Bourne Archive: Muspratt: Malting

Annotated web page 2011 R.J.Penhey                      http://boar.org.uk/aaiwxw3MusprattB2Malting.htm       Latest edit 23 Jan 2011


 

The Bourne Archive

 


Muspratt’s Chemistry, Theoretical, Practical & Analytical (ca. 1859)


Extracts Concerning Beer, 2: Malt and Malting.


The web pages intended to be linked from this introduction are from an article on brewing, under the heading ‘Beer’. The original article is presented here in several web pages, respectively dealing with: 1, barley; 2, malting; 3, water; 4, hops; 5, grinding malt; 6, mashing; 7, saccharometry; 8, boiling; 9, cooling; 10, fermentation; 11, cleansing.


Vol. 1. pp. 236-244.

MALT AND MALTING.—In various parts of Peru, large quantities of maize are converted into chica; and it is a remarkable fact, that the grain used in all such cases has been made to undergo the process of malting, a proof that the making of malt must have been known to the inhabitants of that country from a very remote period.

Oats, peas, beans, maize, buckwheat, and common wheat, are all capable of being malted, and have been experimented upon, but barley is most prized for this purpose.

 The heaviest grain is recommended, as, if in good condition, it gives malt of corresponding gravity

What is here intended to be understood by the heaviest malt is, that it shall be of a tender and friable nature throughout, and without hard ends, which are generally more similar in composition and properties to barley than to malt. The perfect article is not always attainable, even with the best skill or management, and it would, on this account, be improper to pass lightly or carelessly over such an important subject.

Malt may be very heavy and yet hard, too much so the bear the name of malt; and the inexperienced may be greatly deceived, unless they have sufficient knowledge to discriminate between the several varieties sent into the market. At the present time the difference is from one to eight shillings per quarter; within the last thirty years, however, it has been as high as from one to sixteen shillings per quarter.

If malt is short of the extract, in comparison with that of the best quality, it is also deficient of fine flavor.

The utmost skill is required to produce a malt of abundant sweetness and friability; when these are attained, it will never be too heavy.

If the brewer is also a maltster, as he ought to be, both in knowledge and in practice, he can procure malt any color he pleases; but even if he be not, there will be no great difficulty in giving the necessary order for any peculiar tint or flavour, either pale, amber, brown, or any intermediate shade.

Much space might be occupied in giving a full dissertation on this subject; it will therefore be treated of in as concise and clear manner as possible, so as to include the principles and main features of the most approved systems.

The whole process is comprised under these successive operations: steeping, couching, flooring, and kiln drying.

Steeping.—Without the first—steeping—the grain will not vegetate, which is requisite before its nature can be changed.

The steeping is usually performed in large wooden or stone cisterns, into which the grain to be malted, already screened down and nicely levelled, is shot; it must be charged with liquor to six or seven inches above the barley, and although the grain has been well cleaned, there will always be some light grains and other matter floating on the surface of the liquor, which must be skimmed off, otherwise, if retained, they would impair the quality of the article, and also the flavour of the beer made from it. However, the improved cultivation of the soil, and the new varieties of barley, have of late years done away with the necessity of skimming.

In consequence of the absorption of moisture, the grain swells to about one-fifth in bulk, and increases about fifty per cent. in weight, one hundred pounds of barley thus becomes one hundred and fifty.

The object of steeping is to expand the farina 1 of the barley without humidity, and thus make the seed fit for germination, when subsequently exposed to the air. Too much steeping is injurious, because it prevents the germination at the proper time, in consequence of the air being excluded whilst the superabundance of water is spontaneously evaporating; it is hurtful, also, in extracting a portion of the saccharine 2 matter. The maceration is known to be complete when the grain may be easily perforated with a common needle, and is swollen to its full size; or if a barley-corn, when taken between the thumb and fingers and pressed, sheds its flour upon them, it is ready; but not if it continues entire, or its substance exudes as a milky juice, it is either, in the first instance, not sufficiently steeped, or, in the latter, the steep has been too long continued, and the grain is spoiled for germination.

In warm weather it sometimes happens, that, before the grain has completely swelled, the water becomes acescent 3; this circumstance, which is very soon discovered, may be immediately remedied by drawing off the foul liquor by means of the tap at the bottom of the cistern, and replacing it with fresh cold water. No harm is done even if it be renewed three times during one steep.

The time of steeping, which varies according to the temperature and other circumstances, requiring in winter a longer and in summer a shorter period, is reckoned technically by the term tide, each being of twelve hours’ duration. In winter it may extend over five and a half or six tides, from the time the liquor is put into the cistern to the time of letting, sixty-six or seventy-two hours; at others it will cease to swell much sooner, but, as a general rule, it should lie in the cistern until it will no longer swell, after which, the liquor being drawn off, it should be left to drain for six hours before it is emptied into the couch. If now the skin, which is somewhat loosened, will be partially removed from the kernel, and the two ends are slightly pressed, the latter will be seen to be partly separated.

