I have never tried this so I do not know if it would work but it might be an option. Get the smallest French press available. I have one for a cup or two. Put enough water in for what I want then put in the immersion thingee. I have never used one so have no idea how big it is. Heat up the water in the press. I think the glass should take the heat as you usually put boiling water in them. When hot enough put in the ground coffee and stir. Place the plunger on top and wait until it has brewed to your liking. Plunge, drink, clean out pot. It does mean packing the pot in your luggage but for me I can do without an extra pair of shoes if it means coffee in the morning.