I didn't know l-dopa turned black...I always have had to work with the beans and plants VERY quickly to not have them turn black after being picked. Yes , Ken Allan was the one who "kitchen tested" my fava tincture...sent it all the way to Canada. Isn't it ridiculous not to be able to find a chemistry person to work with here??? By the way, does anyone know if Ken Allan is ok? I haven't heard from him since about May and am concerned. He was a long-distance Mentor for tips on growing the beans in the first place over the computer.