TESTING WHEAT

Timaru Herald, Volume CXXXVII, Issue 19750, 17 March 1934, Page 18

TESTING WHEAT

MINIATURE MILL INTERESTING PROCESS Up till about two years ago, wheat for milling purposes was accepted or rejected on its apparent condition. If a line looked as though it would mill into good flour, it was purchased by the miller, but if it was shrivelled or in any way out of condition, the best market that could be found for it was as fowl wheat. To-day, however, and perhaps all farmers are not aware of this. fact, the wheat can be tested both for moisture content, and also in a short space of time, a sample can be converted into flour, and from flour into bread. Throughout the process, statistics are noted, and when the miniature loaf is extracted from the oven, there stands revealed the quality of the original wheat for baking purposes. The Timaru Milling Co. have on their premises in Mill Street, a plant which will carry out the tests which have been referred to, and the process is one of extreme interest. A representative of “The Timaru Herald” was yesterday privileged to visit the mill, and to see the work in progress. In the sample room, if one might be permitted to use the term, were dozens of bags of wheat, small brown paper bags, containing perhaps 51b. of wheat. A member of the staff was busy enteringup the samples in a book, and checking them off for bushel weights. Cleaning the Sample. In order to secure clean flour it is essential to have clean wheat, and to bring about this result, the sample to be tested is first of all cleaned on a wheat cleaning machine, consisting of a double eccentric seive making two separations of large and small impurities. The wheat is subjected to a strong current of air as it leaves the sieves, and any impurities lighter than the wheat are extracted. Beaters revolving at 1.000 revolutions a minute then scour the wheat in a rough cast iron cylinder, and rub off the beard of the grain, and also loosen any impurities which may be adhering to the berries. Another current of air is drawn through the grain as it leaves the scouring cylinder, and after being carefully weighed to 2,000 grams the sample is ready for grinding. Wheat that has a very low moisture content is “conditioned” by adding water to mellow the grain and toughen the bran. The conditioning of a dry sample improves the resultant flour, as the bran becomes of a tougher nature, and does, not powder so easily, which means cleaner flour and a better coloured loaf. Milling the Wheat. The milling of the wheat is done on exactly the same lines as in a large mill, namely the gradual reduction system. The first grinding operation takes place on the first break. This work is done by grooved chilled iron rollers, running at different speeds. The grooves are spiral, running along the length of the rolls, and the action is scissor like, shearing the bran from the endosperm. There are four “breaks” in the system, and at each operation the pieal is graded on a plansifter, which has a rotary motion, similar to a hand sieve. Only a small percentage of flour is made on the breaks, or grooved rolls, their main object being to make a high percentage of good quality semolina and middlings for the reduction or smoother rolls, and on the last or fourth break, to clean up the bran as a finished product. The reduction system is a complication of grinding and grading of semolina and middlings, and the gradual reduction of these stocks into flour. All the flour passes through silk sieves, with a mesh of about 110 threads to the inch The rolls used on the reduction are of chilled iron, but have a smooth surface. They also run at differential speeds. Altogether there are five reductions, and at each operation there is a percentage of the stock sifted away as pollard until all the flour has been extracted. The flour which has been manufactured through the process is all collected in a drawer beneath the plansifter, and is then carefully weighed to determine the percentage of extraction The aim throughout the process is to secure 70 per cent, extraction of flour, 20 per cent, of pollard and 10 per cent, of bran, and in the sample which the “Herald” representative saw yesterday, the percentages were 71, 19 apd 10. Making the Bread. Having secured the flour, the next process is to test its baking quality. This falls to the lot of a young baker, who is kept as busy as his companions, whose job it is to bake the flour. Yesterday he made no fewer than 33 tests, a fairly solid day’s work when one comes to consider the amount of data which has to be collected. For instance, a note has to be made of the quantity of water added; the handling of the dough; oven spring; general appearance of the«Joaf when baked; its bloom, flavour, texture, crumb colour, and pile. The total score of points is 50, but this would be a “baker’s dream.” The standard set is round about 37, and loaves which bake up to between 30 and 35 are considered to be quite good. The data secured in the tests to which the wheat and flour are subjected arc invaluable, and enables millers to procure wheat which they know for a certainty will give a good quality flour In a judgment based on appearance, a miller might reject a line of wheat, but when submitted to the tests detailed, it might turn out a very good line.

In a short time, the “testing” will be going on during the whole 24 hours of the day, and it is estimated that it will take some months, even working round the clock, to overtake the work in hand.