The couch.—The water being drawn off, and a fresh quantity occasionally passed through, to depurate 4 the grain from any slimy matter which may have been generated, it is laid upon the stone flag-floor of the couch in square heaps, from twelve to sixteen inches in depth, and left in that position for twenty-four hours.

The bulk of the grain being greatest at this time, the revenue officers may, if they think fit, gage it. The surface of the barley is now so entirely freed from moisture, that it does not feel damp. By degrees, however, it becomes warm, its temperature being 10ฐ above that of the atmosphere, and it gives out and agreeable fruity smell. If at this time the hand is thrust into the heap, it gets bedewed with moisture, and at this sweating stage the germination commences; the fibrils of the radicle5 first shoot forth from the tip of every grain, and a white elevation appears, which soon separates into three or more rapidly increasing radicles. About a day after this the appearance, the plumula 6—acrospire of the maltster—peeps forth from the same point, and would proceed under the husk until it appeared at the other end of the seed, as a green leaflet; but this never happens in malting, as the operation is finished before it takes place.

About ninety-six hours after the barley has been taken out of the steep, the heat is the greatest, consequently the radicles increase in length with great rapidity, and must be checked by artificial means, which constitute the chief art of the maltster.

The barley must be spread out thinner upon the floor, and turned several times a-day—as shown in Fig. 150—the interior being always brought, by the spades of the workmen, to the surface. The depth, originally fifteen or sixteen inches, is lessened slightly at each turning, till it is at last not more than three or four inches. Two spadings per day are generally requisite. At this period of spreading or flooring, the temperature in England is about 62ฐ Fahr., but in Scotland only 56ฐ or 57ฐ.

The rudiments of the stem, or the plumula, sprout forth about a day after the appearance of the radicles.

To a limited extent the barley absorbs oxygen and emits carbonic acid 7, just as animals do in breathing; the grain loses from one and a half to three per cent. of its weight upon the malt floor, a portion of this being due to waste particles. As the acrospire creeps along the surface of the seed, the constituents undergo a remarkable alteration. The gluten and mucilage in a great degree disappear, the color becomes whiter, and the substance so friable that it crumbles into meal between the fingers. This is the great object of malting, which is accomplished when the acrospire has reached the end of the seed. At this period the growth must be completely stopped. The duration of the germination in England may be reckoned fourteen days; but in Scotland eighteen or even twenty-one are required, owing to the lower temperature of the couch.

The shorter the period within these limits the better, as there will be a quicker return of capital, and the malt produced is superior. In dry weather it is sometimes necessary to moisten the barley upon the couch.

If an offensive odor, somewhat resembling that of rotten apples, be observed to arise from the couch, it is a bad omen, showing that either the quality of the barley was inferior, or that, through carelessness, the workmen have crushed a number of grains in turning.

 On this account, when the weather causes germination too quickly, it is better to arrest it by spreading the heap out thinner than by turning it too often.

Comparing different samples of barley, it will be found that the best develop the acrospires quicker than the radicles, and thus give rise to a greater production of the saccharine principle; this conversion advances and keeps pace with the acrospires, so that the portion of the grain to which it has not reached remains in its unaltered starchy state. It is never complete till the acrospire has attained the opposite end to that from which it sprung; hence one portion of the corn may be sugary, while the other is still tasteless. If the grain was allowed to vegetate beyond this term, the radicles being one-third of an inch long, the future stem would become visibly green, it would shoot forth rapidly, the interior of the grain would appear milky, a complete exhaustion of all its useful constituents would ensue, and nothing but husk remain.

In France, the brewers, who are generally their own maltsters, seldom leave the barley on the couch longer than eight or ten days, which is too short a period, even when allowance is made for the extra warmth of the climate; hence the wort, made from the same quantity of malt, is much inferior to that of the English brewer.

At the conclusion of the germination, the radicles have become once and a half as long as the barley, and are so contorted that the corns hook one into another, but the acrospire is just beginning to make its appearance.

A moderate temperature is best fitted for malting; it cannot, therefore, be well carried on in the heat of summer or the cold of winter. Malt floors should be placed in substantial thick-walled buildings, the more concealed from the rays of the sun the better, so that a temperature of 59ฐ or 60ฐ Fahr. may uniformly pervade the interior. They are said by some to be better when sunk slightly under the surface of the ground, provided that the situation is dry.

During germination, portions of the glutinous constituent of the grain disappear, which is conjectured have passed into the radicles, while a portion of the starch is converted into sugar and mucilage. The change is similar to that which starch undergoes when dissolved in water, and digested at the heat of about 160ฐ Fahr. with a little gluten. The thick paste becomes by degrees liquid, transparent, and sweetish to the taste, the solution containing sugar and gum mixed with some unaltered starch. At the same time the gluten undergoes a change and becomes acescent3, so that only a certain amount of starch can be thus modified by a quantity of gluten. By the artificial growth upon the malt floor, the whole of the gluten and albumen is not decomposed, and only about one-half of the starch is changed into sugar; by a continuance of the germination, the remainder would only assist the growth of the roots and stems, but it is nearly altogether converted into sugar without any very great waste of substance, in the brewer’s operation of mashing.

