- Coffee, either fresh or coffee grounds (You can get FREE coffee grounds from Starbucks who give them away in HUGE bags full of it)
coffee contains tannin, which acts as a natural mordant. A mordant is a substance that chemically interacts with the fiber surface and allows the color to stick to the fiber. Tannin is present in bark, oak galls, and tea of course. By heating the coffee in water, the tannin and brown coloring agents from the coffee go into solution in the dye vat. Then the tannin in the solution changes fiber surface so the brown coloring agents can penetrate the fibers that are being dyed.
Boil water, add coffee, or coffee grounds. Let simmer for a long time. A couple hours, over night, time isn't all that important.
Let the dye bath cool, then strain the dye liquid removing the coffee grounds, then add fabric or fiber.
Bring dye bath back to a simmer, and let simmer for a while. Turn the heat off, let the dye bath and fiber cool in the bath overnight.
Remove fiber, rinse in cool water, then let the fiber dry inside or out of the sun.
Tips for the novice dyer.
Make sure that the fiber or fabric to be dyed is thoroughly wet, and close in temperature to the dye vat. Quick changes in temperature can ruin some fabric, as can prolonged rapid boiling. Wool is particularly sensitive to heat changes, and the combination of heat, tannin and agitation (from a rapid boil) can turn wool fabric into felt.
Start by using equal weights of dye stuff and fabric or fiber should be used. Less coffee, or coffee grounds, will result in light tans, and beiges, while more coffee and greater time will give shades of dark brown.
Always use a nonreactive pots for dyeing. Stainless steel, glass, or enamel without any chips. Iron, copper, or aluminium will interact with the dye with unpredictable results.
Expriment, try combinations of fabric coffee and time, but most of all good luck and enjoy yourself!