Foil and slow-roasting

I have mentioned here before the flaw in the theory that covering meat -- with foil or with a lid -- keeps it moist during cooking. It is not the atmosphere that is important, but the temperature and the cooking medium. A build-up of steam will cook meat very efficiently, and dry it out.

The flaw in that theory, I have realised, is that my oven gets pretty hot, even on the lowest setting. The likes of Heston Blumenthal have ovens that they can keep at 70C; mine -- a not inexpensive model -- gets as high as 130C, even on gas mark S. A foil covering for slow cooking is protective. (Here is a slow-cooked belly pork.)

Last weekend, I browned a half-shoulder of lamb. The time was 1.15 p.m. I put the joint into a roasting tin with a little oil, a scattering of rosemary and chopped garlic, and seasoning; I covered the tin with foil, and put it on to the bottom of the oven, at gas mark S.

I turned and basted the meat occasionally. At 5.30 p.m., I parboiled some sliced potatoes, drained them, and tipped them into the tin with the meat, turning them in the fat and the -- surprisingly meagre -- juice. At 6.45 p.m., I took the meat out of the oven, transferring it to a hot plate and leaving it in the warm grill section. I turned up the oven to gas mark 6/200 C and put the tin of potatoes on the top shelf to brown.

That took half an hour, after which the meat was rested and deliciously tender. We ate it with the potatoes and some leeks.