DIY

What Moisture Content Should Firewood Be (And How To Check and season logs)

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When it comes to burning wood in a wood burning stove or open fire, it’s essential that you only use what is known as seasoned wood. Seasoned logs have a low moisture content which means the fire burns efficiently and with dry firewood, you’ll get the best combustion and it gives you the best heat output.

It’s important to note that just adding more wood to a stove will not give more heat. It’s burning the firewood with the correct moisture content with the fire set to the most efficient setting in terms of allowing air into the stove that makes it the most efficient and gives the most heat output.

What moisture content should wood be?

Deciding what moisture content is best for wood for log burning stoves

Firewood moisture content should be between 10% and 20%, any higher and the fire will not be as efficient as it struggles to boil the water content in the logs before it can burn the logs.

It’s worth noting that is now illegal to sell logs with a moisture content higher than 20% unless you sell more than 2 cubic meters of which you have to provide instructions on how to season wood. I also have instructions on how to do this further down.

For anyone with space to buy unseasoned firewood in bulk this can be much more affordable but the downside is it can take between 1 and 2 years to season firewood so the water content is less than 20%.

If you buy firewood in small bags such as from garden centres, petrol stations or even specialist firewood retailers. You will notice it’s now sold as seasoned firewood so it should be ready to use straight away but I always recommend checking the moisture content yourself before burning any logs.

How to measure the moisture content in firewood

Measuring moisture content of firewood using moisture meter

So if you have firewood ready, it’s always a good idea to check if the wood has a moisture content between 10% and 20%. This is easily done by investing in a good moisture meter which cost about the price of a couple of bags of logs so it’s a worthy investment and makes checking the moisture content in wood quick and easy.

Most moisture meters have LCD screen/led indicators which will give a readout of the moisture content. The model I use above just has LED’s that light up green when the moisture content is below 20% and then it goes to amber or red the more moisture there is.

Simply insert the two pins into the firewood (it’s worth noting, there are a few models that do have pins). It will then give a simple readout of the moisture content, ideally between 10-20%. You should also check several sides of the log to get a fair reading.

If the firewood is not fully seasoned then you need to season the firewood for longer until the moisture content is less than 20%.

You can check out my recommended moisture meters for firewood here

Can firewood be too dry?

Firewood can actually be too dry although it’s not very common to get firewood with a moisture content of less than around 8%. If it is too dry, the wood will burn too quickly and cause the flue to cool at the same time and make the fire less efficient. However, you can still burn them, it’s just not as efficient and will burn more quickly.

Read next: If you are having issues lighting your wood burning stove then check out my guide on how to light a wood burning stove using the upside-down method here.

How to tell if the firewood is to dry if you don’t have a moisture meter?

If you don’t have a moisture meter there are a few ways to help you decide if your firewood is probably ready to burn.

Firstly any freshly cut logs will not be ready to burn, hardwood often takes up to 2 years to dry out properly and wood such as pine takes around a year so you will have to season your firewood for at least a year if not longer. Sometimes with pine, it can dry in around 6 months if prepared in spring and stored over summer.

Firewood ready to burn with clear rings, peeling bark

That being said, there are a few ways to help you tell if your firewood is ready to burn as outlined below:

  • The wood should be brown, light coloured and NOT HAVE any greenish tints to it.
  • Its usually much lighter than freshly cut wood which is a giveaway.
  • Seasoned firewood usually has a rough texture rather than smooth.
  • The wood is cracking and the bark peels off easily.
  • If you bang two pieces of wood together it should be loud and ringing. Wood with a higher moisure content is usually a dull sound due to the water content.
  • Should have clear visable rings.

There is also another way called the soap test

Do the blow test to make sure firewood has a low moisture content by adding soap to the end of a log. Blowing from the other side the air should travel through the channels that usually carry water.

Simply apply some soap on the end of the log and blow through the other end of the log like I’m doing above. If bubbles appear in the soap like they are above, this means that the air is passing through the channels the water is usually stored.

This means it is probably ready to use. You wouldn’t need to do this with every piece, just take a few random pieces of wood that were all cut and stored at the same time and test them. If they all pass the blow test then the woodpile is probably all suitable for burning.

How to season firewood at home?

The process of seasoning firewood at home is simple and easy, it just takes a lot longer which is why you need to plan your firewood needs ahead of time. However, if you have access to free logs like I do, it’s well worth seasoning your own firewood as it will save you a lot of money, compared to buying kiln dried logs.

So the first thing you need is a log store, I have actually reviewed some log stores here. You can also make one if you’re handy as they are fairly simple structures. A log store will stop rain from falling directly on the logs but have an open front and often slatted sides and back to allow air to move freely around the logs which is essential for seasoning logs as quickly as possible.

You also want to position your log store so it gets plenty of sun if possible and so that the wind can move freely around and through it as this is what dries the logs out naturally.

How to season firewood

Using a log store to store firewood for 12-24 months to season the wood so the moisture content is below 20%

You got a log store, what next?

Firstly, your logs will dry much more quickly if you cut them up into pieces instead of trying to season full logs. I have been able to season softwood logs in around 6 months by doing this so if you start storing them from spring, you can sometimes have some firewood ready for October as the cold nights draw in. Typically though, it takes around 12 months to 2 years, especially for hardwood logs.

How to prepare logs for seasoning?

Firewood being cut into sizes ideal for stove and to help it season faster

I like to cut my logs around 16 inches long and around 6 to 8 inches thick.

With your wood cut into the perfect size firewood, I then stack them. Now, it’s important to make sure the logs are not stacked on the floor and are raised up a little so air can flow underneath them. Most logs stores are already designed like this but you can also use a couple of longer logs to lay the log stack on so they don’t directly touch the floor.

How to stack logs in a log store?

Make sure you only stack one log thick and stack up to the top of the log store. Thats it, if heavy rain is forecast for long periods of time, you can cover with a tarpaulin to keep the rain off but I find it’s not really needed and this does stop airflow.

If you have issues with blackened glass, check out my guide on how to clean the stove glass with ash here, it is amazingly effective.

If you want to order a log store check this guide out here, also take a look at my recommended log splitters here and log splitting axe review here.

To increase the efficiency of your stove I also recommend getting the valiant stove fan which I review here.


Welcome to my site, my name is John and I have been lucky enough to work in horticultural nurseries for over 15 years in the UK. As the founder and editor as well as researcher, I have a City & Guilds Horticultural Qualifications which I proudly display on our About us page. I now work full time on this website where I review the very best gardening products and tools and write reliable gardening guides. Behind this site is an actual real person who has worked and has experience with the types of products we review as well as years of knowledge on the topics we cover from actual experience. You can reach out to me at john@pyracantha.co.uk

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