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.