If the grain is suffered to sprout in the couch, it will never be even afterwards, as those corns which are sprouted will attract more than their proper share of moisture; moving and turning in due time will, however, retard this, and cause each corn to shoot almost simultaneously.

The FlooringIn this operation the grain is turned inside out from the couch into the bed, which is made to occupy two or three times as much space as the former, according to the temperature. It may lie here for about six hours, observing in the interim whether the grains are commencing to shoot; or, if this is not the case, giving it a gentle turning, and spreading it out thinner, before the expiration of the period named; it may be laid all the width of the floor, and permitted to remain for another six hours, when all the healthy corns will be sprouted; it is then again thinned, and after this, while it is in full vigor, often turned; by this means the root is kept short and bushy, and retains the moisture as long as is requisite, to the period of its withering, if the process be of sufficient duration, without sprinkling.

The root begins to fade about the eleventh or twelfth day.

If, on taking a handful of the grain from the floor, it smells faint, and the skin is glossy or wet, it requires turning. After this it will smell fresh, and the grain, instead of being glossy, will be dry. If the turning is omitted at the proper time, the root will be of unequal length.

On the grain beginning to wither, it may be spread out thicker, to generate a little more warmth, and to mellow it, still keeping it frequently turned, to prevent a glossy appearance, until the moisture is further expelled, and also to retard the progress of the acrospire.

The grain, when ready for drying, must easily rub to meal between the fingers, after being deprived of the skin.8

Kiln-dryingWhen the malt has become perceptibly dry to the hand upon the floor, it is taken to the kiln and hardened with artificial heat, to prevent all further growth, and enable it to be kept, without fear of change, for use.

The malt should be evenly spread upon the drying cloth, or floor, in a layer varying from three to ten inches in thickness, according to the variety which is to be produced, and heat from 90ฐ to 100ฐ Fahr. steadily maintained, till the moisture is for the most part driven off. During this time the malt must be turned over, at first frequently, and, towards the conclusion, every third or fourth hour. When nearly dry, the temperature of the kiln should stand between 145ฐ and 165ฐ Fahr., and this heat must be maintained till the grain has acquired the desired color.

The fire is now allowed to die out, and the malt is left on the kiln till sufficiently cool, this result being greatly accelerated by the stream of cold air rising up through the bars of the grate. Thoroughly dry brown malt may, however, by damping the fire, be taken hot off the plates, and cooled in some contiguous apartment. The kiln-drying should not be hurried; many persons occupy two days in the operation. The malt, when prepared, must be kept in a dry loft, where it can be occasionally turned over till used.

The temperature of the kiln should, in all cases, be most steadily maintained, and, when required, gradually elevated.

If the drying commences with too great a heat, the outer part of the grain hardens, and prevents the interior moisture from evaporating; should this be driven off by too high a temperature, the husk will, in all probability, split, and the farina become horny and very refractory 9 in the mash.

It is preferable, therefore, to brown malt by long-continued moderate heat, than to apply a strong one for a shorter period, which might carbonize a portion of the mucilaginous sugar, thereby deteriorating the value of the product.

In this manner the sweet, very often changes to a bitter principle.

During the drying, the roots and acrospire of the barley become brittle, and are, by the friction of turning, et cetera, broken off, and are afterwards separated by a fine wire sieve—Fig. 151. This operation is termed cleaning.

The bulk of good malt exceeds that of the barley from which was fabricated, by about eight or nine per cent.

The benefit derived from kiln-drying is not merely confined to the expulsion of the moisture, a portion of the starch which was unchanged is by it converted into sugar in a double or twofold way: firstly, by the action of the gluten upon the fecula at an elevated temperature; and, secondly, by the incipient roasting the starch is subjected to, giving it a kind of gummy nature.

This is illustrated by the fact that malt, freed from moisture as much as possible in a dry atmosphere without heat, yields much less saccharine extract than that dried ordinarily. Moreover, kiln-dried malt has a peculiar, agreeable, and faintly-burnt taste, probably from some empyreumatic oil 10 generated in the husk, and which imparts its flavour to the beer, at the same time that it assists in preserving it. The skilful preparation of the malt must necessarily exercise a very great influence on the worts which are prepared from it. If the germination be pushed too far, a portion of the valuable matter is wasted, while, if it is not carried on sufficiently long, the malt will be too raw, and much of its starch will remain insoluble; if it is too highly kiln-dried, a portion of the sugar will become caramelized and bitter; and if the sweating was irregular or imperfect, much of the barley may be lumpy or useless.

