The foregoing observations are not to be regarded as hard and fast rules, but they are simply intended to give some indications of the malting process when it proceeds on normal lines; it may be that on account of the presence of damaged corns the piece begins to develop mould by about the tenth day, and it then has to be kept thin and sometimes even loaded on kiln prematurely.
The foregoing observations are not to be regarded as hard and fast rules, but they are simply intended to give some indications of the malting process when it proceeds on normal lines; it may be that on account of the presence of damaged corns the piece begins to develop mould by about the tenth day, and it then has to be kept thin and sometimes even loaded on kiln prematurely.
The malt made for grain distillers, in which a high diastatic activity is required, is manufactured on quite different lines from those above indicated. It is often sprinkled late, and loaded on kiln often in a sodden condition. In some cases sprinkling on kiln is resorted to, but it is doubtful if this leads to the desired object. Other things being equal, the smaller the corns—i.e.the greater number of embryos in a given weight—the higher the diastatic activity of the malt. In selecting a barley for the production of highly diastatic malt, the diastatic power of the original raw grain is a factor of great importance.
Kilning.—When loaded on kiln, malt intended for brewing ale and stout is, if properly withered, in a moribund condition; nevertheless, during the first stages of the kilning process a certain amount of vital activity is manifested, and the malt undergoes mellowing by the action of enzymes on the contents of the endosperm. If the malt be loaded while the rootlets appear fresh on account of the presence of too much moisture, rapid growth of the acrospire ensues, giving rise to overshot corns, known in Germany as “hussars.” To check this the moisture must be rapidly removed by the passage of large volumes of air through the malt. But under such circumstances mellowing does not occur. The ideal conditions of kilning are when the malt has been properly withered on the floors before loading, and, assuming that drying and curing occupy four days, that 25-30% of the moisture be removed very gradually, this occupying the first three days, at the end of which the malt is said to be hand-dry. The thickness at which the malt is spread on the kiln should not exceed 7-8 in., and until hand-dry (that is to say, reduced to a moisture content of 12-15%) it should not be turned; if moved at all (and that only is necessary when reek occurs), it should only be lightly forked. The rate at which the temperature is raised depends largely on the kind of malt to be made and the construction of the kiln. If high flavour and colour are required, these are produced by keeping the malt for several hours near a temperature of 160° F. while it still contains 12-15% of moisture. If more than this amount of moisture be present when the temperature reaches the limit just mentioned, the conditions known as stewing would obtain, with the result that “forced” malt would be produced. A certain amount of colour is produced at the final temperature to which the malt is raised; but when such means are relied upon for the production of the greater part of the colour, reduction of extract and deficiency of flavour follow, the colour being then almost exclusively the result of caramelization of the carbohydrates.
The so-called curing stage constitutes the last part of the kilning process, and the malt must then be turned frequently to ensure uniformity of action. Mechanical turners are exceedingly useful for this purpose. Curing in a drum, as in the so-called pneumatic malting process (see below), also effects satisfactory curing.
The following table will give an idea of the kilning temperatures usually employed for the three kinds of malt mentioned, but it must be remembered that these temperatures are largely regulated by the construction of the kiln and the amount of draught available. In this connexion it may be mentioned that the final curing temperature is not necessarily a criterion of the tint of the malt. A malt may have been finished off at a very high temperature and still be a pale malt, provided the moisture percentage has been sufficiently reduced in the initial stages of kilning.RunningPale Malt.Ale Malt.Amber Malt.1st day temp.90-100°F.90-100°F.90-100°F.2nd ” ”100-120100-120100-1303rd ” ”120-130(10 hrs.)120-130( 6 hrs.)130-150( 6 hrs.)3rd ” ”130-180( 8 ” )130-150(12 ” )150-160(12 ” )3rd ” ”180-190( 6 ” )150-180( 6 ” )160-180( 6 ” )4th ” ”drop to 170(12 ” )180-190(12 ” )180-200(12 ” )4th ” ”190-200( 6 ” )200-220( 6 ” )4th ” ”drop to 180( 6 ” )drop to 190( 6 ” )The average laboratory values obtained from malts of the descriptions after about two months’ storage should be as follows:—RunningPale Malt.Ale Malt.Amber Malt.Extract per standard quarter of 336 ℔95-98 ℔94-96 ℔94-96 ℔Moistureabout 2.0% in each caseDiastatic activity (Lintner)30-3520-308-10Tint (Lovibond 52 series neutral)3-56-820-25
The following table will give an idea of the kilning temperatures usually employed for the three kinds of malt mentioned, but it must be remembered that these temperatures are largely regulated by the construction of the kiln and the amount of draught available. In this connexion it may be mentioned that the final curing temperature is not necessarily a criterion of the tint of the malt. A malt may have been finished off at a very high temperature and still be a pale malt, provided the moisture percentage has been sufficiently reduced in the initial stages of kilning.
