At first I thought you meant some company thought it necessary to dye coffee because it wasn't dark enough. Then I realized you meant putting coffee in the product as a dye.
I think ultra-high roast barley would give fewer side effects than a psychoactive bladder irritant like coffee, they use it in the brewing industry to darken beers without affecting the flavor appreciably while still being about to say it only contains barley, hops, yeast and water.
You're probably better off with just charcoal at that point? Sounds like it's 90% of the way there anyway, and whilst pure carbon charcoal is pretty benign to the gut, some partially charred food products can have unexpectedly high irritation.
At first I thought you meant some company thought it necessary to dye coffee because it wasn't dark enough. Then I realized you meant putting coffee in the product as a dye.
I think ultra-high roast barley would give fewer side effects than a psychoactive bladder irritant like coffee, they use it in the brewing industry to darken beers without affecting the flavor appreciably while still being about to say it only contains barley, hops, yeast and water.
The coffee, and cocoa look good as eyeshadow, and blush. But, your suggestion works for me too!
You're probably better off with just charcoal at that point? Sounds like it's 90% of the way there anyway, and whilst pure carbon charcoal is pretty benign to the gut, some partially charred food products can have unexpectedly high irritation.