Why Does Firewood Hiss?

Joseph is an HVAC technician and a hobbyist blogger. He’s been working as an HVAC technician for almost 13 years, and he started blogging just...Read more

When you cut into a log with a saw, it sometimes produces a hissing noise. This is because the wood is filled with sap, which is mostly made up of water. As the blade cuts through the log, it heats up the sap and causes it to turn into steam.

The steam escapes from the cut surface of the wood and makes a hissing noise.

Barrel Fire Wood Hissing

When you throw a log on the fire, have you ever noticed that it sometimes makes a hissing sound? Why does this happen? There are a few reasons why firewood can hiss when it hits the flames.

One reason is that the moisture in the wood is evaporating. When the water inside the wood turns to steam, it can create a hissing noise. Another reason is that the sap in the wood is boiling.

Sap is full of sugars and other flammable compounds, so when it gets heated up, it can start to boil and make a hissing sound. So, if you hear your firewood hissing, it’s just because of some harmless steam or boiling sap!

Why Does Firewood Hiss When It’S Burning

When you throw a log on the fire, it hisses and sputters as the moisture in the wood turns to steam and escapes. Firewood can contain up to 45% water content. The majority of that water is in the form of free water which is easily removed through drying or seasoning the wood.

However, even well-seasoned wood still contains some bound water molecules that are held within the cell walls of the wood fibers. When you build a hot fire, these molecules convert to steam and are forced out of the wood. That’s why your firewood hisses when it first goes on the fire.

What Causes the Hissing Noise in Burning Firewood

When you burn wood in a fireplace, you may notice a hissing noise. This is caused by the water inside the wood boiling and turning to steam. When the water turns to steam, it escapes from the wood in the form of bubbles.

These bubbles pop and make a hissing noise. The amount of water inside firewood can vary depending on the type of wood and how long it has been seasoned (dried). Seasoned firewood generally contains less than 20% moisture while green firewood can contain up to 50% moisture.

The more moisture that is present in the wood, the more likely it is to produce a hissing noise when burned. If you find that your firewood is making too much of a hissing noise, there are a few things you can do to minimize it. First, make sure that you are using well-seasoned firewood.

If your firewood is still green or damp, try drying it out further before burning it. You can do this by stacking it in a dry location for several weeks or months before using it. Another option is to soak your firewood in water for 24 hours before burning it.

This will help to release some of the water from inside the wood so that it doesn’t boil and create as many bubbles when burned. Just be sure to drain any excess water off of your wood before putting it on the fire!

How Can I Stop My Firewood from Making That Hissing Sound

If your firewood is making a hissing sound, it’s likely because there’s too much moisture in the wood. When wood burns, it releases water vapor, and if there’s too much moisture in the wood, that vapor can condense on the cold surfaces of your fireplace or stove, causing a hissing sound. The best way to stop your firewood from making a hissing sound is to make sure it’s properly seasoned before you burn it.

Seasoned wood is wood that has been cut and allowed to dry for at least six months. The drying process helps to remove some of the moisture from the wood, making it easier to burn and less likely to produce those pesky hissing sounds. To season your own firewood, simply stack the logs in a dry place – out of direct sunlight and away from any rain or snow – and let them sit for at least six months before burning.

You can speed up the seasoning process by splitting the logs into smaller pieces before stacking them, as this will help more air circulate around them and hasten the drying process.


When you first put a log on the fire, you may notice that it hisses. Why does this happen? The answer has to do with the way water vapor is released from the wood.

When the log is heated, the water inside starts to turn into vapor. This process is called evaporation. As the vapor escapes from the wood, it makes a hissing sound.

The sound is caused by the steam escaping through small cracks in the wood. You may also see some bubbles forming on the surface of the log as it heats up. So next time you hear your firewood hissing, don’t be alarmed!

It’s just nature’s way of releasing water vapor from the wood.

Joseph is an HVAC technician and a hobbyist blogger. He’s been working as an HVAC technician for almost 13 years, and he started blogging just a couple of years ago. Joseph loves to talk about HVAC devices, their uses, maintenance, installation, fixing, and different problems people face with their HVAC devices. He created Hvacbuster to share his knowledge and decade of experiences with people who don’t have any prior knowledge about these devices.

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