Does wood stain go bad? Well, a wood stain may not go bad in the way other household goods do, but it does change over time. 

There’re a few factors to consider when determining how long does wood stain lasts.

Wood stains are made with different chemicals that can react to each other, leading to new compounds. This can change the color and the shelf life of wood stain.

In this article, we’ll talk about:

  • Can wood stain go bad or how long does wood stain last? 
  • How to store wood stain
  • How to tell if your deck stain is still usable 
  • How to extend the life of your wood stains 
  • How to dispose of wood stains that have gone bad 
  • The shelf life of various wood stains 
  • How to tell if your wood stain is bad

Does Wood Stain Go Bad?

Yes, wood stain does become unusable after completing its shelf life or if it’s exposed to air, unfavorable temperatures, or improper storage conditions. Manufacturers suggest three years to be the wood stain shelf life, but the actual duration can be double that figure. The shelf life manufacturers state is a mere estimate. Wood stains can last much longer if stored in moderate temperatures inside airtight cans. 

How Long Does Wood Stain Last In a Can?

Wood stains can remain good for as long as six years in the can. While most manufacturer labels indicate a storage life of three years, the number varies according to how and where the oil-based stain is stored. 

As such, you will want to test your stain before disposing of it to see if it’s still sound to make the most of your purchase. This also means you will need to know if your wood finish or deck stain is still usable. This article provides all the information you will need.  

Wood Stain Hardened in a Can—How to Revive it

On some occasions, you may open your leftover can of stain to use on a project, only to find the stain dry. 

While the label may indicate the stain hasn’t reached its expiry date, you won’t be able to revive and recover the stain. When wood stain hardens, it undergoes a chemical process, and the hardening means it has been cured already. There’s no practical way to reverse this state.

Even if the stain has only gelled slightly and you manage to recover some reconstituted, colored liquid, it won’t be the same as the original product. 

The polymerization happens when you store the stain will some air trapped in the can. To prevent this from happening, consider decanting the leftover stain into quart cans filled to the top to leave no room for air before storage. 

Does Unopened Stain Go Bad?

Yes. Stains in unopened cans can go bad due to inappropriate storage conditions. For instance, exposure to sunlight or too cold conditions will likely cause degradation even when the product is unopened. 

Such degradation is avoidable as long as you store the product in a cool, dry place sheltered from direct sunlight. 

Does Stain Go Bad if it Freezes?

Not necessarily. Most stains will remain unaffected due to freezing because freezing doesn’t affect the color.

Oil-based wood stains are resistant to freezing as long as you keep them sealed. Since the products don’t contain water, the oil in their formula will thicken under extremely cold temperatures instead of solidifying. 

On the other hand, a water-based stain freezes and solidifies in subzero conditions but does not necessarily go bad. However, some of the dyes will solidify, and this may affect their applicability.

How to Find the Shelf Life of Wood Stain or Finish

Information regarding the recommended shelf life of individual finishing products and wood stains is usually available on the product’s technical data sheet (TDS). 

Technical data sheets are documents manufacturers provide with their products that list various information regarding the respective products.

A product’s TDS includes product composition, operating requirements, methods of use, typical applications, pictures of the product, and relevant warnings. 

Some manufacturers, such as General Finishes and Varathane, post the technical datasheets for each product on their websites. 

Consider looking up the shelf life information on these websites or the TDS document that comes with your purchase.

The Shelf Life of Various Types of Wood Stains

Like any product category, not all wood stains are created equal. This section looks at the shelf life of three main types of wood stains. 

Water-based stains

As the name implies, water-based have water in their formula. The stains dry faster than oil wood stains. They are eco-friendly and less irritating to use. You also need only water to clean them up.

Water-based wood stains don’t contain any binders in their formula. Instead, they use a water-based finish as the binder, unlike varnish and oil wood stains with organic thinners in their formulation.

However, some newer generations of water-based stain formulations contain acrylic polymers. In any case, the shelf life of a water-based wood stain is three years.

If you store water-based deck stains leftover properly, they will remain usable for about a year in storage.

Oil-based stains

Oil stains are penetrating versions comprising linseed oil or a mixture of linseed oil and varnish binders in their formulation. 

This chemical composition allows oil-based stains to cure more slowly than their water-based cousins, allowing more time for wiping the excess during application. 

The stains come in deeply pigmented and lighter dye variations that make wood grain pop while retaining a natural appearance.  

As a rule of thumb, a new can of oil-based stain will last as long as six years without going bad.

After opening the can, the leftover product can remain usable for three years given good storage conditions. 

Varnish wood stains

Varnish stains resemble oil stains in several aspects, except they dry hard to form a hard topcoat on the wood surface. Oil stains, on the other hand, cure by penetrating the wood pores, and you must wipe off any excess stain on the surface because it would only polymerize and never dry. 

Most varnish stains can last a decade or longer given proper storage conditions. However, the satin-type varnish option tends to break down sooner. 

