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When I first started smoking meat, I thought the more smoke the better. My smoker was billowing out a thick, heavy white smoke and I thought I was killing it. After some bitter tasting meat and after surfing the internet, I found out I was doing it all wrong.
As counterintuitive as it sounds, you don’t want a thick white smoke coming from your smoker. This type of smoke is known as dirty smoke and can cause your meat to taste bitter. To get that great smoke flavor we all desire, you should aim instead for a thin blue, almost invisible, smoke also known as TBS.
In this article we will dive into the 6 most common causes of dirty smoke, how to fix them, and look at 1 pro tip to help you get that thin blue smoke.
What Is Dirty Smoke
Dirty smoke is a term used in the BBQ world to describe the thick, white smoke produced through the incomplete combustion of wood. Dirty smoke often contains lots of creosote which can leave a bitter taste on meat hence its name dirty smoke. You should avoid smoking meat in this dirty smoke.
Dirty Smoke Vs. Thin Blue Smoke
Lucky for you, it is easy to tell the difference between dirty smoke and a clean thin blue smoke. Simply look at the color of the smoke coming out of your smokestack.
Like mentioned above, dirty smoke is going to be thick, heavy, white smoke. The picture above is a great example of dirty smoke. While this may look like smoking to you, this is not the smoke we want to cook in.
Thin blue smoke (TBS) is the smoke we are after. Featured in the picture directly above, thin blue smoke is as the name describes it, thin and blue. TBS is almost invisible with a blue tint, and from a distance, it may even be hard to tell if your smoker is smoking; however, this is clean smoke and will produce the best flavor.
What Causes Dirty Smoke
In short, dirty smoke is almost always caused by the incomplete combustion of wood. This is when your fire is not receiving enough oxygen causing your wood to burn at a lower temperature. This lower temperature does not allow the wood to completely break down and react.
This incomplete combustion releases heavy white smoke and an excess of creosote leading to a more bitter flavor of meat.
Before getting into the 6 most common reasons your are getting incomplete combustion and dirty smoke, it is important to know how we achieve complete combustion. For this we turn to the process of wood combustion.
4 Stages Of Burning Wood
As you throw wood on the fire and it undergoes combustion (wood breaking down and reacting to heat) and passes through 4 stages before turning to ash.
Stage 1: Vaporization (0°- 500°)
Wood is comprised of water and during the first stage of combustion, the water inside the wood is evaporating. As you know, water and fire do not mix so in order for wood to break down and burn properly, the moisture in the wood needs to evaporate. This stage prepares the wood for combustion.
Stage 2: Primary Combustion (500° -700°)
Also known as the creosote stage, this is the first step in the breaking down of wood. Combustion is starting to take place and give off the vapors that give smoked meat its flavors; however, the fire is not burning hot enough to completely break down the wood thus releasing creosote. The beginning of this stage is where we see the dirty white smoke.
Stage 3: Complete Combustion (700° – 1000°)
Towards the end of stage two and the beginning of stage 3 is where we finally reach complete combustion. The fire is now burning hot enough to completely break down the wood. This combustion is free from creosote and produces the thin blue smoke we are looking for.
Stage 4: Char Burning: (1000° & Up)
This is the end stage of combustion before wood turns completely to ashes (think of the bed coals we roast marshmallows over). There is little to no smoke flavor being imparted into your meat during this stage.
Here is a great visual representation of this process taking place.
As you can see from the combustion process of wood, we need to make sure we are supplying our fire with enough oxygen to allow our fire to burn hot enough. Using the graph above, the sweet spot for good smoke is at the end of stage 2 and the beginning of stage 3 or about 700° (that is fire temp not smoker temp)
6 Common Reasons You Have Dirty Smoke And How To Fix It!
Now that we understand dirty smoke is the result of incomplete combustion, and we understand where complete combustion occurs, here are the 6 most common reasons you are getting incomplete combustion resulting in dirty smoke.
