Popular Science Monthly/Volume 24/December 1883/The Chemistry of Cookery VII
|THE CHEMISTRY OF COOKERY.|
I FIND that Sir Henry Thompson, in a lecture delivered at the Fisheries Exhibition, and now reprinted, has invaded my subject, and has done this so well that I shall retaliate by annexing his suggestion, which is that fish should be roasted. He says that this mode of cooking fish should be general, since it is applicable to all varieties. I fully agree with him, but go a little further in the same direction by including, not only roasting in a Dutch or American oven before the fire, but also in the side-ovens of kitcheners and in gas-ovens, which, when used as I have explained, are roasters, i. e., they cook by radiation, without any of the drying anticipated by Sir Henry.
The practical housewife will probably say that this is not new, seeing that people who know what is good have long been in the habit of enjoying mackerel and haddocks (especially Dublin Bay haddocks) stuffed and baked, and cods' heads similarly treated. The Jews do something of the kind with halibut's head, which they prize as the greatest of all piscine delicacies. The John Dory is commonly stuffed and cooked in an oven by those who understand his merits.
The excellence of Sir Henry Thompson's idea consists in its breadth as applicable to all fish, on the basis of that fundamental principle of scientific cookery on which I have so continually and variously insisted, viz., the retention of the natural juices of the viands.
He recommends the placing of the fish entire, if of moderate size, in a tin or plated copper dish adapted to the form and size of the fish, but a little deeper than its thickness, so as to retain all the juices, which by exposure to the heat will flow out; the surface to be lightly spread with butter and a morsel or two added, and the dish placed before the fire in a Dutch or American oven, or the special apparatus made by Burton, of Oxford Street, which was exhibited at the lecture.
To this I may add that, if a closed oven be used, Rumford's device of a false bottom, shown in Fig. 3, of No. 11 of this series, should be adopted, which may be easily done by simply standing the above-described fish-dish, with any kind of support to raise it a little, in a larger tin tray or baking-dish, containing some water. The evaporation of the water will prevent the drying up of the fish or of its natural gravy; and, if the oven ventilation is treated with the contempt I have recommended, the fish, if thick, will be better cooked and more juicy than in an open-faced oven in front of the fire.
This reminds me of a method of cooking fish which, in the course of my pedestrian travels in Italy, I have seen practiced in the rudest of osterias, where my fellow-guests were carbonari (charcoal-burners) wagoners, road-making navvies, etc. Their staple magro, or fast-day material, is split and dried codfish imported from Norway, which in appearance resembles the hides that are imported to the Bermondsey tanneries. A piece is hacked out from one these, soaked for a while in water, and carefully rolled in a piece of paper saturated with olive oil. A hole is then made in the white embers of the charcoal fire, the paper parcel of fish inserted and carefully buried in ashes of selected temperature. It comes out wonderfully well cooked, considering the nature of the raw material. Luxurious cookery en papillote is conducted on the same principle, and especially applied to red mullets, the paper being buttered and the sauce enveloped with the fish. In all these cases the retention of the natural juices is the primary object.
I should say that Sir Henry Thompson directs, as a matter of course, that the roasted fish should be served in the dish wherein it was cooked. He suggests that "portions of fish, such as fillets, may be treated as well as entire fish; garnishes of all kinds, as shell-fish, etc., may be added, flavoring also with fine herbs and condiments according to taste." "Fillets of plaice or skate, with a slice or two of bacon—the dish to be filled or garnished with some previously-boiled haricots"—is wisely recommended as a savory meal for a poor man, and one that is highly nutritious. A chemical analysis of six-pennyworth of such a combination would prove its nutritive value to be equal to fully eighteen-pennyworth of beefsteak.
Some people may be inclined to smile at what I am about to say, viz., that such savory dishes, serving to vary the monotony of the poor hard-working man's ordinary fare, afford considerable moral as well as physical advantage.
An instructive experience of my own will illustrate this. When wandering alone through Norway in 1856, I lost the track in crossing the Kyolen fjeld, struggled on for twenty-three hours without food or rest, and arrived in sorry plight at Lorn, a very wild region. After a few hours' rest I pushed on to a still wilder region and still rougher quarters, and continued thus to the great Jostedal table-land, an unbroken glacier of five hundred square miles; then descended the Jostedal itself to its opening on the Sogne fjord—five days of extreme hardship, with no other food than flatbrod (very coarse oatcake), and bilberries gathered on the way, varied on one occasion with the luxury of two raw turnips. Then I reached a comparatively luxurious station (Ronnei), where ham andand claret were obtainable. The first glass of claret produced an effect that alarmed me—a craving for more and for stronger drink, that was almost irresistible. I finished a bottle of St. Julien, and nothing but a violent effort of will prevented me from then ordering brandy.
