More of storage of Caffenol pre-diluted components

As you know, I dilute each of the three main ingredients at 3x strength and store in stand bottles. It works too, at least for something in the region of 6 weeks. I´ve a hypothesis that the sodium carbonate and the ascorbic acid will keep very well. I can´t see why the first should go off, and the second is often used as a preservative. But the coffee, it will go off sooner or later. I therefore performed a test to see how well the coffee mixture will perform at the end of its useable lifespan. At six or seven weeks it starts to develop mould. I would suspect that in the warm summer this can be shortened by a couple of weeks or more. I developed two films the same evening. Both films developed in developer mixed from the same well matured sodium carbonate and ascorbic acid mixes, but one with the old coffee mixture, and one from a fresh batch of coffee. I used 18 minutes for the old coffee mix, and 16 for the new, both @ 20C/68F. I´ll jump the gun and reveal that I couldn´t quite see much of a difference. Judging from the film edges and the Kodak markings both films were developed to within a hair´s breadth of each other. Meaning that the old coffee most likely had deteriorated somewhat, it had been developed an additional two minutes, but not so much as to have an impact on the end result. Both films were equally easy to scan, I would hesitate a guess that they would perform well when subjected to darkroom enlarging.

A few examples from each film.

TMAX100: Old coffee, as are the other chemicals

TMAX100: New coffee, otherwise "old" chemicals

TMAX100: Old coffee, as are the other chemicals

TMAX100: New coffee, otherwise "old" chemicals

TMAX100: New coffee, otherwise "old" chemicals

I´ll be using the rest of the now 9 week old sodium carbonate and ascorbic acid solutions until empty. I find no reason not to. The coffee mix will most likely keep for a good 6 weeks.

Oh, and I´ve just ordered some Fuji Acros 100, it´ll be fun to see if it performs as well as Reinhold at the Caffenol.blogspot says, and if it compares to my TMAX100 experiences.

Note: All pictures taken with my Kowa Super 66