If we now bisect a grain of barley longitudinally—that is, through the ventral furrow—we shall find that the grain consists of two principal parts—(1) the germ or embryo (the part endowed with actual life); (2) the endosperm, the starchy portion of the grain.

Diagram of a Longitudinal Section of a Barley-Corn. A, endosperm; B, germ. a, starch-containing cells of the endosperm; b, aleurone layere; c, absorptive epithelium of the scutellum; d, plumule; e, rootlets; f, scutellum.

The germ, which in the dried barley-corn forms only about one-thirtieth of the whole, is separated from the endosperm by a barrier known as the “scutellum.” This scutellum consists of layers of compressed empty cells; and on the side which is pressed on the endosperm is situated a layer of elongated cells, known as the “absorptive epithelial layer.” These cells have most important functions, and play an important part in the feeding of the young embryo when it commences to develop into a young plant.

The germ consists of two distinct parts—plumule and rootlets. During germination this plumule becomes the acrospire of the malt, and if the seed were sown in the ground and germination pushed on to completion the acrospire would develop into the actual stem of the plant, and, under similar conditions, the rootlets would from the roots.

Section Showing Epithelium (Greatly Magnified). a, Empty compressed starch cells of the endosperm; b, absorptive epithelium; c, starch-containing cells of the endosperm; d, secutellum.

The endosperm consists of a mass of starch-cells, intermingled with irregular and spherical particles of nitrogenous matter, the whole contained in compartments of cellulose, and forming a store of foodstuff to supply the germ until it has grown sufficiently to enable it to draw nourishment through its roots and leaves.

Immediately under the skin is a triple layer of thick-walled square-shaped cells, known as the “aleurone cells.” These cells contain finely granulated nitrogenous matter, and also small spherules of fat or oil. It is not clear what their immediate function is, but, seeing they are in contact with the starch-cells of the endosperm and the bulk of the germ, they may take some active part in the transfer of food from the former to the latter.

Now, although the substances in the endosperm are intended as a food-supply for the germ, they are in an entirely unavailable condition, for, in the first place, the scutellum will prevent the passage to the germ unless theses substances are in a state of solution, and, in the second place, such a solution must be a diffusible one. Now, starch, which constitutes the bulk of the endosperm, is practically insoluble, and the nitrogenous matters are almost entirely so, while such portions of them as do dissolve in water yield non-diffusible solutions.

With the object of rendering the amount of foodstuff available for the young germ, the epithelial layer of the scutellum, which I have previously described, has the property, when sufficient water is present, of secreting soluble ferments, or ensymes, which have the power of acting on the starch and nitrogenous matter and rendering them both soluble, and the solutions of which are diffusible. The enzyme which acts upon starch is diastase, while that which acts upon nitrogenous matter is vegetable pancreatin, and is probably similar to peptase.

Now, although by the aid of the two ferments, diastase and peptase, the two difficulties of solubility and diffusibility are overcome, the foodstuffs in the endosperm aré not even yet available for the nutrition of the germ. I mentioned previously, in speaking of the contents of the endosperm, that both the starch and gluten cells were enclosed within compartments of cellulose, and, as this cellulose tissue is impervious both to diastase and peptase, it is necessary that another enzyme should be secreted to dissolve this cellulose. This enzyme is called “cytase,” and its action, of course, precedes the action of both the other ferments. Cytase is secreted in the region of the scutellum, and slowly passes through the grain, and its passage may be noted by the progressive softening of the corn as it dissolves the cellulose, the original hardness of the grain

being due to this substance. Cytase converts the cellulose into sugar (dextrose), and this, passing through the scutellum, is used by the germ as food.^* The diastase acts upon the now exposed starch and converts it into maltose, no dextrin being formed. The maltose passes from where it is formed in the endosperm to the germ, but, while transfusing, this scutellum is apparently converted into cane-sugar in an unascertained manner. This cane-sugar now formed is used by the germ as food. A portion of it is inverted into invert sugar by an enzyme called “invertase” that is secrweted in the neighbourhood of the rootlets.

While these changes are taking place an analogous process is also going on with the nitrogenous matter. The nitrogenous constituents of malt consist principally of glutens. These are acted upon by the peptase, and are converted into peptones, amides, amido-acids, and albuminoids proper, the former pasing readily through the scutellum and forming the nitrogenous portion of nutriment of the germ.

From the above you will realise what an enormous amount of energy is lying dormant within the germ of the barley-corn, and only waiting the addition of water at a suitable temperature to bring these numerous and complex changes about.

On a commercial scale the process is carried out in the following manner: The barley, after having been thoroughly cleaned by passing through screening machinery, and graded to take out the light, thin corns, is then immersed in water in a large tank known as the cistern. The barley is allowed to soak for about fifty hours; but, of course, this will vary very much according to the nature of the barley and the temperature of the steep-water, which should be from 50° to 55° Fahr. If the water is below this temperature it tends to delay germination.

