Why Are My Gas Logs Turning Black?

You may probably be wondering why your gas fireplace logs are turning black after some time. You may also be wondering whether or when you should replace your gas fireplace logs.

The gas fireplace logs turn black because of the soot that accumulates on them after a while. The soot usually comes from the poor combustion process of the fuel that you use on your gas logs. The good news is that you can conveniently clean the soot from your gas fireplace logs and even prevent the soot from forming after.

Is it Normal for Gas Logs to Blacken?

It is perfectly normal for gas logs to blacken after working for some time. The gas logs blacken because of the soot that accumulates on them after some time. The soot comes from the impact of the yellow flames of your gas fireplace on the rough surface of the gas logs.

What Causes Black Soot from the Propane Fireplace?

The black soot on your propane fireplace comes from fuel molecules that fail to burn appropriately during the combustion process. Poor combustion occurs when the mixture of air and propane fuel is not perfect. Thus, the unburnt molecules accumulate on the surface of your fireplace as black soot.

Do Gas Fireplace Logs need to be Replaced?

It would be best if you replaced your gas fireplace logs as soon as their color begins to fade. The fading of the color may occur after about three years. Ceramic gas fireplace logs are usually highly durable and can take a long time before the color begins to fade.

What are the Dangers of Gas Logs Turning Black?

One of the dangers of the gas logs turning black is that the burner ports may be clogged. The burner ports are small apertures that allow your gas fireplace to generate a flame. If the logs turn black, it means that there is a lot of soot that is accumulating inside the fireplace. The soot may clog the ports and prevent the fireplace from generating a flame.

Another risk of the logs turning black relates to the aesthetic value of the gas fireplace logs. Blackened gas fireplace logs interfere with the look of the flame on your gas fireplace. In addition, the logs lose their visual appeal when they are covered with a layer of soot.

Reasons Why your Gas Logs are Turning Black

Your gas logs are turning black because of the accumulation of soot. The soot may accumulate either on the surface or inside the small cracks on your gas logs. The soot arises from the inefficient burning of the gas fuel on your fireplace.

This may result from the burner ports clogged with dirt or even small amounts of soot. In other cases, the soot in your gas fireplace may arise from how the gas logs are arranged.

If the gas logs are not properly arranged, the flame may not burn as it is supposed to. In addition, obstruction of the flame and airflow in your gas fireplace may lead to soot production.

Why you have Gas Fireplace with Black Soot on the Mantle

The leading cause of black soot on the mantle of your gas fireplace is poorly arranged logs. You need to arrange the logs properly for the flame to burn appropriately and prevent soot accumulation.

Unfortunately, it is common to fail to arrange the logs properly after cleaning them. It is always good to consult the manufacturer’s instructions when rearranging the logs inside the gas fireplace.

Inappropriate arrangement of the logs obstructs airflow inside the gas fireplace. The obstructions result in incomplete combustion of the gas fuel that burns inside your fireplace. This process leads to soot buildup in the fireplace, especially on the mantle.

Why you have Gas Fireplace Soot on Walls

Soot occurs on the walls of your house as an effect of the flames. If the gas fuel combustion is not complete, the unburnt carbon particles are emitted in the form of soot. The small soot particles rise with the warm air from the fireplace’s flames.

The soot may then be deposited on the sides of the fireplace and other places in the room, including the ceiling, the mantle, and the walls. A good percentage of the soot is deposited on the surface of the logs.

The deposition of soot on the surface of the logs gives them a black look. The soot deposited on the sides of the fireplace also makes them blacken. You can remove the soot from the sides of the fireplace by cleaning it using either a damp cloth or a brush.

Why you have Soot on the Ceiling from Gas Fireplace

You can have soot from your gas fireplace on your ceiling if it rises with the warm air and settles on the surface. Soot from your gas fireplace rises with the warm air from the heating device. If there is a large amount of soot from the fireplace, it will be deposited on the ceiling.

The soot deposition on the ceiling will become evident when the color of the ceiling begins to change. You can remove the soot from your ceiling by cleaning it using a brush or a dry rug.

How do you Fix Black Soot on a Gas Fireplace?

You can fix black soot on a gas fireplace by restoring the air-fuel ratio. Any good technician can help you achieve this by carefully cleaning out the air intake shutters. Cleaning the shutters helps to deal with the soot that accumulates on your gas logs after a while and gives them the black color.

How to Stop Soot

The most effective way of stopping the soot from your gas fireplace is to have a technician check and fix the air intake shutters. When these small components of your gas fireplace are not functioning correctly, the gas fireplace ends up emitting lots of soot.

A technician can clean these shutters to ensure enough air gets through your gas fireplace. Having enough air going through your gas fireplace is essential for maintaining the air to fuel ratio. When this ratio is ideal, the gas burns neatly without producing soot.

How to Clean Soot from Gas Logs

One benefit of having a gas fireplace is cleaning it fast and efficiently. Here is a simple procedure that you can use to clean the soot from the gas logs of your fireplace.

Switch off your gas fireplace

This should be the first step of cleaning the soot off your gas fireplace logs. Ensure that you turn off the gas fireplace before cleaning it. Remember to let the gas fireplace cool off entirely before you open it. The gas fireplace may take several minutes to cool off completely.

Remove the logs from the fireplace

The next step of the cleaning process is to remove the logs from the fireplace. Lay the logs on an old piece of cloth or newspaper. Remember to remove the logs very carefully from the fireplace.

Remove the soot from the surface and cracks of the logs

You can use either simple nylon or a vacuum cleaner to remove the soot from the surface of the logs. A brush is ideal because its bristles can access the soot that usually hides in the small cracks found on your logs’ surface.

Therefore, you do not have to dip your brush in water when cleaning the soot off the surface of the gas fireplace logs. In addition, you do not need to use chemicals when cleaning the logs. Using harsh chemicals can easily discolor your gas fireplace logs.

Return the logs inside the gas fireplace

Once you have cleaned the surface with either a brush, a damp cloth, or a vacuum cleaner, return them to the fireplace. You can refer to the manufacturer’s instructions when relaying the gas fireplace logs inside the fireplace.

You may also clean the inside of your fireplace if it is necessary. You can do this by using the vacuum cleaner to remove all the dirt that may have accumulated on the inside surface of your gas fireplace.


It is usual for soot to accumulate on the surfaces of your gas fireplace logs. Your gas fireplace produces a lot of soot when the air to fuel ratio is not attained. In addition, the soot may arise from poor airflow because of the inappropriate arrangement of the gas logs.

The good news is that you can clean the soot from your gas fireplace logs quickly. There is no need to use a lot of water to clean the soot off your gas fireplace logs. A simple brush or a damp cloth is enough for cleaning the soot.

Alternatively, you can vacuum-clean your logs to remove all the tiny soot particles that may be embedded in the cracks found on the surface of your gas fireplace logs.