Once you open the gallon of varnish stain, its shelf life reduces. The product will form large hard chunks at the top when it goes bad.

How to Tell if Your Old Deck Stain is Still Usable

An old deck stain will degrade from exposure to air or temperature extremes. Sunlight, oxygen, and moisture are the primary factors that will degrade deck stains during storage. 

So, you need to store half-used deck stains safely away from direct sunlight and keep them airtight to prevent undue exposure to air, moisture, or sunlight. 

To tell if your deck stain is still usable, start by observing the texture for any change. Usable deck stain should have no indication that it has separated, dried up, turned stringy, or undergone some other noticeable change in texture.

Next, apply the stain on a piece of scrap wood and observe the texture and drying behavior. The stain should be sound if it has no noticeable change in texture and dries normally. 

If your stain has expired, here are the best stain for pressure treated wood that I recommend.

Factors that Cause Old Deck Stain to Degrade

Knowing what factors could cause your deck stain to degrade is the first step to preventing such degradation. Read along to find out how to preserve your deck stain. 

Exposure to air 

Oxygen in the air can react with the ingredients in wood stains leading to irreversible alterations in the products’ chemical structure. Such exposure will likely lead bacteria and moisture to react with the pigments and degrade the stain. 

Exposure to sunlight  

Most deck stains are light-sensitive and do not need to be opened to react to the light. Sunlight can lower deck stain quality even if the can remains unopened. 

The light can cause chemical reactions in the product that leads to degradation and permanent changes in the product’s structure. This is why you need to store the stains in opaque containers away from sunlight.

Moisture exposure 

If you store deck stains with moisture inside the container, it can encourage microbial growth in the can, leading to the breaking of the wood stain.

Extreme temperatures or temperature changes 

Many types of wood stain will remain unaffected by freezing temperatures. However, high temperatures will speed up the decay of your deck stain. In some cases, extreme heat will ruin good wood stains.

Additionally, unregulated temperatures that shift from hot to freezing will cause unfavorable freeze-thaw cycles. Such freeze-thaw sequences damage the chemical structure of your stain.

How to Tell if Your Wood Stain is Bad

Although various manufacturers suggest a three-year shelf life for wood stain, you don’t have to throw away your product once the time elapses. You don’t want to dispose of something that could still serve you for a further three years. 

Consider using these tips to determine if your stain is still usable, and dispose of it only if it can no longer work. 

Look for a change in texture.

When stains decay, the pigments disintegrate and tend to separate from the vehicle (or solvent). If your stain is degraded, its change in texture will be the main visible telltale sign of the problem. 

The wood stain may remain in liquid form. If it’s a gel stain, it will likely still have its jelly-like consistency. However, you should see signs of separation or a texture different from the original product.

The change should be easier to see if the damage has become substantial. Often, the standard wood stain will be stringy or dried up.

However, if there’s only a slight change, then chances are, the pigments have settled at the bottom of the can and need stirring to spread back around the solvent. 

Check for an uncharacteristic smell. 

This method may be less effective if you are dealing with oil-based stains. Even at the onset of degradation, they will still smell like a wood stain. The difference in smell may be so slight that you only detect it if you are a regular stain user. 

On the other hand, water-based wood stains don’t have a strong smell. Any such smell should be an indication that something is not all right. 

Delayed drying time

The third telltale sign of expired wood stain is its drying process. To use this test, first, stir the stain to mix all the pigments settled at the bottom of the container with a stick. 

Next, use a rag or paintbrush to rub some stain on a piece of scrap wood. Cover the wood evenly the same way you would your project. Then leave the stain to soak in the pores for approximately five minutes. 

Wipe the excess stain with a rag and observe. The stain should be dry after 24 hours if it’s still usable. If the wood still feels wet to the touch, sticking to your skin upon touch 24 hours later is probably time to dispose of the stain.

How Long Does Stain Last on Wood?

Exterior wood stains generally last about three to five years on wood due to the effects of sunlight. However, the UV rays tend to shorten the lifespan of stains on wood. 

On the other hand, interior wood can last with stain for more than five years because it’s sheltered from the damaging effects of UV rays. 

How to Make Wood Stain Last Longer on Wood 

The service life of wood stains depends on where the wood is located and the conditions it’s exposed to. Usually, weather conditions and high traffic areas will lead to wood stain wearing out much quicker.

However, you can extend the service life of your stain on wood by applying a protective topcoat after staining. Covering the stained wood surface with a hard-drying topcoat such as polyurethane and lacquer will prolong the stain’s lifespan. 

How to Extend the Lifespan of Your Wood Stains and Finishes 

Knowing the factors that make wood stains and finishes decay is the first step to extending the products’ service life. Read along to learn how to extend the lifespan of your stains and finishes.  

Remove the air from opened cans before storage. 

