John Stevenson-building a granary-rescuingthepast.co.uk

The design and explanation of this granary by Stevenson is a very important piece of farm history. Up to the mid eighteenth century, corn yields, not especially heavy per acre, warranted storage to a depth of two feet on the the granary floor and often more when stored in the correct manner. Stevenson's granary, a little simialar to a French design, (which had louvres) enabled farmers to store more grain for longer periods. Good harvests required correct storage of the grain for longer periods, which paid good premiums, especially for bread wheat.

“A granary or magazine should not be built in a confined situation, as, near the shade or shelter of trees or buildings, but where the opposite east or west sides of such granary may be properly exposed to those points: in which case most of the intermediate points between them and the north and south, will act upon the granary more or less, according to the velocity of the wind, by fixing the folding doors thereof properly, at such times when the corn is to be ventilated.

Elevation: The granary or magazine to be built of brick or stone, of various dimensions, according to the occasions of the owner; but here as a speciman only 46 feet long by 17 broard, from out to out.

The garret, (roof space) all in one chamber, into which the corn may be received by means of a crane pulley or fixed over the door on the north gable of the building; to which door a ladder, or flight of stairs on the outside may communicate. The garret may occasionally be made use of as a store room for corn, that has already been preserved two or three years in the chamber below, or for other kinds of dry goods , leaving a few air holes only in the gable ends of this garret story.

The top floor with three chambers is where the corn is first stored for between a year or two till perfectly cured or sold. Each chamber about 13 feet square by 12 high; to be divided from each other by brick partitions carried up from the ground. The sides of these chambers to be neatly covered with stucco plaister.

The floors of the chambers, to be supported with whole double deals laid edgeways, and covered with narrow deal boards, not exeeding six inches in breadth, leaving a space of near an inch between each board, that room may be given for the air to ascend equally, in order to ventilate the corn. These floors, or at least the interstices between the boards, to be covered with close wire grating, that will not admit the grain to pass through, or the floors may be covered with a proper thin, but strong hair cloth, nailed down round the confines of the floor, before the corn is lodged.”

The small trap doors above each of the three main double doors; “To be made a foot square each one in the centre of each floor, which may be opened occasionally, to let out the corn into the ground chambers for use or sale; and may at such times, if a brisk wind sets in and through the ground chambers, prove a good winnowing to such corn to prepare it for market, especially if the said trap doors be humoured by the hand, so as to let the stream of corn thin and diffused on the clean ground floors. These trap doors to be free from wire grating or hair cloth; to be affixed by hinges, so as to open into the ground chambers; at other times kept fastened with a cross iron bar staple and pad-lock, to prevent imbezelment. The ceiling of the chambers must be made as much air proof as may be, either by some excellent close plaister ceilings, or only by caulking the joints in the garret floor above, pitching the seams afterwards, and dashing drift sand on the seams after the hot pitch brush, by which means no air can pass out of the chambers except through the flues.

The flues to be made of a piramidal figure, with beams erected at the four angles of each flue, well barred and braced together, and covered with laths and plaister, so as to be tight and air-proof; to be four feet sqaure at their bases, and well fixed in the garret floor, and to the roof timbers; to be erected directly over the trap doors and elevated twelve or fourteen feet above the ridge of the roof of the building; their openings at their tops to be a foot sqare each; a piece of brass net-grating to be fixed half an inch within their muzzles, to prevent sparrows or other annoyances descending to the corn below, and also to admit of a cover or valve, falling close on thier muzzles.

These muzzels to be well guarded from rain and snow by proper umbrelloes elevated a little above them, and well fixed to the continuation of the four beams of the flues. The valve just mentioned to be made of square pieces of oak board exceeding the square dimensions of the orifices of the flues, by two inches on every side, a plate of lead of five or six pound weight, to be nailed on the top of each valve; the valves underneath to be lined with buff, well soaked in pickle, to attract the moisture of the air, swell and stop close. These valves to open or shut by means of a small cord, fastened to a very short cross sling of the like cord, which cross sling communicates, and is made fast to four staples in the four corners of each valve; the valves may be raised and lowered evenly on their respective muzzels, by means of the small cord passing over a pulley fixed under the centre of the umbrello, and down between the lath and plaister, and the boarded lining of the flue cones out to hand in the garret, through a small hole in one side of the flue... The chief use of these valves (and a very considerable one) is the keeping out the moist air from descending upon the corn, when the granary is not to be ventilated.

Trap doors in the garret floor, for laying in the corn into the top chambers; to be two foot and a half square each, well fitted to thier receiving jambs, and made tight with clay well tempered with salt and water, after the chambers are charged with corn.

