The Story of a Loaf of Bread

by T. B. Wood

The characters described above are not of any great economic importance. Biffen has shown that such important characters as baking strength and resistance to the disease known as yellow rust behave on crossing in the same way as beard. Working on the lines of the experiment described above he has succeeded in producing several new varieties which in baking strength and in rust resistance are a distinct advance on any varieties in cultivation in this country. His method of working was to collect wheats from every part of the world, to sow them and to pick out from the crop, which was usually a mixed one, all the pure types he could. These were grown on small plots for several years under close observation. Many were found to be worthless and were soon discarded. Others were observed to possess some one valuable character. Amongst these a pure strain of Red Fife was obtained from Canadian seed, which was found to retain when grown in England the excellent baking strength of the hard wheats of Canada and North America. Again, other varieties were noticed to remain free from yellow rust year after year, even when varieties on adjoining plots were so badly infected that they failed to produce seed. Other varieties, too, were preserved for the sturdiness of their straw, their earliness in ripening, vigour of growth, or yielding capacity. Many crosses were made with these as parents. The illustration shows a corner of the Cambridge wheat-breeding enclosure including a miscellaneous collection of parent varieties. The paper bags on the ears show where crosses have been made. From the second generation numbers of individual plants possessing desirable characters were picked out, and the fixed types isolated in the third generation by making cultures from the seed of these single plants. The seed from these fixed types was sown on small field plots, at which stage many had to be rejected because they were found wanting in some character of great practical importance which did not make itself evident in the breeding enclosure. The illustration shows a case in point. It was photographed after heavy rain in July. The weakness of the straw of the variety on the left had not been noticed in the enclosure. The types which approved themselves on the small field plots were again grown on larger plots so that their yield and milling and baking characters could be tested. So far two types have survived the ordeal. One combines the cropping power of the best English varieties with the baking strength of North American hard wheat. It is the outcome of a cross between Rough Chaff and Red Fife. Its average crop in 1911 was 38 bushels per acre as the result of 28 independent trials, and, where the local millers have found out its quality, it makes on the market four or five shillings per quarter more than the ordinary English varieties. The other resulted from a cross between Square Head’s Master and a rust-resisting type isolated from a graded Russian wheat called Ghirka. It is practically rust-proof. Consequently it yields a heavier crop than any of the ordinary varieties which are all more or less susceptible to rust. The presence of rust in and on the leaves hinders the growth of the plant, lowers the yield, and increases the proportion of shrivelled grains. It has been estimated that rust diminishes the world’s wheat crop by something like one third. The new rust-proof variety gave an average yield of about 6 bushels per acre more than ordinary varieties on the average of 28 trials last year. It is called Little Joss and is especially valuable in the Fens and other districts where rust is more than usually virulent.

Fig. 5. Corner of bird-proof enclosure showing a varied assortment of parent varieties of wheat. Crosses have been made on some of them as shown by the ears tied up in paper bags

Fig. 6. Field plots of two new varieties of the same parentage which had approved themselves in the bird-proof enclosure. That on the left had to be rejected on account of the weakness of its straw. That on the right is the rust-proof variety known as Little Joss. The photograph was taken after a storm which in the open field found out the weak point of the one variety

CHAPTER IV
THE QUALITY OF WHEAT FROM THE MILLER’S POINT OF VIEW

To the miller the quality of wheat depends on three chief factors, the percentage of dirt, weed seeds, and other impurities, the percentage of water in the sample, and a complex and somewhat ill-defined character commonly called strength.

With the methods of growing, cleaning and thrashing wheat practised in Great Britain, practically clean samples are produced, and home grown wheat is therefore on the whole fairly free from impurities. This is, however, far from the case with foreign wheats, many of which arrive at the English ports in an extremely dirty condition. They are purchased by millers subject to a deduction from the price for impurities above the standard percentage which is allowed. The purchase is usually made before the cargo is unloaded. Official samples are taken during the unloading in which the percentage of impurities is determined, and the deduction, if any, estimated.

The percentage of water, the natural moisture as it is usually called, varies greatly in the wheats of different countries. In home grown wheats it is usually 16 per cent., but in very dry seasons it may be much lower, and in wet seasons it may rise to 18 per cent. Foreign wheats are usually considerably drier than home grown wheats. In Russian wheats 12 per cent. is about the average, and that too is about the figure for many of the wheats from Canada, the States, Argentina, and parts of Australia. Indian wheats sometimes contain less than 10 per cent. This is also about the percentage in the wheats of the arid lands on the Pacific coast and in Australia. These figures show that home grown wheats often contain as much as 5 per cent. more water than the foreign wheats imported from the more arid countries. The more water a wheat contains the less flour it will yield in the mill. Consequently the less its value to the miller. A difference of 5 per cent. of natural moisture means a difference in price of from 1s. 6d. to 2s. per quarter in favour of the drier foreign wheats. This is one of the reasons why foreign wheats command a higher price than those grown in this country.

Turning to the third factor which determines the quality of wheat from the miller’s point of view, we may for the present define strength as the capacity for making bread which suits the public taste of the present day. We shall discuss this point more fully when we deal with the baking of bread. At present the only generally accepted method of determining the strength of a sample of wheat is to mill it and bake it, usually into cottage loaves. The strength of the wheat is then determined from their size, shape, texture, and general appearance. A really strong flour makes a large, well risen loaf of uniformly porous texture. Wheats lacking in strength are known as weak. A weak wheat makes a small flat loaf. In order to give a numerical expression to the varying degrees of strength met with in different wheats, the Home Grown Wheat Committee of the National Association of British and Irish Millers have adopted a scale as the result of many thousand milling and baking tests. On their scale the strength of the best wheat imported from Canada, graded as No. 1 Manitoban, or from the States graded as No. 1 Hard Spring, is taken as 100, that of the well-known grade of flour known as London Households as 80, and that of the ordinary varieties of home grown wheat, such as Square Head’s Master, Browick, Stand Up, etc., as 65. The strength of most foreign wheats falls within these limits. Thus the strength of Ghirka wheat from Russia is about 85, of Choice White Karachi from India 75, of Plate River wheat from the Argentine 80, etc. The strongest of all wheats is grown in certain districts in Hungary. It is marked above 100 on the scale, but it is not used for bread making. The soft wheats from the more arid regions in Australia and the States are usually weaker than average home grown samples, and are marked at 60. Rivet or cone wheat, a heavy cropping bearded variety much grown by small holders,—since the sparrow, which would ruin small plots of any other variety, seems to dislike Rivet, possibly on account of its beard,—is the weakest of all wheats, and is only marked at 20, which means that bread baked from Rivet flour alone would be practically unsaleable. Rivet wheat finds a ready sale, however, for making certain kinds of biscuits.