How do you extract tannin from a bark?

To extract tannin from bark, first, finely grind the bark to increase the surface area. Then, soak the ground bark in hot water or alcohol for several hours or overnight, allowing the tannins to dissolve into the liquid. Afterward, filter the mixture to separate the solid bark from the liquid, which contains the extracted tannins. Finally, you can concentrate the tannin solution by evaporating the solvent if desired.