411 



MALT; MALTING. 



MALT ; MALTING. 



degrees, of being beaten out under the hammer (mo#es, Lat.), or 

 laminated between rollers. The following table represents the order 

 of malleability : 



Gold. 



Silver. 



Copper. 



Platinum. 



Palladium. 



Aluminum. 



Zinc. 



Iron. 



Tin. 



Lead. 



Cadmium. 



Nickel. 



Cobalt. 



Gold is usually cited as an extreme case of malleability. It is. 

 beaten to the 290,000th part of an inch in thickness, and often much 

 thinner than thia, even to the 367,650th of an inch, or about 1200 

 times thinner than ordinary printing paper, and even thia is not the 

 limit of malleability, although there are practical difficulties in the way 

 of further reduction. Comparing equal weights of gold and silver, it 

 will be found that silver can be made to cover a larger surface than 

 gold, so that silver is really more malleable than gold, although the 

 leaf cannot be beaten out so thin. The metals lithium, potassium, 

 and sodium, as well as frozen mercury, admit of being extended under 

 the hammer. 



In the production of sheet-metal, the hammer has been to a great 

 extent superseded by rollers. Iron, steel, and copper, are best rolled 

 red-hot ; zinc is most malleable between 300 and 400 ; most of the 

 other metals and alloys are rolled in the cold state. The rolling-mill 

 performs its work in a more uniform and gradual manner than the 

 hammer, and at the same time developes to the utmost the hardness, 

 tenacity, elasticity, and ductility of such metals and alloys as admit of 

 being rolled. During the process, the condensation is such that brittle- 

 ness would be produced unless the process of annealing were resorted 

 to at intervals. In rolling the thinnest sheets of metal, a number of 

 them are often sent through the rollers at the same time. In some 

 cases, gold and silver leaf for example, the metals are rolled as thin as 

 they will economically admit of, after which the hammer is resorted 

 to. Leaf iron has been rolled into sheets, the 2500th of an inch in 

 thickness, and a square inch of the leaf weighed only three-quarters of 

 a grain. 



The difference between malleability and ductility is noticed under 

 DUCTILITY. In both processes the particles seem to glide along each 

 other's surface, and " the external layers of the metals are retarded or 

 kept back, as it were, in a wave, whilst the central stream or substance 

 continues its course at a somewhat quicker rate. The necessity for 

 annealing occurs, when the compression and sliding have arrived at 

 the limit of cohesion ; beyond this the parts would tear asunder, and 

 produce such of the internal cracks and seams met with in sheet metal 

 and wire, as are not due to original flaws and air-bubbles which have 

 become proportionably elongated in the course of the manufacture of 

 these materials." Holtzapffel's ' Mechanical Manipulation.' 



MALT ; MALTING. Malt is made from all kinds of grain and from 

 rice, but in England almost always from barley, for the use of brewers 

 and 'distillers. It consists of grain which has become sweet and more 

 soluble in water from the conversion of its starch into sugar by artificial 

 germination to a certain extent, after which the process is stopped by 

 the application of heat. The barley is steeped in cold water for a 

 period which (as regulated by law) must not be less than 40 hours , 

 but beyond that period the steeping may be continued as long as is 

 thought proper. Here it imbibes moisture, and increases in bulk ; at 

 the same time a quantity of carbonic arid is emitted, and a part of the 

 substance of the barley is dissolved by the steep- water. The proportion 

 of water imbibed depends partly upon the barley, and partly on the 

 length of time that it is steeped. From the average of a good many 

 trials, it appears that the medium increase is about 47 per cent, ii 

 weight, and 20 per cent, in bulk. The carbonic acid emitted while the 

 barley ia in the steep is inconsiderable ; and it is probable, from the 

 experiments of Saussure, that it owes its formation, at least in part, to 

 the oxygen held in solution by the steep-water. The steep-water 

 gradually acquires a yellow colour. The quantity of matter which i 

 holds in solution varies from J^th to jj^th of the weight of barley 

 This extractive matter is obviously derived from the husk of the 

 barley, and is that substance to which the barley owes its colour 

 Accordingly grain becomes much paler by steeping. 



After the grain has remained a sufficient time in the steep, the wate 

 in drained ofl', and the barley thrown out of the cistern upon the malt 

 floor, where it is formed into a heap called the conch, about 16 inche 

 deep. In this situation it is allowed to remain about 26 hours. It is 

 thin turned by means of- wooden shovels, and diminished a little in 

 depth. This turning is repeated twice a day or oftener, and the grain 

 is spread thinner and thinner, till at last its depth does not exceed a 

 few inches. When placed in a couch, it begins gradually to absorl 

 oxygen from the atmosphere, and to convert it into carbonic acid, a 

 first very slowly, but afterwards more rapidly. The temperature, a 

 first the same with that of the external air, begins slowly to increase 

 and in about 96 hours the grain is at an average about 10 hotter than 

 the surrounding atmosphere. At this time the grain, which hac 

 become dry on the surface, becomes again so moist that it will wet th 

 hand, and exhales at the same time an agreeable odour, not unlike tha 

 of apples. The appearance of this moisture is called rweatiny. A sma] 



ortion of alcohol appears to be volatilised at this period. The great 

 bject of the maltster is to keep the temperature from becoming 

 xcessive, which is effected by frequent turning. The temperature 

 vhich it is wished to preserve varies from 55 to 62, according to the 

 ifferent modes of malting pursued. 



