The Book of Household Management by Mrs. Beeton

well ventilated; confined air, though cool, will taint meat sooner than the midday day sun accompanied by a breeze. With regard to smoking the bacon, two precautions are necessary: first, to hang the flitches where no rain comes down upon them; and next, that the smoke must proceed from wood, not peat, turf, or coal. As to the time required to smoke a flitch, it depends a good deal upon whether there be a constant fire beneath; and whether the fire be large or small: a month will do, if the fire be pretty constant and rich, as a farmhouse fire usually is; but over-smoking, or rather too long hanging in the air, makes the bacon rust; great attention should therefore be paid to this matter. The flitch ought not to be dried up to the hardness of a board, and yet it ought to be perfectly dry. Before you hang it up, lay it on the floor, scatter the flesh side pretty thickly over with bran, or with some fine sawdust, not of deal or fir; rub it on the flesh, or pat it well down upon it: this keeps the smoke from getting into the little openings, and makes a sort of crust to be dried on.