Lecture delivered in 1904 by W. O’Connor.
In the selection of malts for different classes of beers, there are certain characteristics which are desirable for all purposes, but before entering into detail it is interesting to consider, what in my own brewing days I was not too ready to admit, that the suitability of the malt for special types of beers is of far more importance than any control the brewer may later exert in the mash-tun. The insufficiency of mash-tun restriction on diastase is shown by the observation of Moritz and Morris, that a difference of several degrees in the initial mash temperature produced only small alterations in the types of malto-dextrins, and such wide variations in temperature are not within the practical range of brewing operations. On the other hand kiln restriction of diastase can beexercised to practically any extent in properly constituted modern kilns, without necessitating any increase in colour or other alteration of the constituents of the malt. Speaking generally, the requirements in malt which should be fulfilled for all beers, come under the following heads:—
1, Moisture.
2. Tenderness.
3. Time of saccharification.
4. Absence of forcing.
5. Appearance of skin.
As regards moisture, the customary limit of 3 per cent, is a fair one, but should be considered in connection with the circumstances of each case. The result of several experiments on the increase of moisture during 24 hours rail transit, shows an average of very nearly 1 per cent., and this accession of moisture is proportionately greater as the percentage is lower at the time of despatch. It will, therefore, be seen that malt delivered in the same town showing 3 per cent, would point to inferior conditions of storage to one, after transit by rail, containing 3·5 per cent. The point to bear in mind is that the percentage of moisture at time of mashing is of relatively little importance, as the malt is to be at once mixed with water, and that the important question to be considered is the condition in which it has been stored, as excess of moisture at that stage would cause degradation of the albuminoids.
Tenderness may be considered in connection with time of saccharification, as both show the modification of the starch, or in other words, its state of receptivity to the action of diastase. It is the softening of the cell walls of the starch, that is the measure of the careful growth on the floors, complete withering and skilful kilning, and as such processes properly carried out entail additional expense in malting, it will be seen the danger to which the professional brewer is exposed by the demand for cheap malts, which is especially noticeable in years of bad trade like the present. It is possible to malt grain or, rather, to produce what is often termed malt, at costs differing by 2s. per quarter, in proportion as the floors and kilns are crowded and hurried through in 10 or 11 days or slowly grown, at low temperatures for 14 or 15 days.
The only indication as to which process has been adopted appears to be in the time of saccharification. Many analysts place great faith in the amount of ready-formed sugars, as showing clear proof of forcing, but from the results of full analyses of hundreds of kilns, I have failed to find any regular increase in cases where the floor temperatures have been known to be excessive, and this conclusion has been confirmed in the paper read by Mr. Ling before this Institute during the present session, at least so far as regards the ordinary process for the determination of ready-formed sugars. One objection to results of ready-formed sugars being token as indicative of forcing, lies in the fact that in many seasons, barleys from certain districts show high ready-formed sugars when most carefully malted, and this in cases where the resulting beers are of unusual soundness. The figure at which I should fix the maximum for time of saccharification is, for this year, about 35 minutes; though differences in districts and seasons would sensibly affect the adoption of any standard figure.
Appearance of shin is one of the most deceptive of indications, and though brightness is looked upon by many as showing the high class of the barley that has been employed in manufacture, it is more generally a sign of forcing, as where the malting process has been slowly and adequately carried out, the brightness and bloom are entirely eliminated. I do not contend that colour is no indication of the class of barley used, but that there is a species of brightness called, in barley, “bloom,” which, if present, points to incompleteness in malting. I am sorry that lateness in the season does not permit me to bring you, as I should have wished, samples taken from a floor of malt, and experimentally kilned at the 10th, 11th, 12th, 13th, 14th, and 15th days, as I could have then demonstrated that each successive day lessened the brightness, and, in the opinion of many people, the value of the malt.
The remaining points which apply to selection for particular classes of beer are tint and diastasic power. With regard to the former there is no question that the brewer requires absolute uniformity, choosing in each case the highest tint his trade will permit, as in most cases higher tints mean additional fire, fuller flavour and sounder curing. It is, of course, only where the brewer can depend on absolute uniformity that he does ask for malt of his highest required tint, as colour can always be added (though generally with loss of palate roundness), and not taken out, with irregularities in the other direction. As regards diastasic power, the figures most desirable appear to be 22—27 for mild ales and stouts and 30—35 for pale ales; but even malts of 45 diastasic power have been asked for in connection with bitter beers, following the recommendation of Dr. Moritz that low-kiln restriction with high mash-tun restriction, give high types of malto-dextrins which, being difficult of fermentation, will afford condition during protracted storage and consumption. There appear to be strong objections to this theory being carried to such excess, as an equal mash-tun restriction would necessitate employment of very high temperatures, which are alike bad for extract and peptase action, while absence of kiln restriction prohibits full and proper curing of the malt with a consequent degradation of albumenoids during storage. In conclusion, I would point out that uniformity in tint, diastasic power, etc., cannot be obtained where the entire product of a malting is to be used in one brewery or where the malting is carried on in separate kilns. Malt cannot be made to one pattern of analysis, but when finished must be selected and distributed into bins in accordance with laboratory results, and it is only where kilns adjoin, and each bin is accessible from all kilns, that it is possible to arrive at the required degree of uniformity.
Crescent City Brew Talk 