CHAPTER VI.

COUNT RUMFORD’S ROASTER.

IN the third volume of his ‘Essays, Political, Economical, and Philosophical,’ page 129, Count Rumford introduces this subject, with the following apology, which I repeat and adopt. He says: ‘I shall, no doubt, be criticised by many for dwelling so long on a subject which to them will appear low, vulgar, and trifling; but I must not be deterred by fastidious criticisms from doing all I can do to succeed in what I have undertaken. Were I to treat my subject superficially, my writing would be of no use to anybody, and my labour would be lost; but by investigating it thoroughly, I may, perhaps, engage others to pay that attention to it which, from its importance, it deserves.’

This subject of roasting occupied a large amount of Count Rumford’s attention while he was in England residing in Brompton Road, and founding the Royal Institution. His efforts were directed not merely to cooking the meat effectively, but to doing so economically. Like all others who have contemplated thoughtfully the habits of Englishmen, he was shocked at the barbaric waste of fuel that everywhere prevailed in this country, even to a greater extent then than now.

The first fact that necessarily presented itself to his mind was the great amount of heat that is wasted, when an ordinary joint of meat is suspended in front of an ordinary coal fire to intercept and utilise only a small fraction of its total radiation.

As far as I am aware, there is no other country in Europe where such a process is indigenous. I say ‘indigenous,’ because there certainly are hotels where this or any other English extravagance is perpetrated to please Englishmen who choose to pay for it. What is usually called roast meat in countries not inhabited by English-speaking people, is what we should call ‘baked meat,’ the very name of which sets all the gastronomic bristles of an orthodox Englishman in a position of perpendicularity.

I have a theory of my own respecting the origin of this prejudice. Within the recollection of many still living, the great middle class of Englishmen lived in town; their sitting-rooms were back parlours behind their shops, or factories, or warehouses; their drawing-rooms were on the first-floor, and kitchens in the basement.

They kept one general servant of the ‘Marchioness’ type. The corresponding class now live in suburban villas, keep cook, housemaid, and parlour-maid, besides the gardener and his boy, and they dine at supper-time.

In the days of the one marchioness and the basement kitchen, these citizens ‘of credit and renown’ dined at dinner-time, and were in the habit of placing a three-legged open iron triangle in a brown earthenware dish, then spreading a stratum of peeled potatoes on said dish, and a joint of meat above, on the open triangular support. This edifice was carried by the marchioness to the bakehouse round the corner at about 11 A.M., and brought back steaming and savoury at 1 P.M.

This was especially the case on Sundays; but there were exceptions, as when, for example, the condition of the mistress’s wardrobe offered no particular motive for going to church, and she stayed at home and roasted the Sunday dinner. The experience thus obtained demonstrated a material difference between the flavour of the roasted and the baked meat very decidedly in favour of the home roasted. Why?

The principal reason was, I believe, that the baker’s large bread-oven contained at dinner-time a curious medley of meats—mutton, beef, pork, geese, veal, &c., including stuffing with sage and onions, besides the possibility of a joint or two that had been hung longer than was necessary for procuring tenderness. The vapours of these would induce a confusion of flavours in the milder meats, fully accounting for the observed superiority of the home-roasted joints.

A little reflection on the principles already expounded will show that, theoretically regarded, a given piece of meat would be better roasted in a closed chamber radiating heat _from all sides_ towards the meat than it could be when suspended in front of a fire and heated only on one side, while the other side was turned away to cool more or less, according to the rate of rotation.

If I agreed with the popular belief in the advantage of open-air exposure to direct radiation from glowing coal, I should suggest that for large joints a special roasting fire be constructed, by building an upright cylinder of fire-brick, and erecting within this a smaller cylinder or grating of iron bars, so that the fuel should be placed between these, and thus form an upright cylindrical ring or shirt of fire, enclosed outside by the bricks, but open and glowing towards the inside of the hollow cylinder, in the midst of which the meat should be suspended to receive the radiation from all sides.

The whole apparatus might stand under a dome, terminating in an ordinary chimney, like a glass-house or a steel-maker’s cementing furnace; or, in this respect, like those wondrous kitchens of the old seraglio at Constantinople, where each apartment is a huge chimney, outspreading downwards, so that the cooks, and their materials and apparatus, as well as the huge fires themselves, are all under the great central chimney shaft.