The ground, or lowest chambers that should be admitted in a building of this nature, the sides of which to be smooth plaistered, that rats or mice may not be able to ascend to the corn floor, nor should any goods or lumber be admitted into these ground chambers because they would diminish the diameter of the quantity of air to be admitted into them, and consequently of its weight and pressure necessary to force its way up through the interstices left in the corn floor, as before described.

Large folding doors to each ground chamber, openeing outwards, which when set open and properly fixed may catch the drying sidewinds, and direct them into thier respective chambers. The like folding doors to be on each side of the building, East and West opposite to each other, so that upon ventilating the corn above, the windward doors only are are to be opened; at all other times, when moist weather prevails, all the doors, as well as the valves before mentioned, to be kept shut and close as possible...Mice and gross vermin, will find great if not insuperable difficulty, to get admittance into this granary, and insects investing it, may be destroyed by brimstone set on fire occasionaly in the ground chambers, keeping the folding doors, as well as the valves above, close shut at such times as stoving, and it should be well stoved before it be replenished with corn.

It is sufficient only to remind many peaple, that the acid fume of brimstone confined, kills all insects within its circulation, and no doubt discourages their approach for some time after; and may probably tend to abate fermentation in the grain, which is generally, if not always, occasioned by superabundant moisture and heat. When the folding doors are open, the air current is directed into the ground chambers, flowing through the board gaps of the floor above and through the corn quite forcefully when the flues are open.

The ground chambers need not be above seven feet high, under the floor timbers; and a brick floor or one of clay, lime, and smiths dust well tempered together, is fittest for the ground floor...The distinction and difference between sound and tainted or damaged wheat, and their different treatments in or to their preservation in this kind of granary - If wheat be dry and well saved at harvest, free from black, blighted, or sooty ears, has afterwards had its due sweat and melioration in rick cock, or barn for five or six months, and after threshing out has been well cleaned and sreened; such wheat may truly be called sound, and well lodged in this kind of granary, may be easily preserved therin for many years, by ordinary and moderate ventilations. For instance, being thrashed out in January or February after reaping, well cleansed, and lodged in the granary; it may be ventilated once a week, if oppurtunity offers, for the first two or three months in spring, which will be a great advantage to the grain, befor the sultry heats of summer come on, when it should be ventilated as often as a proper breeze or gale of wind offers, and once a month, a few matches of brimstone set on fire in the ground chambers, as before directed; In the Autumn, Winter, and Spring following, two or three times a month may be sufficient to ventilate, without applying the brimstone fumes , but the second summer, ventilate twice or thrice a month, and apply the fumes once or twice during this second summer after which time it may be sufficient to ventilate once a month during the second Autumn, Winter, and Spring, and twice a month during the third Summer, when it may be said to be thoroughly cured.

Good corn that has been well preserved in common granaries, by frequent turning and winnowings, and afterwards laid two or three foot deep, or more, seldom sweats, or ferments after the first two years...except it receives accidental moisture, from which it is easily freed with a little care; wheras it is a long time parting with its natural internal moisture, which is the greatest enemy to its preservation.
It is no less certain that wheat, being well preserved by any method whatsoever, has after several years so kept, been found to produce more and better flour for bread than some of the same field and crop did soon after its being threshed out; because the aqueous humidity of the grain evaporating by keeping some years, the flour comes cleaner from its thin Bran under the stone.
It is equally certain, that wheat so preserved for several years, has proved very good seed corn, and probably not so liable to produce the smutty ear; Excess of moisture, either in the seed, the soil, or the seasons, being the cheif cause of that grievious complaint, except the seed itself be Smutty, and the crop also will be Smutty notwithstanding dry seasons.

But if wheat has been ill saved at harvest, or be in a contrary condition, in any or all respect, to be sound wheat described above, which would certainly give it a strong tendency to heat and fermentation, in a bulk of ten or twelve feet deep, and so induce the weevil and other maladies, to the further damage or destruction of the wheat. It would therfore, in this case, be necessary first to cleanse well by screen or tryer, after which give it a very gentle and slow drying upon a kiln, equal only to a strong sun heat, till the grain be somewhat hard under the teeth; then laying it on a floor to cool, for some hours, put it into sacks half filled and tied fast, and so rub the wheat well therin on a smooth floor with both hands, frequently turning the sacks over every way, in order to loosen and free the grain from its black sooty dust; then winnow clean, after which it may be laid into the granary ten or twelve feet deep, and there treated in every respect like wheat originally found. Such wheat after such a treatment, will turn out much better bread, though kept two or three years or more in this granary, and sell for a good deal more money than it would have fetched in its fist tainted and foul conditions. Yet such wheat, though by this method made proper for bread, should by no means be used for seed; for kiln drying , more or less, abates or destroys its vegetative quality; and even without drying, a distempered seed seldom or never fails of producing a distempered crop”.