The grains of good malt are round and full, break freely between the teeth, have a sweetish taste, an agreeable smell, and are full of soft flour. They give no unpleasant taste on being masticated; are not hard, so that they will give a free white streak, like chalk, when drawn contrariwise to the fibres of wood; and, lastly, will swim on water, as is not the case with unmalted barley.

Malt-kiln.—The construction of a well-contrived malt-kiln is shown in Figs. 152, 153, 154, 155: the first being the ground plan; the second, a vertical section; the third, a horizontal, and fourth, a vertical in the line of the malt plates. The same letters in each of the figures are indicative of similar parts.

In the middle, upon a wall of brickwork four feet high, is supported a cast-iron cupola-shaped oven, and beneath it are the grate and ash-pit. The smoke escapes through two equidistant pipes into the chimney. a is the grate, nine inches below the sole of the oven, b; c c c c, are four strong nine-inch pillars of brickwork bearing the stone lintel, m; d d d d d d, are similar supports for the girder and joists, upon which are laid perforated plates; e indicates a vaulted arch on each of the four sides of the kiln; f is a space between the kiln and the side arch, allowing of the inspection and cleaning of the kiln; g g, walls, on which the arches rest, on each side of the kiln; h, the ash-pit; k is the furnace-door; and l l are junction pieces connecting the pipes, r r, with the kiln.

These smoke-draughts rest about three feet from the walls, and a similar distance from the malt-plates, upon iron supports secured to the arches. They are indicated in the vertical section—Fig. 153—by the letters u u; at s s—Fig. 155—they enter the chimney, to which is supplied two register or damper plates intended to regulate the draught. These registers are represented by t t; the lintel, m—Fig. 153—is intended to cause the heat to spread laterally, instead of ascending in one mass in the middle, and prevents any combustible particles from falling upon the iron cupola; n n are the main girders of iron supporting the joists, o o, of the same material, upon which the perforated plates, p, lie; q is a vapour pipe in the middle of the roof, allowing the steam of the drying malt to escape.

This kiln may be heated either with coal or wood. The size is about twenty feet square, but it may be either proportionally enlarged or diminished, as seems advisable. The perforated floor should be large enough for the contents of one couch or steep to be spread out upon.

It can be heated by means of steam pipes, laid irregularly, or in parallel lines under it, or a wire-gauze web might be extended upon such pipes. This steam apparatus might, without danger, be supported by joists of timber. For drying the pale malt of the brewers, this plan is well adapted.

Gas-DryingA patent was recently granted to Mr. HALLEWELL of Leeds, for improvements in malting, on consequence of drying by gas instead of the usual process. This invention is stated to augment the yield of malt twelve per cent., that is, something like one bushel out of every eight malted.

The malt to be dried is laid on an ordinary perforated floor of iron plates, and very small jets of gas are applied within 5ผ inches of its under side.

During the first twelve hours the temperature rises to 70ฐ Fahr.; at the expiration of forty hours, it reaches 120ฐ without any increase in the consumption of gas.

When this degree has been attained, the malt is, comparatively, perfectly dry, and quite pale. It is very fine in appearance, and remarkable for its peculiar sweetness; and being freer from moisture than most malt kilned in the usual way, as on analysis it only gave 5ท89 per cent.—see page 243 11—it passes through the rollers grinding in one-fourth less time than the ordinary product. The cost of exsiccation 12 is said to be about two per cent. over that by the common method; but as the produce is above twelve per cent. more, there is a clear advantage.

According to Mr. HALLEWELL, the worts are drawn so closely from his malt as to be below four pounds per barrel gravity. He says:—If the worts were drawn as low from cinder-dried malt, the acid of the liquor would be so strong as to be quite nauseous and injurious.

The advantages and beneficial effects of this new system of desiccation, no doubt, arise in part from the small quantity of water which the malt contains, and absence of sulphur, of which there is always a certain amount in the coke ordinarily used for drying; the result is the evolution of sulphurous acid, which certainly affects the malt, bleaching it, and leaving some sulphuric acid behind, which when water free from carbonate is employed, seriously interferes with the fermentation.13

Regarding the truth of the foregoing statement of the increase consequent upon the use of gas-dried malt, the Editor has had no immediate opportunity of judging; but it has been corroborated by very eminent brewers in London and elsewhere. This invention must be of material importance in other cases than that of making beer; but especially brewers will benefit by it, more so when the duty on malt is high.