The average laboratory values obtained from malts of the descriptions after about two months’ storage should be as follows:—
Metabolic Changes.—All through the malting process metabolic changes are proceeding, in which both carbohydrates and proteïns are concerned. In its resting stage the embryo of a barleycorn is generally free from starch; as soon as germination sets in, however, starch appears in the scutellum, while the amount of sucrose there present increases, these being apparently formed from maltose originating from the action of diastase on the starch of the endosperm. Sucrose also augments in the aleurone layer, but starch is never formed in the aleurone cells. These changes occur when the malt is first loaded on kiln; indeed, at no part of the malting process is there greater physiological activity.
Kilning has been specially studied by J. Grüss, who divides the process into four stages, the first being that at which the temperature limit is 113° F. It is characterized by a continuation of the living processes, especially growth of the acrospire, which, as already stated, proceeds too far if the malt be loaded too wet. In any case the rootlet dies away. The metabolism of the carbohydrates already mentioned is accompanied by that of the nitrogenous constituents, the reserve proteïn of the sub-aleurone layer being attacked by proteolytic enzymes and broken down into simpler compounds. This is a most important matter from the point of view of the brewing value of barley, for the degradation products of the proteïns are necessary constituents of wort as yeast food. Moreover, unless proper modification of these proteïn bodies occurs it is impossible to produce tender malt. A barley which contains a high percentage of reserve proteïn is as a rule unfitted for malting purposes, and indeed, the higher the proteïn content the greater the difficulty the maltster experiences in dealing with it. Proteïn hydrolysis requires the presence of a certain amount of moisture, and if this be removed too rapidly by a forced draught at the early stages of kilning the proteolytic enzymes cannot perform their function. If, on the other hand, the grain be loaded in too moist a condition, and the temperature be raised too quickly, the proteolytic enzymes lose their activity and the proteïns remain for the most part unattacked. When germination is allowed to proceed on the kiln too great degradation of the proteïn occurs, and the malt is liable to produce fretty beers, on account of the presence of an excessive amount of nitrogenous nutritive matter, which leads to the development of disease organisms.
The second stage of the kilning process, according to Grüss, is that at which the temperatures range from 113° to 167° F. The life of the corn is now suspended, but enzymatic processes continue. The starch is further saccharified, and the dividing line of the aleurone layer at the furrow is attacked, as are also the cell walls of the endosperm, which are still intact, these being partially converted into gummy substances. This change, however, also requires the presence of a certain amount of moisture. If too much air be passed through the malt at this stage the above-named dividing partition of the cell walls is not attacked. The air may expand the grain to some extent and produce malt of a low bushel weight, which, however, is not properly modified and cannot give satisfactory results in practice.
During the third stage of kilning, an enzyme, which Grüss claims to have recognized, and which he denotes spermoxidase, is said to exert its activity.
Schönfeld has confirmed the discoveries of Grüss by practical experiments.