1) Not Enough Air Flow From Vents
Having you vents closed down to far will reduce the amount of oxygen your fire is receiving. As talked about above, if your fire isn’t getting enough oxygen, your fire can not burn at a hot enough temperature to completely break down the wood. This is the number one cause of dirty smoke.
If your dirty smoke is caused by lack of airflow, slightly open your vents to allow more air in. Doing so will increase the temperature of your fire allowing the wood to burn completely. Be careful though because if you have too much fuel, your temperature will skyrocket.
2) Too Much Fuel
Having too much fuel is another cause of dirty smoke and goes hand in hand with not enough air. When smoking meat, you want to have your smoker’s temperature set between 225° and 275° Fahrenheit. If you use too much fuel, in order to maintain those lower smoker temperatures, you really have to restrict airflow.
And while this allows you to keep your smoker temperature down, your fire is not getting enough air to burn hot enough to reach complete combustion. Getting thin blue smoke is all about finding the balance between airflow and amount of fuel.
Use less fuel. It is better to have a smaller, yet hotter fire than a larger not as hot fire. I typically use half a chimney starter worth of charcoal as my fuel source. Additionally using the minion method can help keep your fire small for longer smokes.
3) Not Letting Your Smoker Heat Up
When you first start a fire, wood has to go through the first 2 stages of combustion before getting to the good smoke, and it takes time. There is no way around it. Many people will throw their meat on the smoker before their fire has had time to pass through those first two stages.
Wait for your fire to heat up before throwing your meat on the smoker. It typically takes me 20 to 30 minutes before my smoker’s smoke turns from heavy white to thin blue smoke. Using a chimney starter, like this on amazon, can help bring your charcoal up to temperature faster.
4) Soaking Your Wood
Soaking your wood before smoking is an all-too-common practice that actually does more harm than good. I could write a whole article on why you shouldn’t soak wood, but I will try to keep It short. Like I said above, wood has to go through the first two stages of combustion before getting to complete combustion.
And what’s the first stage? Vaporization! Getting rid of all the water so the wood can burn. So why would we soak wood to add more water? That “smoke” you see when burning wood that has been soaked is steam, not smoke.
Additionally, soaking your wood is just going to delay the process of combustion as it now has to stay in the first two stages longer. Our goal is to get to complete combustion as fast as possible not delay it.
Don’t soak your wood!
5) Using The Wrong Type Of Wood
When smoking meat, you want to use hardwoods. Softwoods, such as pine have sap that produce bad smoke when burned. If you have ever gone camping in the woods, notice how smokey the fire gets when you throw pine on? Not something you want to smoke meat in.
Make sure you are using hardwoods to smoke meat. Be sure to check out my latest guide on picking the best wood for smoking meat.
6) Using Green Wood
Green wood is another term for wood that has been freshly cut. Fresh wood has a lot of water content inside which does not smoke well. Recalling early, the first stage of combustion is the vaporization of water in the wood. Fresh wood has a lot of water content and will not burn correctly.
Use seasoned wood. Wood used for smoking should have a moisture content of less than 20%. If you are buying wood from a store, you don’t have to worry as it is already seasoned. If you cut down a tree on your property, you will have to wait 6 months to a year for the wood to be properly seasoned.
Pro Tip For Getting Thin Blue Smoke
Preheat Your Wood!
If I haven’t made it clear yet, wood has to go through all the stages to get to complete combustion where we find the thin blue smoke. Our goal is to get there as fast possible. When you throw fresh wood on the fire, you can usually see dirty smoke shortly after before it clears back up.
This is normal and a direct representation of the different stages of combustion; however, we can speed this process up by preheating our wood. Instead of throwing cold wood on the fire, place your wood off to the side of your fire for it to heat up until its ready to be thrown on the fire.
This will begin the combustion process so when the wood is thrown on the fire it already has a head start and can get through the first two stages faster.