MALTING IN MUNICH.—The barley is steeped till the acrospire seems to be quickened 14; a circumstance indicated by a swelling at the end of the grain which was attached to the footstalk, as also when, on pressing a pile between two fingers against the thumb nail, a slight projection of the embryo is perceptible. As long, however, as the seed-germ sticks too firm to the husk, it has not been steeped enough for exposure on the underground malt floor. Nor can deficient steeping be safely made up for afterwards, by sprinkling the malt-couch with a watering-can, which is apt to render the malting irregular. The steep-water should be changed repeatedly, according to the degree of foulness and hardness of the barley: first, six hours after immersion, having previously stirred the whole mass several times; afterwards, in winter, every twenty-four, but in summer, every twelve hours. It loses none of its substance in this way, whatever vulgar prejudice may think to the contrary. After letting off the last water from the stone cistern, the Bavarians leave the barley to drain in it during four to six hours. It is now taken out, and laid on the couch floor in a square heap, eight or ten inches high, and it is dexterously turned over, morning and evening, so as to throw the middle portion upon the top and bottom of the new-made couch. When the acrospire has become as long as the grain itself, the malt is carried to the withering or drying floor, in the open air, where it is exposed in dry weather, during eight to fourteen days, being daily turned over three times with a winnowing shovel. It is next dried on a well-constructed cylinder, or flue-heated malt kiln, at a gentle, clear heat, without being browned in the slightest degree, while it turns friable into a fine white meal. Smoked malt is entirely rejected by the best Bavarian brewers. Their malt is dried on a series of wove-wire horizontal shelves, placed over each other; up through the interstices or perforations of which, streams of air, heated to only 122ฐ Fahr., rise from the surfaces of rows of hot sheet-iron pipe flues, arranged a little way below the shelves. Into these pipes the smoke and burned air of a little furnace on the ground are admitted. The whole is enclosed in a vaulted chamber, from the top of which a large wooden pipe issues, for conveying away the steam from the drying malt. Each charge may be completely exsiccated on this kiln in the space of from eighteen to twenty-four hours, by a gentle uniform heat, which does not injure the diastase, or discolour the farina.—Ure 15.

In concluding the account of Malting, the Editor cannot refrain from making a comparison between the present system and the ingenious and excellent one lately patented by Mr. W. L. TIZARD 16, the eminent mechanical and consulting engineer of London.

It is well known that even an ordinary malting establishment includes an extensive range of buildings, containing a cistern, a couch, extensive floors, and the kiln. Mr. Tizard’s newly-invented malting apparatus consists of a vertical cylinder, containing a series of wire trays, provided with sprinkling and turning apparatus and steam pipes, vacuum and plunge pumps, vacuum and pressure gages, thermometer, et cetera, and worked throughout the whole year with 75 per cent. less labor, and 50 per cent. less fuel than the old one. Experienced men admit, that of late the harvests have been so unpropitious, that the farmer is unable to secure his barley crop sufficiently dry for the purpose of the maltster, and the latter asserts that it is necessary to dry or sweat the grain artificially in a kiln, previous to its saturation with water in the cistern. The process of sweating is, however, neglected, on account of the great trouble it gives, or from there not being an extra kiln provided for the purpose. Hence the malting is commenced in a slovenly and imperfect manner. The temperature of the steeping liquor, and the number of hours allowed for the saturation of the grain, are also disregarded as matters of routine, notwithstanding that they are points of very great importance as affecting its manufacture into malt. With the new apparatus, the process is commenced and finished in one vessel, which is a cylinder, occupying but one-twentieth the area of a malt-house. The barley gravitates from the stores above into each tray; after which the door is screwed up, and the cylinder made air-tight. The conversion of the grain into malt commences thus:—A current of steam is passed through a series of tubes lying under the bottom of each tray, which imparts its caloric to the grain, by which all superfluous moisture and atmospheric air escape from each corn in the form of vapour. When the contents of the cylinder are heated to the temperature of about 100ฐ Fahr., the vacuum pumps are put into motion, by which such vapour is extracted, and a partial vacuum created. The atmospheric pressure being thus removed, and the dilatation of the grain effected, a vacuity necessarily exists in the pores and interstices of each corn. In this favourable condition it imbibes steeping liquor at a temperature of 53ฐ. Thus the steeping is accelerated, and a perfect saturation produced. The grain is now allowed to germinate; but throughout this interesting process, the laws of nature are subject to the controlling hand of science, which has here brought to its aid all the mechanical means necessary to achieve the great object of the maltster, namely, that of thoroughly exposing and making available the whole farina of the corn, without which the article would be imperfect. This is effected and kept within the range of proper temperatures by a steady sprinkling and evaporation of cold water, accompanied by the constantly evolving carbonic acid, which are together removed by the vacuum pumps. On the other hand, its temperature might be increased, and the process accelerated, by occasionally applying the plunge pumps, which subjects the manufacture to atmospheric pressure. The great revenue arising from the malt duty will, to a moral certainty, render this invention as acceptable to Her Majesty’s Commissioners of Excise, and the Chancellor of the Exchequer, as to the honest maltster; inasmuch as it admits of being locked up, like a rectifier’s still, as soon as the barley is introduced, and need not be opened till the manufacture is complete, and the malt ready to be removed to the stores; so that the whole process is proof against fraud, and the daily supervision of the officers of Excise could be dispensed with.

