Uh-oh. There now appears to be brown-colored stains on your painted wooden surface. They weren’t there when it was first painted. What’s happening? It could be tannin stains. And there are ways to try to prevent a wooden surface from getting them! Here we show you how with the help of Boysen products as well as what to do with wood that already has them.

What Causes Tannin Stains on Wood

Tannin stains are caused by, well, tannin. Tannin is a substance that’s naturally occurring in wood. When your wood is exposed to moisture, the tannin bleeds to the surface. And this is when you see it as a brown or tan-colored stain on your wood.

Some types of wood have more tannin than others. Tannin-rich wood like oak and mahogany are more prone to tannin stains. Luckily, plywood, which is a common construction material in the Philippines, is not as tannin-rich and therefore, unlikely to develop tannin stains.

Remember, moisture is one of the main enemies of wood. Moisture in your wood may not only cause tannin stains but can also cause your wood to deteriorate. This is where the importance of paint comes in. Paint—specifically paint made for wood—helps protect wood from moisture to avoid tannin stains and other harmful effects of moisture.

Product Highlight: Boysen WoodPrime - Wood tannin stain

How to Prevent Tannin Stains on Your Wooden Surface

Tannin stains ruin the beautiful look of your wooden furniture and fixtures. How do you prevent them? As mentioned, tannin is naturally inherent in wood. So, to prevent it from showing up on the surface, ensure that no moisture gets into your wood. Paint can help you with this.

Option 1: Choosing the Right Sealers and Primers

There are sealers and primers available that do a great job of serving as a barrier between your wood and moisture that can penetrate it and cause tannin stains. Some are also specially manufactured with anti-tannin properties. We asked the Boysen experts for their recommended products to avoid tannin stains and here are their picks:

Tannin Stains: What to Do About It and How to Avoid It | MyBoysen

Boysen Lacquer Sanding Sealer

If you’re finishing with gloss or flat lacquer on your wooden surface, use Boysen Lacquer Sanding Sealer. It’s a sealer for interior wood furniture, cabinets, doors, and panels. Note: It’s not meant to be used on surfaces that will be walked on or where you expect to place heavy objects on. Find more info here.

Homes in High Humidity Areas: Waterproofing and Painting Guide | MyBoysen

Boysen Acrytex Primer

Boysen Acrytex forms a non-porous, seamless, watertight film that serves as a stain inhibitor for wood and moisture sealant for concrete. Use it for bare interior and exterior wooden and masonry surfaces. As a topcoat for walls and ceilings, use Boysen Acrytex Topcoat or any other water-based paints such as Boysen Permacoat Latex and Boysen Healthy Home. For high-touch areas like cabinets, best stick with Boysen Acrytex Topcoat. Find more info here.

Special Mention: Boysen WoodPrime

Boysen WoodPrime is for when you want to use latex paint (a.k.a. water-based paint) on your wooden surface. The direct application of latex paints on wood is not usually recommended as it is typically easier for moisture to pass through this type of paint.

However, if you are looking for a water-based primer (to avoid the strong chemical odors of solvent-based paints, for instance), Boysen WoodPrime is a good choice. It’s formulated to have better tannin-stain resistance and is low in odor. Upon initial application, a tannin stain may still occur for some species of wood but reapplication should do the trick. Find more info here.

Option 2: Choosing the Right Painting System

Another way to prevent tannin stains is to select a painting system that can protect your wood from moisture and water. For those new to painting, a painting system is a set of products recommended to be used together to achieve best possible intended results. A painting system typically consists of a primer, putty, and topcoat.

Here are some Boysen painting systems you can use for your wood to avoid tannins stains:

Boysen Automotive Lacquer 
Boysen Acrytex

What to Do When Tannin Stains Appear

If tannin stains have appeared on your wood, it may be because you failed to use or apply a tannin-resistant sealer, primer, or paint system. Or, it could also be because your paint is already failing due to deterioration (which can happen over time) which has then caused moisture to seep into your wood.

If you have failed to apply tannin-resistant products, experts advise scraping off all the paint on your wood until you have a bare surface once again. Then, this time around, use the appropriate products or painting system to prevent tannin stains.

If your paint is deteriorating, first check the surface for spots where moisture has possibly been seeping through. Then, repaint your wood paying close attention to the spots you have identified. It may also be a good strategy to strip the surface to bare wood and start over again if the paint has deteriorated too much and there are too many areas where moisture can seep in.

Good luck! If you have any questions on painting or inquiries about Boysen products, our technical team will be happy to assist you. Send an email to ask@myboysen.com or call (02) 8363-9738 local 413 to 418 during office hours for a one-on-one consultation.


Jill is a writer on a continuous journey to learn about paint and share them with you, the reader. She has an interest in the technical side of things but also thoroughly enjoys playing with colors. She likes calm greens, quiet blues, and mellow yellows best.

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