Caffenol-C-M, recipe. The mix is pretty straight forward:
1 litre water
54 grams washing-soda
16 grams vitamin-C
40 grams coffee
Add the ingredients in the order listed above with constant stirring. Fully dissolve all of one ingredient before adding the next. I mixed with water around 70˚F and all mixed without much trouble. After adding coffee it is suggested you let the mix stand to 5 minutes to let the bubbles disperse and the coffee fully dissolve. I stirred once more before use. Just a warning the smell is not pleasant, image an full ashtray with a cup of coffee poured into it. I shot the T-Max 400 at 100 as Caffenol-C-M is suggested for medium Fast Films. Development time was 15 minutes, but judging from the density of the negatives, 10 minutes may have been fine, but I and still more than pleases with the results.
For further information check out these sites Caffenol and caffenol.