Page:Popular Science Monthly Volume 23.djvu/613

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THE CHEMISTRY OF COOKERY.

action of radiant heat, projected toward it from all sides, while it is immersed in an atmosphere saturated with its own vapors.

Herein I diverge from my teacher, as the preceding description of both his roaster and roasting-oven shows. His explanation of the prejudice of Englishmen against baked meats may have been to some extent justified by his own experience, seeing that he heated his ovens by a fire placed below, and, if he first used these without his water-pan, they doubtless effected the decomposition of the dripping and gravy of which he speaks (see No. XI of this series, page 591); but even in this case the flavor of merely burned fat is not very serious—far less objectionable than that of the vile mixture of vapors described in No. X.

The few domestic fireplace ovens that existed in Rumford's time were clumsily heated by raking some of the fire from the grate into a space left below the oven. Those of the best modern kitcheners are heated by flues going round them, generally starting from the top, which thus attains the highest temperature. The radiation from this does the "browning" for which Rumford's blow-pipes were designed.

According to my view of the philosophy of roasting, this browning, or the application of the highest temperature, should take place at the beginning rather than the end of the process, in order that a crust of firmly coagulated albumen may surround the joint and retain the juices of the meat. All that is necessary to obtain this effect in a sufficient degree is to raise the roasting-oven to its full temperature before the meat is put in. Supposing an equal fire is maintained all the while, this initial temperature will exceed that of the continuing temperature, because, when the meat is in the oven, the radiant heat from its sides are intercepted by the joint and doing work upon it; heat can not do work without a corresponding fall of temperature. While the oven is empty, the radiations from each side cross the open space to re-enforce the temperature of the other sides.

Is there, then, any difference at all between roasting and baking? There is. In roasting, the temperature, after the first start, is maintained about uniformly throughout; while, in baking by the old-fashioned method, the temperature continually declines from the beginning to the end of the process; but, in order that a dweller in cities, or the cook of an ordinary town household, may understand this difference, some explanation is necessary. The old-fashioned oven, such as was generally used in Rumford's time, and is still used in country houses and by old-fashioned bakers, was an arched cavity of brick, with a flat brick floor. This cavity is closed by a suitable door, which, in its primitive and perhaps its best form, was a flat tile that was pressed against the opening, and luted round with clay. Such ovens were, and still are, heated by simply spreading on the brick floor a sufficient quantity of wood—preferably well-dried twigs; these, being lighted, raise the temperature of the arched roof to a