Coffee is a very usable photographic developer for film and paper.
Research carried out @RIT showed that coffee, mint leaves, tree bark and othe rplant extracts were suitable for the purpose.
Shutterbug ran an article in it's September 2003 issue which sparked the interest of some people @the photo.net community.
The recipes that were developed then were ccalled Caffenol or Folgernol and included sevral variations of the original.
Basic Caffenol from the article:
8oz water 4tsp instant cofee 2tsp Na-Carbonate
Caffenol Plus Caffenol + 1 tsp table salt
Caffenol LC (low conrast for mini-film) by Donald Quails
8 oz water, 2tsp coffee, 2tsp carbonate
Bob Fowler has printed some great pics using J&C Classic 200,
I have tested it in FP4+, APX100/400, Arista.EDU 400
Don Quails has tested it in document film (microfilm)