Interesting article on using coffee, tea, or vitamin c as a developer. Caffeine apparently works really well as a developing agent – how cool is that!
Yes, it will take a lot longer (25 minutes for T-Max 400) and more light (rated at ISO 100), but if you’re shooting film I feel like you’re doing it for the satisfaction in making an image by hand as much as possible. Now this just adds to that by controlling the developing process yourself.
Check out the recipe over here at Shutterbug. Seems like there will be some experimenting involved. And you can use water as a stop bath and salt water for a fixer. Would love to see more images (or some 16 mm movies!!) developed with this home brew. Coffee and Celluloid combine!