I attribute this to the exhaustion consequent upon the excessive work and insufficient unsavory food of the previous five days; have made many subsequent observations on the victims of alcohol, and have no doubt that overwork and scanty, tasteless food are the primary source of the craving for strong drink that so largely prevails with such deplorable results among the class that is the most exposed to such privation. I do not say that this is the only source of such depraved appetite. It may also be engendered by the opposite extreme of excessive luxurious pandering to general sensuality.
The practical inference suggested by this experience and these observations is, that speech-making, pledge-signing, and blue-ribbon missions can only effect temporary results, unless supplemented by satisfying the natural appetite of hungry people by supplies of food that is not only nutritious, but savory and varied. Such food need be no more expensive than that which is commonly eaten by the poorest of Englishmen, but it must be far better cooked.
Comparing the domestic economy of the poorer classes of our countrymen with that of the corresponding classes in France and Italy (with both of which I am well acquainted), I find that the raw material of the dietary of the French and Italians is inferior to that of the English, but a far better result is obtained by better cookery. The Italian peasantry are better fed than the French. In the poor osterias above referred to, not only the Friday salt fish, but all the other viands, were incomparably better cooked than in corresponding places in England, and the variety was greater than is common in many middle-class houses. The ordinary supper of the "roughs" above named was of three courses: first a minestra, i. e., a soup of some kind, continually varied, or a savory dish of macaroni; then a ragout or savory stew of vegetables and meat, followed by an excellent salad; the beverage a flask of thin but genuine wine. When I come to the subject of cheese, I will describe their mode of cooking and using it.
My first walk through Italy extended from the Alps to Naples, and from Messina to Syracuse. I thus spent nearly a year in Italy, during a season of great abundance, and never saw a drunken Italian. A few years after this I walked through a part of Lombardy, and found the little osterias as bad as English beer-shops or low public-houses. It was a period of scarcity and trouble; "the three plagues," as they called them—the potato-disease, the silk-worm fungus, and the grape-disease—had brought about general privation. There was no wine at all; potato-spirit and coarse beer had taken its place. Monotonous polenta, a sort of paste or porridge made from Indian-corn meal, to which they give the contemptuous name of miserabile, was then the general food, and much drunkenness was the natural consequence.
Referring to No. 17 of this series (November "Monthly"), a correspondent who has just returned from Norway, where he followed the route of my last trip there, reminds me of the marvelous congregation of sea-birds that assembles on some of the headlands of the Arctic Ocean, and suggests that egg-oil might be obtained in large quantities there. He quotes from the work of P. L. Simmonds on "Waste Products" the following: "In the Exhibition of 1862 the Russian Commission showed egg-oil in large quantities and of various qualities, the best so fine as to far excel olive-oil for cooking purposes"; but it was not sufficiently cheap for general use.
Among the places indicated by Mr. Grimwood Taylor, the most remarkable is Sverholt Klubben, a grand headland between the North Cape and Nord Kyn, rising precipitously from the sea to a height of above one thousand feet. The face of the rock weathers perpendicularly, forming a number of ledges about two or three feet above each other, and extending laterally for more than a mile. On the two occasions when I passed it, the whole of this amphitheatre was occupied by a species of gull, the "kittiwake," perched on the ledges, their white breasts showing like the shirt-fronts of an audience of a million or two of male pygmies in evening dress. On blowing the steam-whistle, the rock appeared to advance, and presently the sky was darkened by a living cloud, and every other sound was extinguished by a roar of wings and the harsh, wailing screams of a number of birds that I dare not estimate. The celebrated bird colony on the Bass Rock is but a covey compared with this.
The inhabitants of the little human settlement in the Bay of Sverholt derive much of their subsistence from the eggs of these birds; but whether they could gather a few millions for oil-making, without repeating the story of the goose and the golden eggs, is questionable. The eider-ducks that inhabit some of the low mossy islands thereabout, are guarded by strict legislative regulations during their incubation period, lest they should emigrate, and the down-harvest be sacrificed.
I now come to the subject of stewing, more especially the stewing of flesh food. Some of my readers may think that I ought to have treated this in connection with the boiling of meat, as boiling and stewing are commonly regarded as mere modifications of the same process. According to my mode of regarding the subject, i. e., with reference to the object to be attained, these are opposite processes.
The object in the so-called "boiling" of, say, a leg of mutton is to raise the temperature of the meat throughout just up to the cooking temperature (see Nos. 3 and 4) in such a manner that it shall as nearly as possible retain all its juices; the hot water merely operating as a vehicle or medium for conveying the heat.
In stewing nearly all this is reversed. The juices are to be extracted more or less completely, and the water is required to act as a solvent as well as a heat-conveyer. Instead of the meat itself surrounding and enveloping the juices as it should when boiled, roasted, grilled, or fried, we demand in a stew that the juices shall surround or envelop the meat. In some cases the separation of the juices is the sole object, as in the preparation of certain soups and gravies, of which "beef-tea" may be taken as a typical example. Extractum Carnis, or "Liebig's Extract of Meat," is beef-tea (or mutton-tea) concentrated by evaporation.
