Elements of the theory and practice of cookery

407. Where sugar comes from. — There are many kinds of sugar, but the kind we usually mean when we speak of sugar is made from the juice of the sugar-cane. This 25U 260 THEORY AND PRACTICE OF COOKERY juice also contains gluten, which makes it a better food than manufactured sugar is. 408. The sugar-cane. — The sugar-cane is a tropical plant belonging to the family of grasses. It looks like corn, but grows sometimes twenty feet high. The stalk contains a loose, spongy substance, filled, in the grow- ing plant, with sap. About the time that the blossoms appear, the sap becomes sweet and rises in the stalks to feed the ripening plant. The stickiness of the stalks is the sign that the cane is ready to be cut down. Sugar Making and Refining 409. Raw sugar. — The sweet juice obtained by crush- ing the cane-stalks between rollers is boiled to a thick syrup in large copper vessels. As it slowly cools, part of it separates into crystals. The liquid that will not crystallize is called molasses. After draining this off, raw sugar, a coarse, impure, brown product, is left. 410. Experiment to illustrate crystallization. — Dissolve in hot water as much sugar as it will take up. This makes what is called a concentrated solution. Boil this till syrupy. Then hang in it sev- eral pieces of worsted, and let it cool slowly. AVhat forms on the worsted ? This is the method used in making rock candy. 411. Experiment with molasses. — Test molasses with red and with blue litmus paper. Is it acid or alkaline ? Add to a little of the molasses in a test-tube a pinch of baking-soda, and test again. What does this test show? What does the foaming of the molasses show? (§§ 193 and 197.) Soda is used with molasses as it is with sour milk to raise batters. — If only a little molasses is called for by the SUGAR AND SWEETS 261 recipe, enough soda must be used to neutralize this, and as much baking-powder added as is required to make the batter light. 412. Experiments to illustrate the refining of raw sugar. — A. Dissolve some raw sugar in water, and pour it through a fine strainer lined with flannel. Which is clearer, the original liquid or the filtrate ? B. Plug the bottom of a flower pot with a sponge, fill it half full of charcoal, and pour through this the filtrate from the strainer. What has become of the brown coloring matter? Taste the filtrate. Where is the sugar? 413. How sugar is refined. — In the sugar refineries of the United States raw sugar is mixed with hot water, treated with lime to neutralize any acid present, and then filtered, first through flannel, afterward through a bed of charcoal. Next it is boiled in vacuum pans. These are covered vessels from which part of the air is exhausted. Under this reduced air pressure the sugar solution can be evaporated to a thick syrup without danger of burning it. (§ 42.) 414. Trade names of sugars. — Granulated sugar is ob- tained from this syrup by putting it into centrifugal machines, rapidly revolving cylinders which throw out the uncrystallizable part of the syrup, leaving a mass of white crystals. Cut or block sugar, the purest kind, is made by run- ning the syrup into molds, where it hardens. The glistening crystalline cones are then sawed into cubes. An inferior kind of block sugar is made by pressing granulated sugar into cubes. These are more regular