STARCH. Commercially, there are two kinds of starch, those used for food and those used for manufacturing and laundry purposes. The former are such as arrow-root and corn starch, the latter chiefly made from wheat, rice and potatoes. Large quantities of sago starch arc prepared in India and exported to Europe, and small quantities are made from such fruits as the horse-chestnut.
For such as arrow-root or sago, see articles under those head ings. Corn starch is made principally from maize, which contains about 81 per cent of starch, but many manufacturers prefer that obtained from rice, some of the best in the market being derived. from it. It is manufactured as ordinary laundry starch is, with less acid in its constituent parts.
The manufacture of starch from potatoes is described as fol lows : The potatoes are received in an upper story, weighed and "dumped" into the basement. From here they are carried to a long trough, through which passes a wooden cylinder ; from this project several arms, which slowly revolve, keeping the potatoes constantly in motion, while streams of water continually fall upon the mass, escaping from the bottom. These revolving arms grad ually move the potatoes to one end of the tank. Here they fall into the grater as clean as it is possible to wash them by hand. The grater is an iron cylinder with projecting points which crushes, grinds and pulverizes the potatoes into a pulp. The pulp falls upon a long sieve in motion, and upon this is constantly falling a shower of pure water which washes down through the meshes of the sieve all the starch, nothing being left but the potato skin and the broken walls of the starch cells. This refuse is carried in long spouts out of the building into the river. It is regarded as entirely worthless for any purpose whatever—not fit for manure even. The starch used in solution is carried by other spouts into another portion of the building, and run into large vats like those seen in a tannery. Here in the course of twenty-four hours the starch settles or separates from the water, falling to the bottom. The water is then drawn off by means of faucets, leaving the starch as a semi-solid, pasty mass, which is shoveled up into large boxes, raised by windlass to the upper part of the building, where it is " dumped " into cars and wheeled away over a long platform to the " drying house "—which must be a distance from the other buildings. Here it is thrown upon a floor of " scantlings " nailed down with spaces between each of about 22 inches. The heat coming up from the furnaces in the basement rapidly dries the mass, which, falling apart, drops through to a floor below—the latter having narrower spaces. Falling through several of these floors it reaches at last the receiving boxes a fine powder ready to be put in the casks.
The manufacture of wheat starch is very different in some re spects. It is converted into starch by fermentation of the wheat flour. It is first thoroughly mixed with cold water, and then placed in large round tanks made of plank. Here the tempera ture of the mass is raised, yeast is added, and fermentation is al lowed to take place. This is continued for about two weeks, the workmen giving the tanks an occasional stir up to facilitate the escape of carbonic acid gas, which is formed by the decomposition of the gluten and some of the starch in the process of fermenta tion, When the process of fermentation has been completed the pulp is drawn out of the tanks into vats, which are hollow troughs. Here the stuff in each tank is attacked by four men with paddles, who work it in all directions, as if beating eggs, for some time— for several hours, in fact. After undergoing this " beating" pro
cess, the pulp is then put through two sets of sieves, fitted with straining cloth of the very finest texture. These cloths arrest a portion of the gluten, while the balance of it is held in solution and passes through. The starch is now allowed to settle in the settling vats, which are provided with plugs at intervals down the sides. The workmen in attendance, when the starch is mostly set tled below the upper plug, take it out and allow the supernatant liquid to flow off. In like manner, as the volume of the starch descends to the bottom, plug after plug is taken out, until the starch remains in a pulpy condition at the bottom of the tank. Fresh water is then added, the mass stirred up again, and again allowed to settle, the water being drawn off in the manner de scribed. It requires three such washings to remove the gluten from the starch. The liquid drawn from the starch in process of washing is pumped to an upper floor of the factory, where it passes by .a very slight grade through a series of sprouts or con ductors, which zigzag in and out of tho building, finally discharg ing into a large tank in the yard, the contents of which are very nutritious, and are eagerly purchased by farmers to feed their hogs with. The object of the sprouts in question is to save what starch there may be remaining in the liquid drawn off, and the re sult is often quite considerable, being sometimes as high as 30 per cent. of the whole volume produced. The starch thus saved, however, is of an inferior grade, and is sold to calico manufactu rers mainly for use in their industry. After settling in the tanks, the starch is next put into boxes about four feet long by eight inches wide and about the same height, and having a movable lin ing of ticking. The bottoms and sides of these boxes are pierced in numerous places with gimlet holes, so that the remaining mois ture in the starch pulp can drain off. The boxes are packed full of the moist starch and set away to drain for twenty-four hours, when it becomes a moderately solid mass. It is then taken out of the boxes and broken into squares of a size of about six inches. A car, running on a railway track, is now loaded with these squares of partly dried fecula, and run into a kind of oven or heated chamber. Here the squares are carefully laid upon the sheets of strong blue paper, resting upon the brick floor, through which the heat from below is radiated. A temperature of about two hundred degrees Fahrenheit is maintained in the apartment all the time. It takes a week in this room to thoroughly desic cate the starch, at the end of which time the blocks have become disintegrated or broken up into columnar. forms so familiar to all users of starch. After thus being completed in its various pro cesses, the starch is loaded into• the car and brought out of the packing room, where it is put up for the market in packages of various kinds, principally in boxes and barrels, and appropriately numbered and marked. A barrel of flour will produce generally about one hundred and ten pounds of starch. The product is of three qualities ; the first—which is over 50• per cent. of the total volume used—being laundry starch. The second is a standard grade, used for the finer kinds of manufacturers' work, and the third, or sprout starch, has already been mentioned. It takes about four weeks to complete the process of starch making from wheat, from the time of mixing the flour until the starch is ready to pack.