I do not, however, recommend such an apparatus, even to the most wealthy and luxurious epicure, because I am convinced, not merely from theoretical considerations, but also from practical experiments, that all kinds of meat may be not merely as well roasted in a close oven as before an open fire, but that the close chamber, properly managed, produces _better results in every respect_ than can possibly be obtained by roasting in the open air.

To obtain such results there must be no compromise, no concession to any false theory respecting a necessity for special ventilation, excepting in the case of semi-putrid game or venison, which require to be carbonised and disinfected as well as cooked, and, of course, also demand the speedy removal of their noxious vapours.

Not so with fresh meats. There is nothing in the vapour of beef that can injure the flavour of beef, nor in the vapour of mutton that is damaging to mutton, and so on with the rest. But there is much that can, and does actually improve them; or, more strictly speaking, prevents the deterioration to which they are liable when roasted before an open fire. I will endeavour to explain this.

Carefully-conducted experiments have demonstrated the general law that atmospheric air is a vacuum to the vapour of water and other similar vapours, while each particular vapour is a plenum to itself, though not to other vapours; or, otherwise stated, if a given space, at a given temperature, be filled with air, the quantity of aqueous vapour that it is capable of holding is the same as though this space contained no air at all, nor anything else. But this same space may contain a much smaller quantity of aqueous vapour, and yet be absolutely impenetrable to aqueous vapour, provided its temperature is unaltered.

Thus, if a bell-glass, filled with air, under ordinary pressure, at the temperature of 100° Fahr., be placed over a dish of water at the same temperature, a quantity of vapour, equal to 1/30th (in round numbers) of the weight of the air, will rise into the bell-glass, and there remain diffused throughout. If there were less air, or no air at all (temperature remaining the same), the bell-glass would obtain and hold the same quantity of vapour.

If, instead of being filled with air, it contained at the outset only this 1/30th of aqueous vapour, it would now be an impenetrable plenum, behaving like a solid to aqueous vapour—no more could be forced into it while its temperature remained the same.

But while thus charged with aqueous vapour, there would still be room for vapour of alcohol, or turpentine, or ether, or chloroform, &c. It would be a vacuum to these, though a plenum to itself. On the other hand, if the alcohol, turpentine, ether, or chloroform were allowed to evaporate into the bell-glass, a certain quantity of either of these vapours would presently enter it, and then this vapour would act like a solid mass in resisting the entry of any more of its own kind, while it would be freely pervious to the vapour of water or that of the other liquids.

A practical example will further illustrate this. Some years ago I was engaged in the distillation of paraffin oil, and had a few thousand gallons of the crude liquid in a still with a tall head and a rising condenser. In spite of severe firing, the distillation proceeded very slowly. Then I threw into the still, just above the surface of the oil, a jet of steam. The rate of distillation immediately increased with the same firing, although the steam was of much lower temperature than the boiling oil, and, therefore, wasted much heat. The _rationale_ of this was, that at first an atmosphere of oil vapour stood over the oil, and this was impervious to more oil vapour, but on sweeping this out and replacing it by steam, the atmosphere above the liquid oil was permeable by oil vapour. This principle is largely applied in similar distillations.

Always keeping in view that the primary problem in roasting is to raise the temperature throughout to the cooking heat without desiccation of the natural juices of the meat, and applying to this problem the laws of vapour diffusion expounded in my last, it is easy enough to understand the theoretical advantages of roasting in a closed oven, the space within which speedily becomes saturated with those particular vapours that resist further vaporisation of these juices.

In all open-air roasting, whether by the one-sided fire of ordinary construction or the surrounding fire that I have suggested, convection currents are necessarily at work desiccating and toughening the meat in spite of the basting, though tempered thereby.

I say ‘theoretical,’ because I despair of practically convincing any thoroughbred Englishman that baked meat is better than roasted meat by any reasoning whatever. If, however, he is sufficiently ‘un-English’ to test the question experimentally, he may possibly convince himself. To do this fairly, a large joint of meat should be equally divided, one half roasted in front of the fire, the other in a non-ventilated oven over a little water by a cook who knows how to heat the oven. This condition is essential, as some intelligence is demanded in regulating the temperature of an oven, while any barbarian can carry out the modern modification of the ordinary device of the savage, who skewers a bit of meat, and holds this near enough to a fire to make it frizzle.

Having settled this question to my own satisfaction more than twenty years ago, I now amuse myself occasionally by experimenting upon others, and continually find that the most uncompromising theoretical haters of baked meat practically prefer it to orthodox roasted meat, provided always that they eat it in ignorance.