While in the cistern the barley absorbs about 50 per cent. of water, and its proportions increase considerably in bulk. The lower the initial moisture of the barley the more rapidly does it absorb water. This is a matter of importance, as barley grown on undulating land—as much of the New Zealand barley is—invariably shows great irregularity in the amount of initial moisture; consequently some of the grain absorbs more water than the other while in the cistern, which, in turn, means uneven growth. To remedy this, many maltsters now adopt the system of sweating prior to steeping. By the term “sweating” is meant kiln-drying. The barley, before being stored in bins, is subjected to a temperature of about 100° Fahr. on the

kiln for about eight hours. By this means the amount of moisture is reduced.

During the steeping stage the weater is changed several times, partly because the water dissolves a certain amout of organic matter from the grain which would afford a supply of food for the numerous bacterial organisms that adhere to the barley, and also because the accompanying aeration due to the draining of the barley greatly assists to bring about germination.

The grain having been steeped—that is, sufficiently soaked—it is now laid out upon the growing-floor. It is usual to commence the process by what is known as “couching the malt” for twelve or eighteen hours—that is, keeping it up to a depth of 12in. or 18in.; this allows the heat to accumulate, and starts the act of germination more rapidly than would be the case if the grain were laid out in a shallow piece.

After couching, the next process is flooring. The couch is broken down, and the grain is laid evenly over the floor to the depth of 3in. or 4in. The depth entirely depending upon the temperature, naturally on a warm, muggy day the grain will be spread thinner than on a cold day, and vice versa.

In about twenty-four hours after the removal of the grain from the cistern the rootlets begin to make an appearance in the form of a white protrusion at one end of the barley-corn. On the following day many of the corns will show from one to three distinct rootlets, and on the third day nearly the whole of the grain will have three or four roots. By the third day the acrospire—that is, the stalk part of the germ—will begin to maove up the back of the corn.

During all this time a respiratory process is proceeding—that is, the corn is actually inhaling atmospheric oxygen and exhaling carbon-dioxide, and any undue accumulation of this latter gas either stops its growth or seriously impedes it; provision has therefore to be made for removing the carbon-dioxide and supplying fresh oxygen. This necessary aeration is secured by turning the malt. The turning is effected with broad flat wooden shovels, and as each shovelful is thrown forward a dexterous turn of the wrist scatters it thinly and evenly on the floor in front. This turning usually takes place both morning and evening.

On the fifth or sixth day the roots will begin to probably lose their fresh appearance, and become yellowish, this shows that the piece is becoming deficient in moisture. It is therefore sprinkled with water from a long-spouted watering-can made for this purpose. The amount of sprinkling-water used is usually about half a gallon to the bushel, and the whole of

this is applied during the fifth and sixth days. This should supply sufficient moisture to carry on germination until the acrospire has reached about two-thirds or three-quarters up the back of the corn, when germination has proceeded far enough.

Directly the cellulose has been all converted, all further change in the barley-corn represents dead loss, so that when we have accumulated sufficient cytase to remove the rest of the cellulose tissue, the piece is thickened slightly and allowed to remain for eighteen or twenty-four hours without turning. By this means the growth is to a certain extent stopped, the piece collects heat and loses moisture, and the rootlets become shrivelled in appearance; this part of the process is known as “withering.” On the floors working at the abnove temperatures it will take about twelve days to arrive at the withering stage. Working at a higher temperature, and using a larger quantity of sprinkling-water, it would be possible to obtain the same amount of growth in eight or nine days; but in this case a larger amount of carbo-hydrate and soluble nitrogenous matter is formed in the germ than it has time to assimilate; consequently, these bodies would remain in the malt, and pass over into the brewer's wort, with disastrous results.

During the later stages of growth upon the floors mould will unfortunately begin to make an appearance, the damaged and broken corns being the first attacked. For this reason as many aspossible of the broken corns are removed prior to steeping; but, although broken corns can be mechanically removed, this does not apply to corns that are slightly skinned. Hence, however careful the maltster may be, a certain amount of mould is inevitable. For this the grower is almost entirely to blame, the damage to the grain being either due to setting the threshing-machine too close—and this is frequently done intentionally, so as to break off the awn as short as possible, and so give the barley a plump appearance—or because the grower is anxious to get a large amount of grain threshed in a given time, the machine, in consequence, being driven at too high a speed. It is not too much to say that much of the New Zealand barley is really unfit for malting for this one reason—the grower will not realise that barley for malting should have an awn.

The withering stage having been completed, the grain is now loaded on to the kiln, where it is subjected to two distinct though continuous processes—viz., drying the curing.

The object of drying is twofold—firstly, we want to effectually arrest any further growth in the malt; and, secondly, we want to reduce the percentage of moisture existing at the