Ok, I put it on a scale and my stainless steel "Tea Ball" weighs 15 grams.
I fill it with about 1-1/2 tablespoons of coarse ground coffee. Fill my mug with about 12 ounces of water and stick the tea ball in the mug, set the mug on my stove and wait for it to start a slow boil. I knock the tea ball around with my spoon while it's simmering and when the color is right I take it off the stove and remove the tea ball so it can cool down because I drink more than one mug and those tea balls will hold the heat a long time.
Now, 15 grams isn't really ultralight, but it's not too bad and the little tea ball should last a lifetime.
Pros: It's easier than making up little coffee bags with filters, very easy to clean, and it's *Real* coffee.
Cons: It's not as fast as instant because you have to let the coffee brew a bit. Agitating it speeds up the process if you're in a hurry.
I'm pretty picky about my morning coffee, and this is really the best method I've found, and with the exception of some of the high falutin instant coffees, I've tried every method mentioned here.
Personally, I don't think instant coffee really even qualifies as being in the same class as fresh brewed coffee, even if Civet cats have pooped it out first
And yes, I knock the spent coffee out on the ground and spread it out a bit. I don't think that will change the ecology of the forest too much for very long.
Look, these tea balls only cost a couple bucks, and some are surely lighter than others. Mine is pretty heavy duty. You can get them at Wal-Mart, Target, and even in some grocery stores.
If you're already carrying ground coffee instead of instant, then I suggest you try this out at home and decide if it works for you too.
Honestly, if I found something that had a better coffee/weight ratio I'd use it. So if you do try this, and you still have a better method then post it and let me know, cuz I will try it!
And if, by chance, you switch to this method, then let others know too, because then I won't look so eccentric when I'm out backpacking with my friends (most of whom already have decided I am) and I can honestly say that other backpackers recommend this method too