"Ray @ First Rays Orchids" wrote in message ...

I have no idea what the caffeine concentration is

Miniscule, as a percentage by weight. My brain isn't clicking on all
cylinders at the moment, but I think the number is about .08%. (The
amount of caffeine in a 6 oz/240 ml cup of "normal" coffee is
considered to be 200 mg.)

If it works, it works, but I do wonder whether it's really the
caffeine that's doing the working there. IIRC, the University of
Hawaii study found that a 1% solution only deterred the little
buggers, it took a relatively whopping 2% to actually kill them.
Perhaps the snails just prefer tea and go elsewhere when served
coffee.

MG