At the time of the sweating, the roots of the grains begin to appear, 

 t first like a small white prominence at the bottom of each seed, which 

 oon divides itself into three rootlets, and increases in length with very 

 jreat rapidity, unless checked by turning the malt. About a day after 

 he sprouting of the roots, the rudiments of the future stem, called 

 acrospire, may be seen to lengthen. It rises from the same extremity 

 if the seed with the root, and advancing within the husk, at last issues 

 rom the opposite end ; but the process of malting is stopped before it 

 las made such progress. As the acrospire shoots along the grain, the 

 appearance of the kernel, or mealy part of the corn, undergoes a con- 

 siderable change. The glutinous and mucilaginous matter is taken up 

 ind removed, the colour becomes white, and the texture so loose that 

 t crumbles to powder between the fingers. The object of malting is 

 .o produce this change : when it is accomplished, which takes place 

 when the acrospire has come near to the end of the seed, the process is 

 stopped by drying the malt upon the kiln. The temperature at first 

 does not exceed 90 ; but it is raised very slowly up to 140 or higher, 

 according to circumstances. The malt is then cleared, to separate the 

 ootlets, which are considered injurious. 



Barley, by being converted into malt, generally increases two or 

 three per cent, in bulk ; and loses, at an average, about 20 per cent, in 

 weight, of which 12 are ascribed to kiln-drying, and consist of water, 

 which the barley would have lost had it been exposed to the same 

 temperature : so that the real loss does not exceed 8 per cent. The 

 roots appear, from the process, to be formed chiefly from the mucila- 

 ginous and glutinous parts of the kernel. The starch is not employed 

 n their formation, but undergoes a change, intended, no doubt, to fit 

 it for the future nourishment of the plumule. It acquires a sweetish 

 taste, and the property of forming a transparent solution with hot 

 water. In short, it approaches somewhat to the nature of sugar, and is 

 probably the same with the sugar into which starch is converted by 

 boiling it with diluted sulphuric acid. 



The following are the results of Dr. Thomson's analysis of barley and 

 the pale malt made from it : 



Barley. Malt. 



Gluten 3 1 



Sugar 4 16 



Gum 5 14 



Starch 88 69 



100 



100 



In brewing ale, porter, and table-beer, three different kinds of malt 

 are employed, which are known as pale or amber malt, brown or 

 blown malt, and roasted or black malt, sometimes called patent malt. 

 The pale or amber malt yields the saccharine or fermentable extract ; 

 the brown malt is not fermentable, but is employed to impart flavour ; 

 and the roasted malt is employed, instead of burnt sugar, merely to 

 give colouring matter to porter. In the brown and roasted malts the 

 sugar appears to be entirely converted into gum and colouring and 

 extractive matters ; and hence they are incapable of undergoing fer- 

 mentation. The brown malt is subjected to a higher temperature in 

 drying than the pale malt, and by a still further exposure to heat in 

 revolving cylinders or roasters it is converted into black or patent 

 malt. 



Most of the changes which have occurred in the malt trade have been 

 due to the peculiar manner in which the product is subjected to duty. 

 Mr. Tyzard introduced a new arrangement of malting apparatus in 

 1852; and Mr. Plomley, in 1858, devised a mode of making the heat 

 act upon the surface of the malt as well as upon the bottom, in drying ; 

 but the foregoing details will suffice to show the general principle on 

 which the operation is conducted. The excise duty has had the effect 

 both of limiting the quantity made, and of checking any improvements 

 in the making. The malt-duty began in England in 1697, in Scotland 

 in 1713, and in Ireland in 1783. In the hundred years from 1716 to 

 1816 there was scarcely any increase in the quantity of malt made in 

 England ; the measure never departing far from 24 million bushels in 

 a year. This stationary condition, at a time when population was 

 steadily increasing, was attributed partly to an increase in the taste for 

 tea and coffee, but chiefly to the effect of duty and restriction. This 

 duty rose gradually from Gd. in 1702, to 4s. 6d. in 1804; it is now 

 a fraction under 2s. 9d. Since 1830, the quantity paying duty has 

 varied from about 30 to 40 million bushels. In 1859 it was 40,406,447, 

 besides 546,743 bushels exempted from duty on various grounds. The 

 price has varied from 2. 6d. to 10s. 6d. per bushel, during a century 

 and a half, the average being about 4s. 6d. The excise regulations 

 were so very stringent in past years, that the maltsters scarcely knew 

 in what manner to conduct their business. An act, passed to regulate 

 the trade in 1827, contained no fewer than 83 clauses, many of which 

 were difficult of interpretation ; more than 100 penalties under it were 

 enforced in three years, amounting to a sum of 13,500i This was 

 replaced by a better statute in 1830, with numerous but intelligible 

 clauses relating to the gauging of cisterns, the wetting of the malt, 



