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Temperature Control Problems: Too Hot, Too Cool

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Ask a Weber Smokey Mountain Cooker owner what they like most about their smoker and they’ll say, “Why, the delicious barbecue, of course!” If you press them further, they’ll say something about the ease of maintaining and controlling the cooker temperature.

Still, temperature control is one area that can be tricky for new WSM owners. Sometimes a Weber smoker runs too hot…even with all the bottom vents closed, the temperature won’t come down into the 225-250°F range. Other times, even with a full charcoal chamber and all the bottom vents wide open, a Weber smoker runs too cool…temperature won’t rise above 200°F!

Well, don’t despair! With these tips from experienced WSM users and a little practice, you’ll have your Weber Bullet’s temperature on “cruise control” in no time. But remember, don’t get too hung-up on exact temperature measurements. You can make great barbecue across a wide range of temperatures. Don’t sweat being high or low 5-10°F, even 15°F—anything in the 225-275°F range is OK for backyard barbecue.

Too Hot iconWSM Runs Too Hot

Here are some of the reasons why the Weber Smokey Mountain Cooker runs too hot, or appears to run too hot:

Shiny New Interior

Years ago, Weber used to say that the WSM may run up to 50°F hotter when brand new, due to the shiny interior surface reflecting heat back into the cooker. After a few cooks, a layer of smoke and grease would “season” the interior, making it less reflective and causing it to absorb more heat and radiate it out of the cooker, resulting in lower cooker temperatures.

Weber no longer makes this “50°F hotter” claim, and many people say they don’t notice such an effect in their new WSM. Don’t be overly concerned about this during your first few cooking sessions. If you experience high temps during your first couple of cooks, be patient and wait until you’ve got a nice coating of smoke and grease on the interior surfaces before proceeding to other remedies.

Besides, 50°F is just not that big a deal when it comes to backyard barbecue. If your new Weber Bullet is running 275°F instead of 225°F, you’re still operating at a good barbecuing temperature. Anything in the range of 225-275°F, or even as high as 300°F, is fine, especially during the first 2-3 runs with your new cooker.

Weather Affects Temperature

Take the weather into account when determining how much charcoal to use, how and when to adjust the bottom vents, and where to physically locate the cooker.

The WSM runs hotter on warm, calm days than on cold, windy ones. It also runs hotter when placed in the direct sun versus in the shade. Did you know that on a warm day, a WSM sitting in the sun with no burning charcoal can register 120°F or higher? That’s halfway to a target temperature of 225-250°F. Moving the cooker to a shady location, putting up a patio umbrella, or closing the bottom vents more than usual may be necessary to bring down the cooker temperature on a hot day.

Bottom Vent Orientation In Windy Conditions Affects Temperature

Wind can blow through the bottom vents into the charcoal bowl and stoke the fire. This problem can be solved by moving the cooker to a sheltered location, installing a wind break, or closing the upwind vent(s) and managing the fire using the downwind vent(s). See Cooking In The Wind, Rain & Cold for more information about cooking in windy conditions.

Cooker Temp Rises Naturally As Meat Cooks

During the early stages of cooking, the meat is relatively cool and absorbs a lot of heat energy. After it’s cooked for several hours, the meat does not absorb as much energy and the cooker temperature begins to creep up as a result. Therefore, some increase in cooker temperature during a cooking session is normal. However, if the temperature runs up well beyond the 225-250°F range, there may be too much fuel burning for the amount of food in the cooker.

Some Temperature Spikes Are Normal

The breakdown of charcoal briquettes while burning can play a part in sudden temperature spikes. As ash builds up and then falls away from the briquettes, new material for combustion is exposed and the temperature rises, sometimes rapidly. Also, smoke wood chunks may catch fire when the cooker is opened, due to the introduction of air into the cooker. These are normal conditions that cannot be controlled, but such spikes will usually subside within 15-30 minutes.

Keep Water Pan Full

It’s difficult to run the WSM over 275°F with a full water pan, even with all the vents wide open. The water absorbs a lot of heat energy and helps moderate the temperature of the cooker. Keep the water pan full, checking and refilling every 3-4 hours. Use cool water instead of hot if the cooker is overheating.

If you’re using an empty water pan, you need to watch the cooker temp carefully and proactively adjust vents to achieve your target temp. Start closing down the vents before the temp gets too high to control easily.

Check Thermometer Accuracy And Placement

It’s important to check the accuracy of your thermometer occasionally. Mechanical models can become inaccurate after being dropped, or sometimes an electronic thermometer’s probe just goes bad and must be replaced.

See Testing Thermometers For Accuracy for information on how to test thermometers and tips on what to do if yours is inaccurate.

If using a probe thermometer to measure temperature on the cooking grate itself, keep the probe away from the edge of the grate, especially the bottom grate. The edges are much hotter than other parts of the cooker, due to heat rising around the water pan.

