STARCH 885 



stirred up with it. The residuary matter in the sacks or cisterus contains much 

 vegetable albumen and gluten, along with the husks ; when exposed to fermentation, 

 this affords a small quantity of starch of rather inferior quality. 



The above milky liquor, obtained by expression or elutriation, is run into large 

 cisterns, where it deposits its starch in layers successively less and less dense ; the 

 uppermost containing a considerable proportion of gluten. The supernatant liquor 

 being drawn off, and fresh water poured on it, the whole must be well stirred up, 

 allowed again to settle, and the surface-liquor withdrawn. This washing should 

 be repeated as long as the water takes any perceptible colour. At the first turbid 

 liquor contains a mixture of gluten, sugar, gum, albumen, &c., it ferments readily, 

 and produces a certain portion of vinegar, which helps to dissolve out the rest of 

 the mingled gluten, and thus to bleach the starch. It is, in fact, by the action of 

 this fermented or soured water, and repeated washing, that it is purified. After the 

 last deposition and decantation, there appears on the surface of the starch a thin 

 layer of a slimy mixture of gluten and albumen, which being scraped off, serves for 

 feeding pigs or oxen; underneath will be found a starch of good quality. The 

 layers of different sorts are then taken up with a wooden shovel, transferred into 

 separate cisterns, where they are agitated with water, and passing through fine sieves. 

 After this pap is once more well settled, the clear water is drawn off, the starchy mass 

 is taken out, and laid on linen cloths in wicker baskets, to drain and become partially 

 dry. When sufficiently firm, it is cut into pieces which are spread upon other cloths, 

 and thoroughly desiccated in a proper drying-room, which in winter is heated by stoves. 

 The upper surface of the starch is generally scraped to remove any dusty matter, and 

 the resulting powder is sold in that state. Wheat yields, upon an average, only 

 from 35 to 40 per cent, of good starch. It should afford more by skilful management. 



With crushed wheat. In this country, wheat crushed between iron rollers is laid 

 to steep in as much water as will wet it thoroughly ; in four or five days the mixture 

 ferments, soon afterwards settles and is ready to be washed out with a quantity 

 of water into the proper fermenting vats. The common time allowed for the steep 

 is from 14 to 20 days. The next process consists in removing the stuff from the 

 vats into a stout round basket set across a back below a pump. One or two men 

 keep going round the basket, stirring up the stuff with strong wooden shovels, while 

 another keeps pumping water, till all the farina is completely \vashed from the bran. 

 Whenever the subjacent back is filled, the liquor is taken out and strained through 

 hair-sieves into square frames or cisterns, where it is allowed to settle for 24 hours ; 

 after which the water is run off from the deposited starch by plug-traps at different 

 levels in the side. The thin stuff, called slimes, upon the surface of the starch, is 

 removed by a tray of a peculiar form. Fresh water is now introduced, and the whole 

 being well mixed by proper agitation, is then poxired upon fine silk sieves. What 

 passes through is allowed to settle for 24 hours ; the liquor being withdrawn, and 

 then the slimes, as before, more water is again poured in, with agitation, when the 

 mixture is again thrown upon the silk sieve. The milky liquor is now suffered 

 to rest for several days, 4 or 5, till the starch becomes settled pretty firmly at the 

 bottom of the square cistern. If the starch is to have the blue tint, called Poland, 

 fine smalt must be mixed in the liquor of the last sieve, in the proportion of 2 or 



3 Ibs. to the cwt. A considerable portion of these slimes may, by good management, 

 be worked up into starch by elutriation and straining. 



The starch is now fit for boxing, by shovelling the cleaned deposit into wooden 

 chests, about 4 feet long, 12 inches broad, and 6 inches deep, perforated throughout 

 and lined with thin canvas. When it is drained and dried into a compact mass, it is 

 turned out by inverting the chest upon a clean table, where it is broken into pieces 



4 or 5 inches square, by laying a ruler underneath the sake, and giving its surface 

 a cut with a knife, after which the slightest pressure with the hand will make the 

 fracture. These pieces are set upon half-burned bricks, which by their porous capil- 

 larity imbibe the moisture of the starch, so that its under surface may not become 

 hard and horny. When sufficiently dried upon the bricks, it is put into a stove 

 (which resembles that of a sugar-refinery), and left there till tolerably dry. It is 

 now removed to a table, when all the sides are carefully scraped with a knife ; it 

 is next packed up in the papers in which it is sold; these packages are returned into 

 the stove, and subjected to a gentle heat during some days; a point which requires 

 to be skilfully regulated. 



During the drying, starch splits into small prismatic columns, of considerable regu- 

 larity. When kept dry, it remains unaltered for a very long period. When it is 

 heated to a certain degree in water, the envelopes of its spheroidal particles burst, 

 and the farina forms a mucilaginous emulsion, magma, or paste. When this apparent 

 solution is evaporated to dryness, a brittle, horny-looking substance is obtained, quite 

 different in aspect from starch, but similar in chemical habitudes. When the moist paste 