Fuel.—The fuel used for drying and curing malt is either anthracite or coke, and the greatest care is necessary in selecting it on account of its liability to contain arsenic, which is to a greater or less extent an invariable constituent of all coal. The fuel used for malting purposes should not contain more arsenic than1⁄20th grain per ℔. Gas coke should on no account be used, unless it has beenproved to be sufficiently free from arsenic; but the best oven coke frequently contains so little arsenic that it may be employed with perfect safety, especially if it be mixed with a proportion (e.g.5%) of milk of lime, which retains the arsenic as calcium arsenate. In Germany malt is, as a rule, dried and cured with hot air, whilst in Great Britain the products of combustion are passed through the malt, as it is believed that they exert a beneficial influence on the flavour. The proportion of fuel used for drying and curing malt varies according to the quality of the fuel and the construction of the kiln, but on an average it may be placed at 50-80 ℔ per quarter.[From Sykes & Ling,Principles and Practice of Brewing(1907), Charles Griffin & Co., Ltd.]Fig.9.—Diagrammatic view of pneumatic malting, showing pneumatic washing and steeping cisterns.Storing.—After the malt has passed through the curing stage it is generally heaped up for a few hours. This is believed to increase its flavour. The malt is then stripped from the kiln, and the rootlets, technically known as the coombs, are removed. Formerly this was effected by workmen treading the malt, who wore heavy boots for the purpose. At the present time, however, the rootlets are usually removed by machinery, special forms of which have been devised for this as well as for dressing and polishing the malt. It is the custom of some maltsters to store malt with the rootlets still attached; but this is an objectionable practice, since malt coombs attract moisture, and the presence of more than 3% of moisture in malt produces the condition known as “slackness.” When the malt is packed in bin it is often covered with a layer of coombs, which then prevent access of atmospheric moisture. Malt, to preserve its good qualities intact, should be stored in bins made as nearly as possible air-tight, and it should never be placed in bin until it is quite cool. It is probably wrong to store malt in bins adjacent to the kilns, where it is kept at a higher temperature than that of the surrounding atmosphere. During storage of the malt a kind of mellowing occurs, the mechanism of which is not understood. It is, however, known by practical brewers that the best results cannot be obtained when new malt is used.Premature Malting.—Several years ago Galland suggested germinating barley in a drum, his idea being to do away with handling of the grain, and also to be independent of changes of atmospheric temperature. The latest development of this system, the so-called Galland-Henning process of pneumatic malting, has been improved by Mr R. Blair Robertson, and a diagrammatic view of the interior of one of these maltings, showing the drums and conical steeping cisterns, is shown in fig. 9.The drums are provided with a perforated channel for the passage of air through the malt, which is packed in the annular space between this channel and outside wall of the drum. Each drum is capable of revolving on its axis, and there are arrangements for passing either moist, saturated or dry air through the malt. The system as now improved is capable of producing some of the best malt, especially if, after germination has been completed in the drums, the green malt is loaded on an ordinary kiln and the initial stages of kilning (see above) conducted in the usual way; the curing, however, may be carried out successfully in a special form of drum.Yield and Weight.—The malting process is attended with a certain amount of loss of dry substance of the barley, as follows:—In the steep1.5to2.0%By respiration on floors and on kilns3.0”5.0%Coombs3.0”4.0%———Total7.5”11.0%In addition to this, barley, as already mentioned, contains from 15 to 20% of moisture, whereas finished malt contains 1 to 2%. The total loss in weight which barley undergoes in the malting process may be put down at from 17 to 28%. Since, however, malt is lighter than barley (and the quantity of both was in former years measured exclusively by volume), it frequently happens that a given number of quarters of barley yields a larger number of quarters of finished malt. When this happens it is usual to speak of an increase having been obtained. At the present time weight replaces measure for both barley and malt, and although it is usual to speak of the quantity of grain in terms of quarters, what is meant is not the measured quarter, but so many weighed standard quarters. The