Pellet Grill Excessive Smoke: Fixes

Some smoke is the whole point. But when your pellet grill is billowing thick white clouds like a steam engine, something is wrong. The flavor goes from pleasant and smoky to bitter and acrid, and the neighbors start giving you looks.

I have tracked down excessive smoke issues on every brand I own. The cause is almost always one of five things, and most of them are quick fixes.

Good Smoke vs Bad Smoke

First, let me calibrate your expectations. During the first 5 to 10 minutes of startup, pellet grills produce thick white smoke. That is normal. The initial pellets are smoldering, not burning cleanly, and they produce a lot of visible smoke until the fire establishes itself.

After startup, you should see thin, almost invisible blue smoke. Some people call it "clean smoke" or "blue smoke." It has a pleasant wood fire smell. If you can barely see it, that is perfect.

Problem smoke is thick, white or gray, and has a sharp, bitter smell. It makes your eyes water if you stand in the plume. Food cooked in this smoke tastes acrid and unpleasant, with a chemical bitterness that no amount of sauce will cover. If you are seeing this more than 10 minutes into a cook, keep reading.

Dirty Fire Pot

The most common cause. A fire pot full of ash prevents pellets from burning completely. They smolder instead of combusting, producing thick smoke and creosote.

The fix is the same as it is for most pellet grill problems: vacuum the fire pot. Remove grates and the heat baffle, shop vac everything out, and make sure the igniter rod is clear and visible at the bottom of the pot. I sound like a broken record about fire pot cleaning, but it really does solve the majority of issues.

If you are doing a long cook (8+ hours), check the fire pot at the midpoint. Ash accumulates during the cook itself, and a clean fire pot at the start does not guarantee a clean fire pot six hours in. On my Pit Boss Pro 1150, I have noticed the fire pot fills faster with cheaper pellets because they produce more ash per pound.

Startup Procedure Matters

How you start the grill affects smoke production for the entire cook. Here is the correct sequence:

• Open the lid. Always start with the lid open. This prevents smoke and unburned gases from building up in the cooking chamber.
• Set to smoke or the lowest setting. Let the grill run on smoke or 150 to 180 degrees for 5 to 10 minutes with the lid open. You will see the initial white smoke, then it should thin out.
• Wait for the fire to establish. When the smoke thins and you can see a clean flame in the fire pot (peek through the grate opening), the fire is established.
• Close the lid and set your temperature. Now you can close up and dial in your target temp.

Skipping this process and going straight to 225 with the lid closed often results in a smoldering fire that never fully ignites. The grill dumps more and more pellets trying to reach temperature, those pellets smolder, and you get a smoke bomb instead of a cooker.

Bad or Wet Pellets

Pellet quality is the second biggest factor in smoke production. Wet pellets smolder rather than burn. High bark content pellets produce more smoke and ash. Pellets that have broken down into sawdust burn dirty.

• Swap your pellets. If you suspect pellet quality, empty the hopper completely and refill with a fresh bag of known good pellets. I have seen an immediate difference just from switching brands.
• Check moisture content. Snap a pellet. It should break cleanly with a sharp snap. If it bends or crumbles, moisture has gotten to them.
• Dust in the bag. Open a new bag and look at the bottom. Some dust is normal. A thick layer of sawdust means the pellets are low quality or have been knocked around in shipping. Pour through a colander to sift out the fines before loading your hopper.

Low Temperature Smoke Issues

Pellet grills produce more visible smoke at lower temperatures. That is by design. At 180 degrees, the auger feeds pellets slowly, and they burn in a smoldering state that generates more smoke compounds. At 350 degrees, pellets burn hot and clean with minimal visible smoke.

If you are smoking at 180 to 200 degrees and seeing more smoke than you want, you have a few options:

• Bump the temperature up. Try smoking at 225 instead of 180. You still get plenty of smoke flavor, but the fire burns cleaner. Many competition pitmasters cook at 250 to 275 because the cleaner combustion actually produces better tasting smoke.
• Accept some extra smoke at low temps. A certain amount of visible smoke at 180 degrees is just how pellet grills work. If the smoke is bluish and smells pleasant, it is fine. Only worry if it is thick, white, and bitter.

Blocked Airflow

Fire needs oxygen. When airflow through the grill is restricted, combustion is incomplete and smoke increases.

• Check the chimney. The chimney cap should be fully open during cooking. A closed or partially closed chimney traps smoke and starves the fire of draft. Some people close the chimney thinking it traps more smoke flavor inside. It does not work that way. It just creates dirty combustion.
• Listen for the fan. The induction fan should be running whenever the grill is on. If it is quiet, the fan may have failed. Without the fan pushing air into the fire pot, pellets smolder instead of burning.
• Clean the fan intake. Ash and grease can clog the fan intake, reducing airflow even when the fan is working. The intake is usually on the back or bottom of the grill housing near the fire pot.
• Do not block the exhaust. Make sure nothing is sitting on top of the chimney or blocking the exhaust outlet. I once spent 20 minutes troubleshooting excessive smoke before realizing I had left a rag draped over the chimney from cleaning. Not my finest moment.

Grease Fires vs Excessive Smoke

Know the difference. They can look similar from the outside but require very different responses.

Excessive smoke from combustion issues produces white or gray smoke, smells like wood, and comes out of the chimney steadily. It is annoying but not dangerous.

A grease fire produces darker, oily smoke that smells like burning fat. You might see flames inside the grill (visible through the chimney or lid gaps), and the temperature on the controller will spike rapidly. An ErH error code often follows.

• If you suspect a grease fire: Close the lid. Close the chimney cap. Unplug the grill. Let the fire smother itself by cutting off oxygen. Do not open the lid. Do not spray water into the grill. Water on a grease fire makes it worse.
• Prevention: Clean the heat baffle and grease management system regularly. Line the drip tray with foil and replace it every few cooks. A clean grill does not have grease fire fuel.

Most excessive smoke issues come back to two things: a dirty fire pot and bad pellets. Keep the fire pot clean, use quality pellets stored in dry conditions, and follow the correct startup procedure. Those three habits will keep your smoke thin and blue.