Until the present, pure Caffenol is more a curiosity than a possibility. Yes, coffee is a developer agent and needs, like most developer agents an alkali to work. Pure Caffenol has some disadvantages, people using it report stains and large grain sizes on films. So, coffee appears in many recipes linked to Vit. C and small ammounts of potassium bromide in order to make it better. But all the Caffenol variants are not considered fine grain developers. Reinhold, from Caffenol blog, is using now coffee and Vit. C plus sodium sulfite and Rodinal or paRodinal to get a fine grain developer. The results are impressive. One recipe (or two) already have been tested with a 400 ISO Kodak film exposed at 3200 ISO and developed with the new recipe. Fantastic, no grain at all! Congratulations, Reinhold and thanks for sharing this with the world. Also thanks for the mention in your post.