standard quarter for English malting barley is 448 ℔ and for malt 336 ℔. From this it will be seen that when a given number of weighed quarters of barley yields the same number of quarters of finished malt, the actual yield is 75%, and there is then said to be neither increase nor decrease. As a rule, in practical working the yield of malt varies from a 4% decrease to a 10% increase, corresponding to an actual yield on the original barley of 72 to 82.5%.J. Baverstock, an old writer, says that finished malt should weigh one-fifth less than the barley from which it is produced. This corresponds to a malting increase of about 7%, which is a high yield. As a rule, foreign barley will give a greater malting increase than English barley, because, on the one hand, the former usually contains less moisture than the latter, and, further, because there is less loss on the floors by respiration and rootlet growth.The yield of malt from barley may be determined in the laboratory in an extremely simple manner. Since every grain of barley must yield a grain of malt, if we know the respective weights of a definite number of barley and malt grains, provided that this number is large enough to represent the average, then obviously this gives the data requisite for calculating the yield of malt from barley. The number of corns the weight of which is determined for this purpose is usually 1000, and if the weight of this number be determined on several different 1000 corns, the average will closely approximateto the truth. Instead of counting the corns by hand, an instrument may be used for this purpose.If 1000 corns of a barley were found to weigh 42 grammes, and 1000 corns of a finished malt from the same barley 32 grammes, then the yield of malt is (32 × 100)/42 = 76.1, this corresponding to a 1% increase. Assuming that the moisture content of the barley was 15% and that of the finished malt 2%, 100 grammes of malt will contain 2 grammes of moisture, and 76.1 grammes will contain (76.1 × 2)/100 = 1.5 grammes moisture; therefore 76.1 grammes of malt contain 76.1 − 1.5 = 74.6 grammes of dry matter. This was obtained from 100 − 15 = 85 grammes of barley dry substance. Hence 100 parts of barley dry substance will yield (74.6 × 100)/85 = 87.7 corresponding with a loss of dry substance equal to 12.5% of the dry substance of the barley, or with a loss of 10.7% on the barley containing 15% of moisture.The results obtained by this method of laboratory control when it is accurately carried out agree very closely with those deduced from the practical results of weighing the barley, malt and coombs in the malting.Special Malts.—In addition to the kinds of malt considered in what precedes, there are others mostly used for imparting specific flavours and colour to beers and stout. These are crystal malt, imperial malt, brown or blown malt, and black or roasted malt. Crystal malt is grown for a shortened period on the floors, and then placed in a wire cylinder, which is rotated over a fire so that it is dried at a very high temperature. The weight per quarter is from 250 to 280 ℔. Imperial malt is dried off on an ordinary kiln at a final temperature of 240-270° F., but it is not allowed the usual length of time on the withering floor. It is placed on the drying kiln in a layer not exceeding one inch and a half in thickness. A moderate heat from burnt wood is first applied until the bulk of the moisture has been driven off, when the temperature is suddenly raised so that the grains swell some 25% and the malt takes up a strong empyreumatic flavour from the products of combustion. This kind of malt weighs 270-300 ℔ per quarter. Black or roasted malt is prepared by roasting malt in a cylinder. Ford states that perfectly malted corn gives a colour of less intensity and permanence than does partially malted corn, and this has been confirmed by other observers. A certain quantity of the so-called black malt is actually made from raw barley, but this gives a product of inferior flavour. The weight per quarter of black malt varies as much as from 215 to 290 ℔.Valuation.