The juices of lean meat may be extracted very completely without cooking the meat at all, merely by mincing it and then placing it in cold water. Maceration is the proper name for this treatment. The philosophy of this is interesting, and so little understood in the kitchen that I must explain its rudiments.
If two liquids capable of mixing together, but of different densities, be placed in the same vessel, the denser at the bottom, they will mix together in defiance of gravitation, the heavy liquid rising and spreading itself throughout the lighter, and the lighter descending and diffusing itself through the heavier.
Thus, concentrated sulphuric acid (oil of vitriol), which has nearly double the density of water, may be placed under water by pouring water into a tall glass jar, and then carefully pouring the acid down a funnel with a long tube, the bottom end of which touches the bottom of the jar. At first the heavy liquid pushes up the lighter, and its upper surface may be distinctly seen with that of the lighter resting upon it. This is better shown if the water be colored by a blue tincture of litmus, which is reddened by the acid. A red stratum indicates the boundaries of the two liquids. Gradually the reddening proceeds upward and downward, the whole of the water changes from blue to red, and the acid becomes tinged.
Graham worked for many years upon the determination of the laws of this diffusion and the rates at which different liquids diffused into each other. His method was to fill small jars of uniform size and shape (about four ounces capacity) with the saline or other dense solution, place upon the ground mouth of the jar a plate-glass cover, then immerse it, when filled, in a cylindrical glass vessel containing about twenty ounces of distilled water. The cover being very carefully removed, diffusion was allowed to proceed for a given time, and then by analysis the amount of transfer into the distilled water was determined.
I must resist the temptation to expound the very interesting results of these researches, merely stating that they prove this diffusion to be no mere accidental mixing, but an action that proceeds with a regularity reducible to simple mathematical laws. One curious fact I must mention, viz., that, on comparing the solutions of a number of different salts, those which crystallize in the same forms have similar rates of diffusion. The law that bears the most directly upon cookery is that "the quantity of any substance diffused from a solution of uniform strength increases as the temperature rises." The application of this will be seen presently.
It may be supposed that, if the jar used in Graham's diffusion experiments were tied over with a mechanically air-tight and water-tight membrane, brine or other saline solution thus confined in the jar could not diffuse itself into the pure water above and around it; people who are satisfied with anything that "stands to reason" would be quite sure that a bladder which resists the passage of water, even when the water is pressed up to the bursting-point, can not be permeable to a most gentle and spontaneous flow of the same water. The true philosopher, however, never trusts to any reasoning, not even mathematical demonstration, until its conclusions are verified by observations and experiment. In this case all rational preconceptions or mathematical calculations based upon the amount of attractive force exerted between the particles of the different liquids are outraged by the facts.
If a stout, well-tied bladder that would burst rather than allow a drop of water to be squeezed mechanically through it be partially filled with a solution of common washing-soda, and then immersed in distilled water, the soda will make its way out of the bladder by passing through its walls, and the pure water will go in at the same time; for if, after some time is allowed, the outer water be tested by dipping into it a strip of red litmus-paper, it will be turned blue, showing the presence of the alkali therein, and, if the contents of the bladder be weighed or measured, they will be found to have increased by the inflow of fresh water. This inflow is called endosmosis, and the outflow of the solution is called exosmosis. If an India-rubber bottle be filled with water and immersed in alcohol or ether, the endosmosis of the spirit will be so powerfully exerted as to distend the bottle considerably. If the bottle be filled with alcohol or ether and surrounded by water, it will nearly empty itself.
The force exerted by this action is displayed by the rising of the sap from the rootlets of a forest giant to the cells of its topmost leaves. Not only plants, but animals also, are complex osmotic machines. There is scarcely any vital function—if any at all—in which this osmosis does not play an important part. I have no doubt that the mental effort I am at this moment exerting is largely dependent upon the endosmosis and exosmosis that is proceeding through the delicate membranes of some of the many miles of blood-vessels that ramify throughout the gray matter of my brain. But I must wander no further beyond the kitchen, having already said enough to indicate that exosmosis is fundamental to the philosophy of beef-tea extraction, and reserve further particulars for my next paper.
Postscript.—I feel bound to step aside from the proper subject of these papers to make public acknowledgment of an act of honorable generosity, especially as many hard things have been said concerning American plagiarism of the work of British authors. As everybody knows, we have no legal rights in America, and any publisher there may appropriate as much of our work as he chooses. American legislators are responsible for this. Nevertheless, I received, a short time since, a letter from Mr. E. L. Youmans, of New York, inclosing a check for £20, as an honorarium, in consideration of the fact that these papers are being reprinted in "The Popular Science Monthly." Shortly before this, a similar remittance was sent from another publishing firm (Messrs. Funk & Wagnalls), who have reprinted "Science in Short Chapters." These facts indicate that some American publishers have larger organs of conscientiousness than the present majority of American legislators.
I am told that another American publisher has issued another reprint of "Chemistry of Cookery" without making any remittance; but, as Mr. Proctor would say, "this is a detail."—Knowledge.