Chestnut Extract 8ozChestnut Extract Chestnut trees grow in many parts of the world and contain a great source of tannin. They dye a warm brown color. This dye is also well known for its ability to dye silk black with the addition of logwood and an iron mordant. Dyeing: Mordanting: use alum mordant at 15% WOF for both protein and cellulose fibers (there is enough tannin in chestnut so mordanting with tannin may not required). Dyeing: Use extract on mordanted fiber at 5