground, for it states in Numbers xi, 8: "The people went about, and gathered it, and ground it in mills, or beat it in a mortar, and baked it in pans and made cakes of it." The art of grinding seems to have come only from the East, as there had never been found amongst the Aborigines of Australasia any trace of a grinding device. Neither is there any evidence of the American Indian having had any idea of grinding Indian corn. The quern, or hand mill, was introduced into Europe at an early date, for there is evidence that Gauls and Early Britons used them before the Roman invasion. This style of milling is estimated to have been in use for at least 4,000 years. Evidently there were inventors even in those days who tried to provide a better means of milling than the quern afforded, and a sketch of a statuette in limestone in the Cairo Museum shows a woman grinding with a roller mill over 5,000 years ago. Such a mill was recently found in the priest's house connected with the temple of the tomb of the fifth dynasty Pharaoh, Nefer-Ar-Ka-Ra (according to Professor Flinders Petrie about 3660-3680 B.C.) at Abusir. It is of red sandstone, and is now in the Berlin Museum. Unfortunately the upper stone is missing; but it appears to have been a kind of roller between which, and the smooth surface, the corn was ground, and the meal would probably be pushed into a receptacle at the end. There are two shallow half moon shaped recesses on either side of the plain surface, and these may also have been intended to receive the meal, or maybe they were for the knees of the operator to rest in. Following the quern, the slave and the cattle driven mills made their appearance. These, with continuously running stones, were probably the direct parents of the millstone, as it was known up to late in the nineteenth century, and as, indeed, it is still used for other purposes than wheat grinding. The Greeks seem to have been the inventors of power driven corn mills, and the water mill. The water mill, such as it was, appears to have been a kind of boat anchored out in the stream, the water wheel being pushed round by the natural flow of the water, and probably the stone ran very slowly. The Romans improved on this, and probably constructed the first mill dams, to obtain a head of water at one point; but there seems to be no record of the date of this invention. Public water mills are mentioned in the Roman laws of 398 B.C., but it is questionable if there were many of them at that date; and there is no evidence of power driven sifting machines. These water wheel mills were introduced into Britain by the Romans, and doubtless one was erected at each of the Roman camps. It does not appear that anyone though of building a large water wheel to drive several pairs of stones till late in the eighteenth century. In Doomsday Book hundreds of mills are mentioned, and were obviously considered to be of great value to the owner. There were very stringent laws, about that time, compelling the people to have their corn ground only at the mill of the lord of the manor. The Dutch probably built the first wind mills, and this is easily understood when it is remembered that there are few rivers in Holland, and that the country is flat, giving small fall to the rivers. It was largely owing to the latter reason that wind mills were originally so common in the fen country on the English East Coast. John Smeaton, a famous old Yorkshire millwright, introduced many improvements in mill gearing and driving. It was in a mill near Wakefield that he first introduced spur gearing, under the millstones, to drive several pairs at once from the one large spur wheel - an entirely new application of this simple device. He was also the first to advocate the use of a steam engine to drive flour mills, in a letter dated 23rd November, 1780, addressed to the British Government. The Albion Mills, London, situated near Blackfriars Bridge, are supposed to have been the first steam mills erected. Built in 1788, they were destroyed by fire a few years later. They were looked upon as a monopoly, dangerous to the public interest; but it is said that they reduced the price of flour in London. Cast iron instead of wood. Wooden shafts, both horizontal and vertical, are still to be found in the old country mills, looking like revolving trunks of forest trees. Millstones, as used for wheat grinding up to the latter part of the nineteenth century, had changed little since the third century. The upper, or runner, stone of the pair, carried on the vertical spindle, was made to rotate over the lower, or bed stone. The wheat was fed into a hole in the center of the runner and carried through between the stones by centrifugal force, assisted by the furrows cut in the faces of the stones. IT was ground on its way to the periphery, and there discharged and collected. The stone used was French Burr from quarries in Champagne, France. The name of the man who invented furrows is lost in antiquity; but some sort of dress must have been invented as soon as stones were driven mechanically, and so ran more or less continuously. To all practical purposes the millstones is out of use today, as far as wheaten flour manufacture is concerned; but it is still largely used for grinding maize, barley,. and other grains, as well as minerals and other material. In the days of the stone mill mechanical sifters were utilized for separating the bran or husk from the flour. One of the best known at one time was a wire covered cylinder, set at an angle of 45 degrees. Inside the cylinder, and fixed to