—For the valuation of malt the following determinations are usually carried out: Extract per standard quarter, moisture, diastatic activity by the Lintner process, tint, and matters soluble in cold water. The physical examination of malt is also a matter of importance, inasmuch as direct evidence is obtained thereby of the modification of the malt. Among the methods adopted for this purpose may be mentioned counting the percentage of corns in which the acrospire has grown up to one-half, two-thirds and three-fourths the entire length of the corn. In properly made malt the modification of the endosperm should proceedpari passuwith the growth of the acrospire. The sinker test is also useful when carried out in an intelligent manner. Those corns which sink in water and lie flat are improperly modified. Normal malt has a specific gravity less than water and the corns have equal density throughout; consequently they float horizontally in water. In forced samples the proximal ends are frequently lighter than the distal ends, and the corns float horizontally in water, with the germ directed upwards. The latter, however, may in some cases fill with water, and the corns lie flat or sink. This is a characteristic of over-modified malt. It will be seen from these remarks that it is essential to carry out the sinker test under standard conditions. The modification of the malt may also be determined by means of the diaphanoscope already referred to under Barley.Bibliography.—M. M. W. Baird,Journ. Inst. Brewing(1905), 11, 431; J. L. Baker,Journ. Chem. Soc. Trans.(1902), 81, 1177;The Brewing Industry; J. L. Baker and W. D. Dick,Journ. Inst. Brewing(1905),11, 380; J. Baverstock,Treatise on Brewing and Malting(1824); E. S. Beaven,Journ. Fed. Inst. Brewing(1902),8, 542; R. H. Biffen,Journ. Inst. Brewing(1906),12, 366; Board of Agriculture and Fisheries (Leaflet 149); A. J. Brown,Annals of Botany(1907),21, 79; H. T. Brown and G. H. Morris,Journ. Chem. Soc. Trans.(1890), 57, 458; H. T. Brown and others,Trans. Guinness Research Lab.(1903), vol.—pt. I. (1906), pt. II.; M. Delbrück,Journ. Inst. Brewing(1906),12, 642; Ford,A Treatise on Malting(1849); C. Graham, Cantor Lectures, Society of Arts (1874); J. Grüss,Wochenschrift für Brauerei(1895),12, 1257; (1896),13, 729; (1897),14, 321, 409; (1898),15, 81, 269; (1899),16, 519, 621; (1902),19, 243; W. Johannsen,Résumé. Comptes rendus trav. lab. Carlsberg(1884), 2, 60; A. R. Ling,Brewers’ Journal(1904),40, 741; E. J. Mills and J. B. Pettigrew,Journ. Chem. Soc. Trans.(1882),41, 38; E. R. Moritz,Journ. Fed. Inst. Brewing(1895), 1, 228; E. R. Moritz and G. H. Morris,A Textbook of the Science of Brewing(1891); J. M. H. Munro and E. S. Beaven,Journ. Roy. Agric. Soc.(1900),11, pt. II., 5; T. B. Osborne,Reportof Connecticut Agricultural Experiment Station (1894); H. Stopes,Malt and Malting(1895); W. J. Sykes and A. R. Ling,Principles and Practice of Brewing(1907); H. Van LaerBull. de la soc. chim. de Belgique(1905), 337; R. Wahl,Amer. Brewers’ Rev.(1904), 18, 89.(A. R. L.*)
Fuel.—The fuel used for drying and curing malt is either anthracite or coke, and the greatest care is necessary in selecting it on account of its liability to contain arsenic, which is to a greater or less extent an invariable constituent of all coal. The fuel used for malting purposes should not contain more arsenic than1⁄20th grain per ℔. Gas coke should on no account be used, unless it has beenproved to be sufficiently free from arsenic; but the best oven coke frequently contains so little arsenic that it may be employed with perfect safety, especially if it be mixed with a proportion (e.g.5%) of milk of lime, which retains the arsenic as calcium arsenate. In Germany malt is, as a rule, dried and cured with hot air, whilst in Great Britain the products of combustion are passed through the malt, as it is believed that they exert a beneficial influence on the flavour. The proportion of fuel used for drying and curing malt varies according to the quality of the fuel and the construction of the kiln, but on an average it may be placed at 50-80 ℔ per quarter.
Storing.—After the malt has passed through the curing stage it is generally heaped up for a few hours. This is believed to increase its flavour. The malt is then stripped from the kiln, and the rootlets, technically known as the coombs, are removed. Formerly this was effected by workmen treading the malt, who wore heavy boots for the purpose. At the present time, however, the rootlets are usually removed by machinery, special forms of which have been devised for this as well as for dressing and polishing the malt. It is the custom of some maltsters to store malt with the rootlets still attached; but this is an objectionable practice, since malt coombs attract moisture, and the presence of more than 3% of moisture in malt produces the condition known as “slackness.” When the malt is packed in bin it is often covered with a layer of coombs, which then prevent access of atmospheric moisture. Malt, to preserve its good qualities intact, should be stored in bins made as nearly as possible air-tight, and it should never be placed in bin until it is quite cool. It is probably wrong to store malt in bins adjacent to the kilns, where it is kept at a higher temperature than that of the surrounding atmosphere. During storage of the malt a kind of mellowing occurs, the mechanism of which is not understood. It is, however, known by practical brewers that the best results cannot be obtained when new malt is used.