Space will not admit of a disquisition on the comparative merits of the old and new processes of couching, flooring, sprinkling, germinating, turning, heaping, and withering, but a brief description of the curing or finishing process, termed drying, cannot be dispensed with. This can be accomplished without the painful experience of having destroyed the vitality of the grain by the barbarous shovel, or the soles of the feet; by excessive light, cold or hot currents, or other incidental causes. Presuming, then, that the new apparatus has supplied the necessary moisture and atmospheric air, and abstracted all superfluous caloric, and the carbonic acid gas 17 generated by the germination of the grain, which it cannot fail to do to perfection, the drying is performed as follows:—Steam is passed through the pipes, speedily raising the temperature of the contents of the cylinder to 90ฐ or 100ฐ. The vacuum pumps are also put in requisition, which immediately extract the steam as it flows out of the grain, preserving a partial vacuum on its exterior, during the withdrawal of the whole of the moisture. The malt is thus thoroughly dried in a distended form, and its original plumpness is preserved. It is acknowledged that the palest malt produces the largest amount of extract, and that it cannot be too pale if properly desiccated. The apparatus thus briefly alluded to , has been designed by a practical maltster and brewer, with a view to advancing one of the most important of our national manufactures, and one which is most susceptible of improvement, the common malting processes being rude and unsatisfactory in the extreme. Here is a complete set of apparatus to enable an intelligent operator to control the various processes of sweating, steeping, and converting the farina of his corn into sugar, and of exsiccating it to perfection, without imparting the least possible color or contraction of the grain. Indeed, malting is now reduced to a science, and cannot fail to meet with the support of the Government, and the most intelligent of the malting and brewing communities. For the pale ale brewer, this invention ought certainly to be invaluable, and the Editor would strongly recommend the leading firms at Burton and elsewhere to introduce the apparatus into their establishments. 18

Before proceeding further, it will be advisable to dwell very concisely on the composition of raw and malted barley.

The analysis of barley-meal has been made by EINHOFF; but the results which he obtained are so extremely discordant with those obtained by others, that they do not at present seem to be worthy of confidence.

PROUST 19 affirms that barley contains a peculiar proximate principle, which from the Latin name of the grain, has been denominated hordein. He describes it as a yellow, granular, woody powder, in appearance very much resembling sawdust; and says that it disappears in great quantity during malting, being resolved chiefly into starch and sugar. Does it not disappear wholly?

Annexed is the mean of ten analyses of barley performed by HERMBSTADT:—

 

Centesimally

represented

Water, ………………………………………………..

10.48

Husk, ………………………………………………….

11.56

Gluten, ………………………………………………..

4.92

Albumen, …………………………………………….

0.35

Starch, ………………………………………………..

60.50

Sugar, …………………………………………………

4.66

Gum, …………………………………………………..

4.51

Oil, ……………………………………………………..

0.35

Soluble phosphates, et cetera, …………………

0.36

Loss, …………………………………………………..

_2.31_

 

100.00

PROUST states that barley-meal contains:—

Hordein, ……………………………………………..

55.0

Starch, ………………………………………………..

32.0

Sugar, …………………………………………………

_5.0_

 

92.0

Dr. T. THOMSON gives no hordein, but:—

Starch, ………………………………………………..

88.0

Sugar, …………………………………………………

_4.0_

 

92.0

The analyses of PROUST and THOMSON agree exactly, only one takes the 88.0 to be solely starch; while the other assumes it to be a peculiar principle and that body. 20

The same statement is applicable to the principal constituents of malt, as given by these chemists, thus:—

 

Proust

Thomson

Starch, .

56.0

69.0

Hordein,

12.0

_—_

 

68.0

69.0

The sugar found in the barley was, no doubt, the result of the action of some of the reagents employed by the above chemists on the starch.

EINHOFF’S analysis gives sugar in the same proportion as PROUST and THOMSON, but represents the quantity of starch as more than double that found by the former.

Dr. THOMSON is of opinion that the hordein, instead of being a proximate principle 21, is merely starch in a peculiar state, somewhat similar to the fibrous matter of potatoes, malting having the effect of converting it into starch and sugar by destroying a certain unknown glutinous substance, which holds the particles firmly together.

The presence of a singular substance in barley-meal in so great a quantity as more than fifty per cent., its being woody and insoluble in water, both cold and boiling, its disappearing during the malting, and the increase in gum, sugar, and starch in consequence, are properties not attributable to any component part of the grains with which chemists have hitherto been acquainted. Hence, hordein has been, and is now, admitted by many to be a peculiar substance. According to GREGORY, its composition is C12H8O8, or C12H10O10.

If this analysis is correct, it is almost impossible to view hordein as a principle; it seems rather to be an allotropic modification of starch. It is very probable that this state is owing to some impurity or extraneous matter, and that, could this be removed, it would be found to consist of starch only. There is no doubt that, at some future period, the number of the principles now regarded as peculiar will be reduced, and many of them proved to be identical with each other, only existing under different circumstances.

