Thanks Chris.
I was definitely not thinking of closing it tight, more like covering with alu foil and making some holes in it.
Basically, the water would boil, some vapour will escape through the small holes and some will actually condensate against the foil and get back into the pan.
At least that's what I would be hoping for...
In your analogue, it would be something like boiling water in a kettle as opposed to a frying pan
I run the wsm wth very little hot coals to start off with and after a 6 or 7 hour cook I still got more than half of the coals left.
I'm quite sure that it's my ambient temperature that causes some of the issues. In the summer, the shade temperature is around 42-45 oC (somewhere around 110 F).
You don't really want to know the temperature in the full sun.....
Ann -
Do you think it is possible you have an unintended air leak somewhere. I'd think the most likely spot would be the side door. Despite the warm climate you live in it seems unusual that closing the vents doesn't provide more heat control. Despit the fact people suggest you leave the leave the lid vent shut, have you ever experimented with closing it a quarter to a half on hot summer days? Just a couple thoughts - best of luck.