a revolving shaft, were four brushes, each the length of the cylinder. The meal was collected from the stones in sacks and allowed to stand for perhaps a few days. It was then fed into the top end of the cylinder, and the revolving brushes forced the flour through the wire mesh with which the machine was covered. This machine was called a "bolter," and hence we got the word "bolt" flour, which was used up to quite a recent time when the term to "dress" flour became usual; and modern flour sifters are collectively spoken of as dressing machines here, though in America the old English name of bolter is still in common use. Following the wire covered bolter came a textile covered machine, invented by Blackmore, and called Blackmore's bolting reel. This was a hexagonal shaped reel, covered with a woven worsted cloth, and can be found still in many country mills. No force was used inside the reel, the flour being sifted through the cloth by the shaking action of the revolving reel. The old wire bolter may be said to have held the field till the introduction of silk bolting cloth from the continent, about the middle of the nineteenth century. Long hexagonal reels were than invented, and on the arms forming the reel the silk was laced tightly. This silk bolting cloth is woven one meter wide, and since it came into general use, all mill dressing reels have been built so many meters long, so that none of the silk might be cut to waste. Machines of this class are still spoken of by the number of sheets of silk that are required to clothe them from end to end. The old hexagonal reel was made six or eight sheets long; and, as the mesh of the silk was much finer than the old woven wire, the dressing of the flour, i.e., the separating of the flour from the bran, was done much more perfectly. Silk has never been superseded by any other material for sifting in modern flour milling. Sir William Fairbairn was the man who, perhaps more than any other, left his mark on flour mills of the old type. He brought millwright work to a high state of perfection. His millstone fittings, gearing, etc., were far in advance of anything that had previously been seen in any corn mills. He was responsible for the marvelous improvements that, starting earlier in the century, had removed so much of the heavy, cumbersome gearing and shafting from British mills, and replaced it with well designed and balanced appliances for transmitting power. Others, of course, followed his example, so that the latter mills of the stone period were triumphs of engineering skill. The final revolution in flour milling in England really began in 1881. Flour superior to the home made article was being poured into the country from Hungary and America. British millers began to feel that something was wrong. The talk was of rollers, and the trade papers were full of the subject. Improved dress for millstones was advocated, and tried. Diamond stone dressing machines were introduced. Some few millers had been looking into the matter; but 99 per cent, believed that only stones could grind wheat properly, in spite of the fact that Hungarian flour, which was capturing the best trade, was made on rollers. A few smooth rollers were introduced to soften middlings, which had hitherto been reduced on stones, or sold for making ships biscuits and things of that class. Purifiers were invented to extract the bran particles from the middlings, to enable them to be ground to better advantage on either stones or rollers. All this was so much time and money wasted; and yet, perhaps, not totally wasted, for all the intermediate systems were part of the evolution that led to the roller mills of today. The first roller mills appeared crude now to those who remember them. They were not automatic. Partly finished products were sacked off, and shot on the other machines to be finished, as convenient. The year 1881 will always be remembered in the trade as that of the great exhibition of improved milling machinery which was held in London. A number of complete mills were erected, and shown at work, in the Agricultural Hall at Islington. Even then, so great was the difference of pinion as to the advantage of rollers, that stone mill builders exhibited stones and stone dressing with which they undertook to extinguish the hopes of the roller mill men. The millstone, however, as a flour maker, had had its day, and had to give way to fluted iron rollers; and the roller system came like an avalanche and swept all the old methods away. At one time in the "eighties millers seemed to care less about the cost of a roller plant than the speed with which it could be installed, as their competitors who had changed their system, before them were carrying off all the trade. The country was at the same time being inundated with flour from America, whose millers said, and thought, they were going to capture the trade and put British mills out of use. The decrease in the imports of American flour of late years, and the success of roller milling, shows how the British millers fought, and defeated, the attempt to put them out of business. The full history of the evolution in the manufacturing side of flour milling during the last fifty years would require several large volumes to record it; so it must suffice to say that the essential differences between the old and new method were the introduction of the middlings purifier, and the substitution of iron rollers for stones. The dressing system is much the same in principle, though improved in detail. Milling is first and foremost, grinding. With stones the grinding was done with one operation: with rollers it is a system of graduated reduction.
