Do Wood Pellets go Bad or have a Shelf Life?

There are many different uses for wood pellets, from being used as a heating fuel in stoves and boilers to the very popular use of BBQ wood pellets. If you’re not familiar with what a pellet is and how they are made you may be asking yourself the question, ‘do wood pellets go bad?’

With this post, I hope to answer that question, as its a more complicated question than most people probably think. The most basic answer is yes, wood pellets can ‘go bad’. However, with this post, I want to talk about the various ways a wood pellet can ‘go bad’. Also what causes pellets to go bad and how to stop it happening.

Finally, I’ll also discuss something that most people are not aware of, some wood pellets are just plain bad, to begin with. So I’ll discuss how you can test pellets to see if they were badly made.

Wood Pellets Gone Bad
The wood pellets on the left have ‘gone bad’ from absorbing moisture, where the wood pellets the on the right still have a good density.

Why can a Wood Pellet go Bad?

There are two main enemies that cause a wood pellet to go bad and that’s moisture and rough handling. I’ll discuss each of them under the subheadings below.

Moisture Absorption

Now, you actually need some moisture to make a wood pellet, however, once the wood pellet has been formed moisture is its enemy. Due to the highly compressed state of a wood pellet and their low moisture content (below 10%) they are naturally seeking out moisture to absorb. That’s why pellets make a such a good animal bedding product for horses.

Therefore, if you don’t keep wood pellets dry, they will absorb moisture and expand. Once expanded they are no longer pellets, just sawdust, and can no longer be used in pellet stoves, boilers and grills.

It’s important to note the main risk to a wood pellet from moisture is not from liquid water. Its water in the air (humidity) which causes pellets to go bad.

Rough Handling

Wood pellets are fairly durable, however, too much rough handling will cause them to break apart and create excessive fines and dust. This dust can cause some pellet stoves, boilers and grills to become blocked up. Therefore, in my post on the top BBQ grill pellet brands, I discuss sieving the wood pellets before they are placed into the hopper.

Can Traeger Wood Pellets go Bad?

Yes, a Traeger wood pellet can go bad if they not protected from moisture and with poor handling. Traeger wood pellets are made in a very similar fashion to others. In terms of leaving BBQ pellets in the hopper of your Traeger pellet grill and going bad, it depends on where you store the grill. Storing the Traeger grill in a garage or shed with pellets in the hopper during the summer months will be fine.

Traeger wood pellets can go bad
Some Traeger wood pellets come in resealable bags where others do not. If you don’t protect your Traeger wood pellets from moisture they will go bad.

However, leaving pellets in the hopper over winter when you’re not using the grill its highly likely they will absorb moisture. Therefore at the end of the grilling season, you should empty the pellets out and store them in a sealed plastic bag. That way you will able to use those barbeque pellets again next year no problem.

How do you Stop Wood Pellets going Bad?

So, to maintain the shelf life of a wood pellet the first issue to address is moisture. Pellets typically come in plastic bags to protect them from moisture. However, what if you don’t use the whole bag in one go? Some stove brands state to never use a previously opened bag of pellets in a stove. This advice is given by Clarry and their portable pellet stove.

Reseal or Tie Open Bags of Wood Pellets

Some BBQ wood pellets such as those from Traeger come in resealable bags. If the bags aren’t resealable you can use a cable tie or wire ties to close up the bag. Also, if there are any tears in the bags make sure to use some tape to cover up the holes.

Keep Wood Pellets in a Low Humidity Environment

So, resealing bags is good, however, if you store them in a high humidity environment moisture could still get into the wood pellet through small gaps. Therefore, try not to store your wood pellet bags in a damp garage or shed, they may still go bad.

Be Gentle when moving your Wood Pellet Bags

Now, good quality wood pellets will not break apart easily when moved around, however, you don’t want to be too rough. Being too rough will increase the percentage of fines/dust in the bags. Another reason to be gentle is otherwise you may tear a bag, and then there are the issues of moisture penetration.

Some Wood Pellets are just Bad to Begin With

Up until now with this post, we have been discussing how to keep a wood pellet from going bad. However, some wood pellets are just made poorly in the first place. For heating fuel, there are various wood pellet grades. These grades will test the ash content of the wood pellets, but also their moisture content and density.

How to test if a Wood Pellet is Bad?

There are a couple of quick little tests you can do see if you have good or bad pellets:

Place the Wood Pellets in a Glass of Water

The most basic test is to take some pellets and drop them in a glass of water. If the pellets sink to the bottom they have been produced to a high density, and can generally be regarded as a good pellet with regards to compression.

Glass of water test
Wood pellets that sink in a glass of water still have a good density and have not gone bad.

You have to be quick with this test though, as they will instantly start to absorb the moisture. Also, don’t leave the wood pellets and water in the glass (like I did). As they absorb the moisture they will expand. The expanded pellets in the bottom of the glass were quite hard to get out. I had to use a knife to scrape out the material, I just couldn’t get it out with my fingers.

The Snap Test

The second test is what I call the ‘snap test’. You want to pick up a wood pellet and place horizontal force on it. A good wood pellet will break into just two pieces with a ‘snap’ sound you should be able to hear. A bad wood pellet will crumble into several pieces and produce small bits and dust, as shown in the diagram below:

Snap Test
The ‘snap’ test will show if the wood pellets were produced to a high density and durability and whether they are good or bad.

The Shine Test

This is the simplest of all the tests, you just need to look at the wood pellet. However, it’s not the most conclusive, therefore I would always still perform a Snap Test to judge them as good or bad.

Shine Test
If there is a shine then the natural lignin within the wood was melted to properly bind the pellets together.

A good wood pellet has a nice smooth surface, with minimal if any cracks. A shiny pellet is the sign of a good quality product. A dull pellet with surface cracks indicates its not as durable and therefore probably a bad batch of pellets.

Do Pellets have a Shelf Life?

So you now know that a wood pellet can go bad if they are not protected from moisture and are handled too roughly. But what about their shelf life? Even in ideal conditions will a wood pellet eventually break apart?

Well, I’ve still got a small sample of the first wood pellet I made back in 2007. They have been kept in a plastic container with the lid on. These pellets still have a nice surface shine with no cracks. They even still pass the snap test. Therefore, if you are able to keep wood pellets away from moisture they don’t have a shelf life. They will maintain their integrity and density.

My first good quality pellets
These are the first ‘good’ wood pellets I made back in 2007, and even today in 2019 they still have a good surface shine.

Conclustion on Wood Pellets going Bad and their Shelf Life

So in conclusion, if you protect your wood pellets from moisture and handle them with care they won’t go bad and can have an unlimited shelf life. If you would like to learn how a wood pellet is made I’ve got various posts for you to read. I also have lots of articles on burning, cooking and the various other uses for wood pellets, just check my homepage and search box at the bottom. Thanks for reading šŸ™‚

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