The amount of inorganic matter in different specimens of barley, varies very considerably. This might be anticipated from the fact, now generally admitted, that the nitrogenized or nutritive principles of grain or seeds, bear a relation to the phosphoric acid present; thus, if the quantity of the latter be small, it follows that the amount of nitrogen is proportionally deficient, and the nutritive effect of the grain will be comparatively low in the scale, because the solubility of the albuminous matters, and, therefore, their capability of being carried into plants, appears to depend on the presence of the phosphates.

Dr. R. D. THOMSON says—In the analyses which have been published of this nature, the manipulators have omitted to state whether the husks were included in the grain burned by them. In the following results the omission has been filled up:—

 

Barley Flour

_____Barley with Husks______

 

R. D. Thomson.

R. D. Thomson.

Horsford.

Way

Inorganic matter per cent.,

4.02

3.20

2.70

2.34

2.48

Horsford’s is the mean of ten, and WAY’S of four experiments.

The following was found to be the composition of the ash of barley and malt:—

 

Centesimally represented 22

 

R. D. Thomson

 

Barley.

Malt.

Potassa 23, …….

16.00

14.54

Soda, …………….

8.86

6.08

Lime, …………….

3.23

3.89

Magnesia, ……..

4.30

9.82

Oxide of iron, ..

0.83

1.59

Phosphoric acid,

36.80

35.34

Sulphuric acid,

0.16

—

Chlorine, ……….

0.15

trace.

Silica, ……………

29.67_

28.74_

 

100.00

100.00

The composition of a sample of barley, and of malt made from it, thus showing the alteration in the grain by malting, is here given:—

 

________Barley.________

 

_________Malt.________

 

Natural state.

 

At 212ฐ.

 

Natural state.

 

At 212ฐ.

Carbon, …

41.64

..

46.11

..

42.44

..

43.93

Hydrogen,

6.02

..

6.65

..

6.64

..

7.00

Nitrogen,

1.81

..

2.01

..

1.11

..

1.29

Oxygen, …

37.66

..

41.06

..

43.08

..

46.51

Ash, ………

3.41

..

4.17

..

1.68

..

1.27

Water, …..

_9.46_

..

__—__

..

_5.05_

..

__—__

 

100.00

 

100.00

 

100.00

 

100.00

The mean of a number of experiments relative to the loss which barley sustains by malting, indicated nineteen per cent.

The whole of the loss is not solid matter, as barley uncrushed contains 13.1 per cent. of water; and malt, in the same condition, 7.06 per cent. Mr. E. E. HOLDEN, student in the Editor’s college, found in ordinary cinder-dried malt, 7.68 per cent.

There thus remains thirteen per cent. of solid loss.

A mean of several trials gave for the ash of barley 3.0; and for that of malt, 2.52 per cent. Now, as one hundred of the former are equal to eighty of the latter, the quantity of ash which malt should contain is 2.42, if the loss of organic and inorganic matter was equable, which it is observed to be, almost approximately, from this experiment; for the relation of the ash which has disappeared, or 0.48 per cent., bears almost the same proportion to the organic matter removed, as the total quantity of ash in barley does to the whole of the organic matter in the grain. Thus, barley contains eighty-four per cent. of dry organic matter and three per cent. of ash, while malt has lost 0.48 per cent. of ash, and 12.52 of organic matter, by calculation—

As 3 : 0.48 :: 84 : 13.4

A remarkable coincidence, as if proving that water is incapable of removing the inorganic portion of plants, until the organic matter has undergone such a change as to allow the ash to separate.

From the above, the loss sustained by barley in malting may be stated thus:—

Water, ……………

6.00

Saline matter, ..

0.48

Organic matter,

12.52

 

19.00

At the request of the Editor, who was desirous of ascertaining the amount of soluble matter extracted from malt by mashing, Mr. E. E. HOLDEN, performed an experiment on the small scale, but as proportional with ordinary operations as possible, and found that, on repeatedly treating it with water, at an average temperature of 15oฐ Fahr., 14.5 per cent. of residue, technically termed brewer’s draff, was obtained, showing a loss of 85.5 per cent., water included, or 300 pounds per quarter of malt.

The composition of fresh draff—brewer’s grains—is thus given by FROMBERG:—

 

Centesimally

represented.

Water, ………………………………………..

75.85

Gum, ………………………

1.06

Other organic matter, chiefly husk,

21.28

Organic matter, containing

nitrogen-protein compounds, ………

0.62

Inorganic matter, ………………………..

_1.19_

 

100.00

From Mr. HOLDEN’S experiment and FROMBERG’S analysis of the draff, it would appear that, when the mash is properly managed, the whole of the available or useful matters in the malt are dissolved out by the brewer.

The ash left, on burning the draff, consists of:—

 

Centesimally

represented.