Though the millstone has practically gone out of use grinding wheat, yet it is still so largely used for other branches of milling that it is worthy of consideration in connection with the craft. It is generally used for making whole wheat meal for brown bread. It is largely employed in Scotch oat meal manufacture, and for grinding barley, maize, beans peas, and other provender cereals into meal. French Stones. - Wheat and maize are always ground on French burr stones. These burrs, which come in comparatively small pieces from France, are faced up, fitted and cemented together, and then hooped with two strong iron hoops to make up the complete stone. The face is dressed down to a perfect plane. The back, which has purposely been left rough, is covered with cement to any desired thickness, and rounded towards the center. Each stone of a pair has a hole in the center, called the eye. The eye of the runner, 10 inches in diameter, while that of the stationary, or bed stone is usually 10 inches square. Otherwise the two stones are identical. The bed stone is laid on its back in a frame, called the hurst, and an iron plate carrying adjustable brass bearings is firmly fixed in the eye below the level of the face. A spindle runs up through the eye plate to a required height; its other end resting to a support below in such a way that it can be raised or lowered. On the top of the spindle is placed a driving iron, with two or three projectors which fit in sockets cut in the edge of the eye of the runner, or revolving, stone. When the stones are face to face, ready to start grinding, all the weight of the top stone rests on the driving irons, and so on the top spindle. The spindle is driven from below either by means of gear wheels or by pulleys and belt. The stones are enclosed in a circular wooden casing called the hoop, which has a hole in the center corresponding to the eye of the stone. Over this is mounted a small hopper, the bottom of which is loose and called the shoe. A rod, called the damsel, coming up from the spindle and revolving with it, has cams which strike the shoe and vibrate it, causing a stream of grain to flow into the eye of the stones. Millstones are usually 4 foot or 4 foot 6 inches in diameter, and about a foot in thickness. A 4 foot 6 inch stone runs at a speed of about 130 revolutions a minute, and a 4 foot stone at 140 to 150 revolutions. The runner is accurately balanced on the top of the spindle to ensure even grinding. the wooden casing is far enough from the stone to give good clearance all round. A sweeper, attached to the periphery of the runner, carries the meal round with it, till it reaches an opening for its discharge in the case or frame. Smooth stones would be of very little use for grinding, so various work has to be done on their faces to keep them rough, or, technically, sharp. This is spoken of as dressing the stones. The chief dress is the furrows; these are cut not redating from the eye, but each of the masters, or long furrows, is cut from a point 4 inches or 5 inches wide of the center of the eye, of the stone. It is immaterial whether a stone runs with, or against, the sun, but, if against the sun, or left handed, the master furrows lead from the other side of the eye. The face of the stone had two or three short furrows parallel to each master furrow, forming a "harp." Furrows are cut about a quarter of an inch deep at one edge, and taper away to nothing on the other. they may be 1 1/4 inch wide, and have 2 inches of "land" between them; but there is no rule, most millers having opinions of their own on this point. A 4 foot 6 inch stone has about ten master furrows, with three shorter furrows to each to form the harp. The face of the stone is kept perfectly flat for about 8 inches from the extreme edges; from there it should taper slightly towards the eye to such a degree that, when the two stones, laid face to face, touch at the periphery, there should be nearly enough space between them at the eye to admit a grain of wheat. The outer 8 inches of the face has small lines, called "cracks," cut in the lands. These should be cut, in clear and sharp, without breaking the face of the stone between them. To do this correctly on wheat stones was a sign of the highest skill in the old stone dressers art. These men boasted how many "cracks" to the inch they could put in. About twelve was the normal number, and a sharp mill bill, or pick, was necessary for the work. All the dressing is done with these tools, the workman sitting on the stone and resting his elbows on a cushion generally stuffed with bran. Only the best of steel will stand the work, and the tool has to be continually sharpened. The old stone dresser has almost passed away, and it is hard to find a miller now who really understands the job, and can do it. The Derbyshire Peak millstone is of much rougher texture than the French, and is chiefly used for provender work. It is furrowed, and dressed, and worked in the same manner as the French stone, but is quarried all in one piece and cut into shape. It is customary to shrink a couple of lion hoops on the runner for the sake of safety, in case it should split at work, but this is not absolutely necessary, and many millers run them unhoopped. When a pair of millstones of any sort have to be dressed, the runner is turned over on its back, and the faces of both stones are dressed in exactly the dame way, so that, when they are grinding, the furrows of the runner