Oxygen and moisture in the air are the primary enemies of wood stains and finishes. Nearly every finishing product will go bad if you open it and store it with air trapped inside the can.

There’re two ways to deal with this issue.

  • First, you can transfer the leftover wood stain into a smaller can that fills up completely. Then, once you have finished your project and remained with some leftover stain, decant it into a smaller pint or quart can and vacuum-seal it for later use. 
  • The second option is to remove the air from the container. Manufacturers have come up with products that can suck the air out of the can and leave your stain or finish safe. 

One such novel product for eliminating air in an opened stain or wood finish can is Bloxygen. Add this inert air into the can to prevent active air (oxygen) from reaching the stain or finish.

You can buy your Bloxygen preserver from Amazon and spray it into your stain can before storage to do the magic.

Seal the container and keep it airtight 

Wood stains and finishes react to oxygen and undergo a chemical change that renders them unusable. In addition, air introduces moisture and microorganisms such as bacteria that react with wood finishes and stains, damaging them. 

So, you want to ensure you prevent the stain or finish from coming into contact with air when in storage by keeping the cans tightly sealed. After removing the air from the can of used stain or wood finish, the next critical step is to close the lid tightly.

Reentry of air into the can will likely undo the benefits of removing the air from the container in the first place. This means closing the lid and securing it tightly in place. 

Here is a systematic procedure to go about it correctly: 

  • Use a clean cloth to wipe clean the outer rim of the can.
  • Gently screw the lid over the top till it’s tightly sealed.
  • Gently squeeze the container to push the leftover wood stain to occupy every space inside.   

You could also use wax paper or plastic wrap with the screw-on lid type to create an airtight seal. 

Store wood stains and finishes in a cool, dry, and dark place 

Some wood stains and finishes are pretty volatile, and high temperatures can vaporize them. This process can cause the pigment and solvent making up the stain to separate, leading the product to go bad. 

On the other hand, icy conditions will likely freeze water-based stains and cause irreversible damage to finishes. So you want to keep these products in temperature-regulated environments to avoid damaging them. 

The ideal temperature range for storing your wood stain and finishes safely is between 50 and 65°F.

Wood stains are also sensitive to the sun’s UV light and could undergo chemical changes if exposed. Therefore, always store your wood stains in dark places or shelters away from direct sunlight. 

Store wood stains and finishes on high shelving for safety 

Children and pets can drop wood stain cans and loosen the seal on impact or spill them all over the place. To avoid such risks, keep the storage cans on high shelves out of children’s reach. 

How to Dispose of Expired Wood Stains and Finishes 

Most wood stains and finishes are composed of volatile and toxic chemicals that qualify as hazardous materials.

As with any such toxic substance and fire hazards, throwing away the stain or finishing product is prohibited. You can’t empty the leftover stain, paint, or varnish in the sink and toss the paint container in the garbage can. 

If the product has reached the end of its lifecycle, take ut to any nearby hazardous waste disposal center for proper disposal. You may want to read how to dispose of stain for more disposal ways.

FAQs

How long is stain good for?

Wood stain can stay good for much longer if you store it in a temperature-regulated environment and free from air and sunlight exposure. But the recommended shelf life of wood stains, according to manufacturers, is three years.

Does unopened wood stain go bad?

Yes, unopened wood stain can spoil if it’s exposed to direct sunlight. The products contain light-sensitive ingredients that can react with UV light and degrade the wood stain.  

Does Minwax stain go bad?

Yes, you can keep Minwax stain for up to 10 years if not exposed to water or direct sunlight. If the stain will not be used soon, it’s best to store Minwax Stain in a temperature-controlled environment at 50°F with a relative humidity of 40% or less.

Is wood stain durable?

Generally, wood stains don’t form a protective film on the wood surface nor provide a durable surface coating. However, film buildup occurs when you treat wood with stains with binders from the same class as paints and varnishes.

Does wood stain darken?

Yes, the wood stain will produce a darker coloring if you add a second coat of stain after the first has dried completely.  

How long does polyurethane last

Polyurethane will last about 12 months in usable condition after you open its can. We recommend labeling the lid of the opened poly with the date it was unsealed to avoid letting it go bad before use.

How long does deck stain last in the can

Deck stains in unopened cans will last up to 5 or 6 years before they can go bad. Therefore, you need to plan your stain project within that window if you have some new wood stain lying around. 

How long does fence stain last

Fence stain can last for one to eight years but the colors will eventually fade depending on how dark the stain was. Reapply fence stain every two to three years to keep your fence looking great and protect it from the elements.

Does Wood Stain Expire?

If you have some new or leftover stain to store for later use, one question comes to mind: Does wood stain go bad? We hope this article helped answer your question. Old wood or deck stains will go bad sooner if you store them in poor conditions involving direct sunlight, extreme temperatures, or exposure to moisture and air. 

Check out – What Wood Takes Stain the Best

If you have any comments or observations, please share them with us in the comments section.