You can make your own portion packs by cutting the toes off a pair of pantyhose. Pour suitable amount of ground coffee in and tie in a knot. Store it in a zip-lock bag. Drop in a pot, add water, boil. With a little luck and care you can reuse the 'filter'. Fine grounds make the coffee a little chunky. I don't mind my coffee a little chunky.

People with delicate dispositions can run the brew through a standard coffee filter to take out the fine grounds.