slightly cross those of the bed stone, and thus a shearing, as well as a grinding, action is obtained. It is partly for this reason that the master furrows do not radiate from the center, but from points four or five degrees wide of the center. This distance is called the draught; and the greater the draught, the more quickly the material being ground travels from the eye to the periphery. A pair of French stones require dressing once a week, a flour mill week being about 140 hours, generally. To keep the stones faces true a staff is needed. This is built up of a number of strips of mahogany, glued and bolted together to prevent warping. It is about 4 feet long by 5 inches by 3 inches and one 3 inch face is kept dead true by testing it on, and adjusting it to, an iron proof staff. The true face of the wooden staff is lightly painted with a water paint. It is then rubbed over the face of the stone, or rather, on the skirt, or 8 inch wide circle of the face nearest the periphery, when any unevenness is at once marked by the paint, and must be dressed down as needed. If any part of the stone between the eye and the skirt is marked, it must be dressed off till the staff clears it. Furrow strips are flat strips of wood, one the width of the furrows and the other the width of the "lands" between. These are used as rulers to mark the furrows, which are then dressed down to keep them to the correct width and depth. On French stones, the wear is infinitesimal, but the face soon wears too smooth to grind freely, and needs sharpening every week by "cracking" the skirt, and dressing the smooth face off the rest of the stone and the furrows, by lightly chipping with a sharp mill bill. It is considered a good day's work (10 1/2 hours) for a stone man to dress one wheat stone. In the latter days of stone milling mechanical stone dressers were introduced, diamonds being used to cut or dress the stones, instead of the steel mill bill used by hand. They met with a certain amount of success, but the day of the millstone had nearly passed by then, and they were too delicate for the coarser dressing required for provender milling. Within the last few years, composition millstones have superseded the old fashioned, built up French stones. These are made from ground French burr, mixed up with cement, in the same manner as concrete, and rammed into moulds to form the millstones. Sometimes emery is used instead of French burr. The advantages of the composition stone are: First, and most important, that the face, formed of small pieces, does not glaze, and so always keeps sharp; the only dressed necessary being a periodical deepening of the furrows. Second, a more even grit is obtained. High speed mills, fitted with small diameter stones, are largely used for grinding various cereals, and especially for reducing the screenings, from the wheat cleaning department of flour mills, to fine meal for mixing into wheaten offals. Maize. - Besides being ground on French burr, maize is often reduced on other types of machines. A great deal of this grain is used in distilleries, and is often ground on a three pair high roller mill. The rollers are fluted, and the material having been broken down on the top pair, falls direct to the second of further reduction, and then to the third pair for finishing. Another type of machine is the high speed disc mill which grinds chiefly by percussion: the fluted, chilled iron discs revolving in opposite direction, and not actually coming in contact with each other, even when no grain is passing through. Another type is the disintegrator (hammer mill), which consists of beaters revolving inside a chamber at a very high speed, and reducing the grain entirely by percussion. Maize is never required be ground into a fine, soft meal as are most other cereals. Barley. - Barley was generally ground on Derbyshire Peak stones, because the coarseness and sharpness of the grit of these stones cut up the husk better than any other. Since their introduction, composition stones have been keen competitors of Peak stones. Barley is required to be ground to a fine, soft meal, and the husks must be well ground to obtain this. It is not unusual for millers to sift the coarsest of the husks out of the meal and return them, continuously, to the stone with the barley being ground, so that they may be reground two or three times till enough to pass through the mesh of the sifter. Peal barley is produced by scouring the husk off the berry and leaving the endosperm unbroken. This is accomplished by means of a Peak stone revolving on a spindle in a cage made of stout, closely woven wire, the grain being scoured against the wire by the stone. Oats. - Oats are ground for poultry feeding in much the same way as barley. For making Scotch or Irish oat meal, the corn is first thoroughly dried on a kiln. It is then run through a pair of Peak stones; the runner being raised from the bed stone to a sufficient height to only scour the oats and not grind them. By this means the hulls are rubbed off the oats, and are then removed by winnowing. The groats are then ground into meal of the required coarseness, either on millstones or on metal mill of various types. The chief difficulty was to scour the oats sufficiently to remove the hulls without damaging the grains that parted with their hulls first and most easily. Machines have now been introduced to separate hulled and unhulled oats, the latter being sent back for further scouring, while the former are passed on to be reduced to meal.
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