Pieces of oak bark of various shapes passing through a sieve with holes of 7 mm.The outer surface is shiny, less dull, smooth or slightly wrinkled, sometimes with small cracks; often visible transversely elongated lenticles. Inner surface of the cortex with numerous thin longitudinal prominent ribs. In the fracture, the outer crust is granular, even, the inner crust is strongly fibrous, knobby. The color is light brown, light gray, silvery or yellowish-brown. The smell is weak, peculiar, intensifying when the bark is moistened with water.
The taste of water extract is very astringent.