Premature Malting.—Several years ago Galland suggested germinating barley in a drum, his idea being to do away with handling of the grain, and also to be independent of changes of atmospheric temperature. The latest development of this system, the so-called Galland-Henning process of pneumatic malting, has been improved by Mr R. Blair Robertson, and a diagrammatic view of the interior of one of these maltings, showing the drums and conical steeping cisterns, is shown in fig. 9.
The drums are provided with a perforated channel for the passage of air through the malt, which is packed in the annular space between this channel and outside wall of the drum. Each drum is capable of revolving on its axis, and there are arrangements for passing either moist, saturated or dry air through the malt. The system as now improved is capable of producing some of the best malt, especially if, after germination has been completed in the drums, the green malt is loaded on an ordinary kiln and the initial stages of kilning (see above) conducted in the usual way; the curing, however, may be carried out successfully in a special form of drum.
Yield and Weight.—The malting process is attended with a certain amount of loss of dry substance of the barley, as follows:—
In addition to this, barley, as already mentioned, contains from 15 to 20% of moisture, whereas finished malt contains 1 to 2%. The total loss in weight which barley undergoes in the malting process may be put down at from 17 to 28%. Since, however, malt is lighter than barley (and the quantity of both was in former years measured exclusively by volume), it frequently happens that a given number of quarters of barley yields a larger number of quarters of finished malt. When this happens it is usual to speak of an increase having been obtained. At the present time weight replaces measure for both barley and malt, and although it is usual to speak of the quantity of grain in terms of quarters, what is meant is not the measured quarter, but so many weighed standard quarters. The standard quarter for English malting barley is 448 ℔ and for malt 336 ℔. From this it will be seen that when a given number of weighed quarters of barley yields the same number of quarters of finished malt, the actual yield is 75%, and there is then said to be neither increase nor decrease. As a rule, in practical working the yield of malt varies from a 4% decrease to a 10% increase, corresponding to an actual yield on the original barley of 72 to 82.5%.
J. Baverstock, an old writer, says that finished malt should weigh one-fifth less than the barley from which it is produced. This corresponds to a malting increase of about 7%, which is a high yield. As a rule, foreign barley will give a greater malting increase than English barley, because, on the one hand, the former usually contains less moisture than the latter, and, further, because there is less loss on the floors by respiration and rootlet growth.
The yield of malt from barley may be determined in the laboratory in an extremely simple manner. Since every grain of barley must yield a grain of malt, if we know the respective weights of a definite number of barley and malt grains, provided that this number is large enough to represent the average, then obviously this gives the data requisite for calculating the yield of malt from barley. The number of corns the weight of which is determined for this purpose is usually 1000, and if the weight of this number be determined on several different 1000 corns, the average will closely approximateto the truth. Instead of counting the corns by hand, an instrument may be used for this purpose.
If 1000 corns of a barley were found to weigh 42 grammes, and 1000 corns of a finished malt from the same barley 32 grammes, then the yield of malt is (32 × 100)/42 = 76.1, this corresponding to a 1% increase. Assuming that the moisture content of the barley was 15% and that of the finished malt 2%, 100 grammes of malt will contain 2 grammes of moisture, and 76.1 grammes will contain (76.1 × 2)/100 = 1.5 grammes moisture; therefore 76.1 grammes of malt contain 76.1 − 1.5 = 74.6 grammes of dry matter. This was obtained from 100 − 15 = 85 grammes of barley dry substance. Hence 100 parts of barley dry substance will yield (74.6 × 100)/85 = 87.7 corresponding with a loss of dry substance equal to 12.5% of the dry substance of the barley, or with a loss of 10.7% on the barley containing 15% of moisture.
The results obtained by this method of laboratory control when it is accurately carried out agree very closely with those deduced from the practical results of weighing the barley, malt and coombs in the malting.