Chlorides and sulphates, ……………..

7.60

Phosphates of potassa and soda, ...

2.11

Phosphates of lime and magnesia,

48.00

Silica, …………………………………………

41.51

Loss, …………………………………………..

_0.78_

 

100.00

 


Commentary

In 1826, White’s Directory listed three maltsters in Bourne but without addresses. One may have used the malt house in Eastgate, mentioned in T.W.Mays’ booklet (Footnote 15). In 1835, Pigot’s listed two, respectively in West Street and North Street. In 1841, Pigot’s listed four, respectively in Market Place, West Street, West Street and North Street. In 1882, White’s listed four: in Market Place, West Street, West Street and North Street; plus others in nearby villages.

The most notable malt house was the one now occupied by Warners (Midlands), in West Street, near Manor Lane. John Gibson lived in West Street on the corner of the present St. Peter’s Road. His malt house was probably the building adjoining St. Peter’s Road, or the southern part of it, which is now demolished.

Footnotes

1. ^    Farina is the Latin name for flour: Langenscheidt gives it as meal, flour; quality of material, character. It has been used as a trade name for a breakfast food made from flour. Here, Muspratt will mean the starchy part of the grain.

2. ^   Saccharine: here = sugary.

3. ^   Acescent: it begins to be sour, that is to say, acidic.

4. ^   Depurate: free it from impurities.

5. ^   Radicle: that part of the embryo of a plant which develops into the primary root (OED).

6. ^   Plumula: the stem of the embryo plant (OED).

7. ^   Carbonic acid: the acid produced by dissolving carbon dioxide in water. In other words, the embryo plants give out CO2.

8. ^    It is the grain which is deprived of its skin!

9. ^     Unmanageable (OED).

10. ^ Aromatic oil, producing the taste or smell of burnt organic matter (OED).

11. ^  This probably refers to Holden’s findings.

12. ^ Exsiccation = the action of drying what is moist (OED).

13. ^  In other words, when soft water is used, the water contains is no chemical base (loosely speaking, alkaline component) which might tend to neutralize the acid.

14. ^ Given life (OED, I.1.).

15. ^  Ure: probably Andrew Ure (1778-1857), a Scottish chemist who published his Dictionary of Chemistry in 1831. To see his article on beer make a search for Beer and select page 202.

16. ^ William Littell Tizard was a brewer at the Nine Elms Brewery, Vauxhall. In 1850, he published a book of which the long title was ‘The Theory and Practice of Brewing Illustrated: containing the chemistry, history, and right application of all brewing ingredients and products; a full exposition of the newly-discovered principles of conversion and extraction in the mash-tun; the philosophy of climate, season, and site; critiques of the modus operandi of fermentation, and the prevention of early acidity: also, many new practical observations on brewing London and Dublin porter, East India pale ale, export stout, &c. &c.’ He had formerly been operative brewer at the Nine Elms Brewery, Vauxhall, and by 1850 was a brewers' engineer. See item 42 on the Book Daemon site: http://bookdaemon.com/catalogT2.html. Accessed: 2011-01-04. (Archived by WebCite at http://www.webcitation.org/5vUhhr4IM)

17. ^ Carbonic acid gas is the old name for carbon dioxide. Some twenty years later, it would be going out of use. OED’s earliest note of the term ‘carbon dioxide’ comes from 1878 (OED, dioxide) but ‘dioxide’ had already been introduced ten or so years before, in 1847 (OED, dioxide), in connection with metallic compounds of oxygen.

18. ^ The Maltsters Association of Great Britain web site describes working with a modern version of this sort of equipment.

19. ^ This will be Joseph Proust. He died in 1826 and OED (hordein) quotes W. Henry as referring, in 1823, to his work on the subject. While working in Madrid (1789-1808 Chambers) he worked on the production of sugar, notably from grapes. By the early nineteenth century, the British blockade of French ports was making the importation of cane sugar difficult, so it looks as though Proust was working on finding means of producing sugar from home-grown sources (French Wikipedia). Perhaps he looked at malt.

20.^  Peculiar principle = one of the constituents of a substance as obtained by chemical analysis (OED: principle, sb. 11 c.) that belongs exclusively to an individual thing (OED: peculiar,  A. adj. 1.).  See Wiktionary adjective 2. That body = starch.

21. ^ Proximate principle: in this case, a chemical constituent (of barley) which is the next, nearest thing (OED, proximate 1) to starch.

22. ^ Centesimally represented = shown calculated according to percentage (OED, centesimal A 3.).

23. ^ Nowadays, the term is replaced by potash (OED. potash) which means potassium carbonate, K2CO3. (Yule. potash). Davey used potassa to designate potassium monoxide, K2O (OED. potassa) but in the early nineteenth century, it sometimes meant the hydroxide or hydrate of potassium, KHO i.e. K2H2O2. (OED. potassa). At this stage, chemists were still trying to understand what they were dealing with.


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