Wood tannins are naturally occurring acid chemicals found in tree sap. They can remain dormant in dry wood and be reactivated when wood gets wet.

If wood is painted with products not specifically designed to trap tannins, the tannins can bleed through to the surface resulting in brown, tan or yellow stains. Discoloration can also occur if wood is not fully dry when it’s painted. Staining is most common in redwood, cedar, and mahogany, however, tannin staining can occur with any kind of wood.

To help remove the discoloration, first, wash off the tannin stain, use SuperDeck^® Revive^®, following the label directions carefully.

When internal moisture is the cause, the moisture source must be located and corrected. Allow the surface to dry thoroughly. Check to be sure the water has not affected the adhesion of the coating (e.g., primer, paint or stain).

Seal the stains with an alkyd/oil primer or a coating designed to trap these tannins.

Note that even with proper preparation and recommended products, tannin bleed can still occur, especially on new wood, with either latex or oil topcoats.

Be sure to visit our lead information page for tips on staying safe during restoration projects requiring preparation prior to paint application.

Sherwin offers a wide variety of products to help combat problems with tannin in your finished projects. From premium products for interior surface preparation and design like Cashmere^® and SuperPaint^® all-in-one paint and primer to durable exterior finishes including Duration^® and WoodScapes^® Solid Color Stain, there's a product to help guarantee a long-lasting and beautiful coat on your wood surfaces.