We all know the wonderful MSR Whisperlite is capable of burning water, but even with the latest pump, getting the thing to simmer is a bit of a challenge. Judicious lowering of the pressure in the bottle and careful fiddling with the control valve will eventually allow you to get some control and produce a low(ish) flame, at which point the low(ish) flame will blow out.
Decent pots like the MSR range (especially the hard anodised ones) will help as they spread the heat very well indeed, and their non-stick coating helps a lot. Even then, if you're trying to heat something gently, it's a challenge not to burn the food at the bottom of the pan. If you're trying to use something like Vango's rather nasty stainless steel pots, it's impossible, and forget it if you're using ordinary aluminium pots.
However, there is a solution - and it's to be found in a splendid kitchenware shop called Lakeland. They sell a gadget called a "diffuser" which is intended for use in a domestic kitchen, but will also work rather well on an MSR or any similar stove. It comes in two sizes, 19 cms (large) and 17 cms (small). The large is approx the same size as my MSR cookset and will fit neatly into its bag. Some debate on the forum has also produced a recommendation for a similar one from Kitchencraft, which is a bit cheaper.
MSR fired up, not quite full bore, but near enough. It's running on Aspen 4T chainsaw fuel, which I have found burns very cleanly and is far cheaper than Coleman fuel at around £14 for 5 ltrs compared to Coleman at £7 for 500 mls! Neither does it have the noticable odour of unleaded and is much less smokey when used to preheat. That said, I carry a small bottle of meths for that purpose.
-- and in a few minutes, a nice rolling boil. That output is going to burn anything - and certainly not allow you to heat something without constant stirring.
Drop in the diffuser - - and stick the pot on top - -
- - and even on the same power setting, it never went above this very gentle simmer. I left it for about 10 mins, and it was much the same. Result.
Mike Buckley - March 2010.