Special Malts.—In addition to the kinds of malt considered in what precedes, there are others mostly used for imparting specific flavours and colour to beers and stout. These are crystal malt, imperial malt, brown or blown malt, and black or roasted malt. Crystal malt is grown for a shortened period on the floors, and then placed in a wire cylinder, which is rotated over a fire so that it is dried at a very high temperature. The weight per quarter is from 250 to 280 ℔. Imperial malt is dried off on an ordinary kiln at a final temperature of 240-270° F., but it is not allowed the usual length of time on the withering floor. It is placed on the drying kiln in a layer not exceeding one inch and a half in thickness. A moderate heat from burnt wood is first applied until the bulk of the moisture has been driven off, when the temperature is suddenly raised so that the grains swell some 25% and the malt takes up a strong empyreumatic flavour from the products of combustion. This kind of malt weighs 270-300 ℔ per quarter. Black or roasted malt is prepared by roasting malt in a cylinder. Ford states that perfectly malted corn gives a colour of less intensity and permanence than does partially malted corn, and this has been confirmed by other observers. A certain quantity of the so-called black malt is actually made from raw barley, but this gives a product of inferior flavour. The weight per quarter of black malt varies as much as from 215 to 290 ℔.
Valuation.—For the valuation of malt the following determinations are usually carried out: Extract per standard quarter, moisture, diastatic activity by the Lintner process, tint, and matters soluble in cold water. The physical examination of malt is also a matter of importance, inasmuch as direct evidence is obtained thereby of the modification of the malt. Among the methods adopted for this purpose may be mentioned counting the percentage of corns in which the acrospire has grown up to one-half, two-thirds and three-fourths the entire length of the corn. In properly made malt the modification of the endosperm should proceedpari passuwith the growth of the acrospire. The sinker test is also useful when carried out in an intelligent manner. Those corns which sink in water and lie flat are improperly modified. Normal malt has a specific gravity less than water and the corns have equal density throughout; consequently they float horizontally in water. In forced samples the proximal ends are frequently lighter than the distal ends, and the corns float horizontally in water, with the germ directed upwards. The latter, however, may in some cases fill with water, and the corns lie flat or sink. This is a characteristic of over-modified malt. It will be seen from these remarks that it is essential to carry out the sinker test under standard conditions. The modification of the malt may also be determined by means of the diaphanoscope already referred to under Barley.
Bibliography.—M. M. W. Baird,Journ. Inst. Brewing(1905), 11, 431; J. L. Baker,Journ. Chem. Soc. Trans.(1902), 81, 1177;The Brewing Industry; J. L. Baker and W. D. Dick,Journ. Inst. Brewing(1905),11, 380; J. Baverstock,Treatise on Brewing and Malting(1824); E. S. Beaven,Journ. Fed. Inst. Brewing(1902),8, 542; R. H. Biffen,Journ. Inst. Brewing(1906),12, 366; Board of Agriculture and Fisheries (Leaflet 149); A. J. Brown,Annals of Botany(1907),21, 79; H. T. Brown and G. H. Morris,Journ. Chem. Soc. Trans.(1890), 57, 458; H. T. Brown and others,Trans. Guinness Research Lab.(1903), vol.—pt. I. (1906), pt. II.; M. Delbrück,Journ. Inst. Brewing(1906),12, 642; Ford,A Treatise on Malting(1849); C. Graham, Cantor Lectures, Society of Arts (1874); J. Grüss,Wochenschrift für Brauerei(1895),12, 1257; (1896),13, 729; (1897),14, 321, 409; (1898),15, 81, 269; (1899),16, 519, 621; (1902),19, 243; W. Johannsen,Résumé. Comptes rendus trav. lab. Carlsberg(1884), 2, 60; A. R. Ling,Brewers’ Journal(1904),40, 741; E. J. Mills and J. B. Pettigrew,Journ. Chem. Soc. Trans.(1882),41, 38; E. R. Moritz,Journ. Fed. Inst. Brewing(1895), 1, 228; E. R. Moritz and G. H. Morris,A Textbook of the Science of Brewing(1891); J. M. H. Munro and E. S. Beaven,Journ. Roy. Agric. Soc.(1900),11, pt. II., 5; T. B. Osborne,Reportof Connecticut Agricultural Experiment Station (1894); H. Stopes,Malt and Malting(1895); W. J. Sykes and A. R. Ling,Principles and Practice of Brewing(1907); H. Van LaerBull. de la soc. chim. de Belgique(1905), 337; R. Wahl,Amer. Brewers’ Rev.(1904), 18, 89.
(A. R. L.*)