>You boil water in a pan, toss in the grounds, let it boil for a few minutes and then drink it. (Yes, there's sludge at the bottom.)

We call that "cowboy coffee" where I'm from.

I have tried the gold-fliter sits in the stainless steel travel mug -- too sludgey.

My one-cup espresso pot is too small to sit on my trangia.

I am now using a plastic french-press cup with plunge filter. CafePress brand. Pros: very light, good coffee. Cons: none so far! Good for hotels too.