Check For Air Infiltration

Tight-fitting parts make the WSM fairly airtight, which allows you to easily control combustion and thus temperature using the air vents. When you can’t seem to get the temperature down, even with all the bottom vents closed, air infiltration is often the culprit.

The two most common causes of air infiltration are a poor fitting access door and an “out of round” condition between the middle cooking section and the charcoal bowl. A detailed description of these two problems and the steps you can take to remedy them can be found on the Parts Troubleshooting page. For extremely leaky cookers, you may want to consider using a gasket kit to make your WSM more airtight.

Don’t worry about a little bit of smoke puffing out from around the access door or the edge of the lid. This is normal, especially when the unit is new, and will go away once you get a good layer of smoke and grease built up on the inside of the unit.

Difference Between Temperature At Lid Versus Cooking Surface

As discussed in greater detail on the Measuring Temperature In The Weber Bullet page, during certain portions of a cooking session the lid temperature may average 12-15°F higher than the top cooking grate temperature. So relying on lid temp may give the impression that cooker is running too hot. However, there can be times during a cooking session the temps flip-flop and the lid temp is lower than the top grate temp. Just remember that as a general rule, heat rises and the lid temp will tend to be somewhat higher than the actual grate temp…except when it’s not.

Reduce Amount Of Fuel Used Or Increase Amount Of Meat Cooked

Most folks can use the methods outlined on the Firing Up Your Weber Bullet page to achieve good temperature control. If you’ve considered all the items listed above and are still having problems, perhaps you’re using too much fuel for the amount and type of meat being cooked. Firing up 10 pounds of charcoal to cook 1 chicken or 1 slab of ribs is overkill and will make temperature control difficult—you’ve got too much heat, not enough meat.

Try to determine just the right amount of fuel that will allow you to cook a given quantity of meat for the desired time and temperature, with some heat left over for good measure. This comes with experience, so make sure to use a cooking log to track fuel usage from one cooking session to the next.

For example, 1-1/2 to 2 Weber chimney starters of hot Kingsford Charcoal Briquets is enough to cook four whole chickens or eight slabs of baby back ribs for up to 5 hours at 225-250°F.

Change Type Of Fuel Used

Remember that some charcoal varieties and brands burn much hotter than others. Lump charcoal tends to burn hotter and faster than briquettes. Try a new charcoal product and see if that makes a difference.

Stop Peeking

Every time you open the cooker to gaze upon your barbecue masterpiece, you let in air that whips the coals into a frenzy. Open the cooker only when it’s necessary to service the meat, fuel, smoke wood, and water.

Combinations Of Factors

Keep in mind that a temperature problem may be caused by a combination of the factors listed above. For example, a run-up in temperature late in a cooking session might be the result of 1) the cooker is now in full sun, no longer shaded by your house; and 2) the natural increase in cooker temperature that occurs as the meat takes on less heat energy. Look for combinations of factors that may be explain what’s happening to the cooker.

If All Else Fails

If the bottom vents are fully closed and the temperature still won’t come under control, close the top vent 50%. If even this fails, use tongs and heat-resistant gloves to remove some fuel from the cooker through the access door. If you’re feeling lucky, lift the middle cooking section off the charcoal bowl with the lid, meat, and water pan intact to access the fuel. This can be dangerous and messy, especially if you dump the contents of your cooker on the ground or into the hot coals. Remove the cooking section at your own risk. Weber warns that you should never move a hot cooker and you should never operate it unless all parts are in place.

Under no circumstances should the coals be doused with water in an attempt to bring the temperature under control. This will coat the meat with ashes and may crack the charcoal bowl’s porcelain finish.

Too Cool iconWSM Runs Too Cool

Here are a few things to consider when you cannot get the Weber Smokey Mountain Cooker to run above 200°F:

Increase Airflow Into The Cooker

Open the three bottom vents fully to allow more air into the cooker. This increases combustion of charcoal and thus increases cooker temperature. You can also try propping open the access door to let in more air.

Check Thermometer Accuracy

As mentioned in the “Too Hot” section above, it’s possible that the thermometer may be the culprit, registering a low temperature reading. See Testing Thermometers For Accuracy for testing methods and tips on what to do if your thermometer in inaccurate.

Weather And Wind Exposure Affect Temperature

Take weather and wind conditions into account when determining how much charcoal to use, how and when to adjust the bottom vents, and where to physically locate the cooker.

The WSM will require more fuel on a cool, damp day than on a warm, sunny one. Wind, more so than cold air temps, will rob the cooker of heat. Move the cooker to a sheltered location or install a wind break, start with more hot briquettes to begin with, and open the bottom vents more than usual. See Cooking In The Wind, Rain & Cold for more information about cooking in windy conditions.

Change Amount Or Type Of Fuel Depending On Amount Of Meat Cooked

The WSM will run too cool if too little fuel is used for the amount of meat being cooked. Especially during the early stages of cooking, the meat will absorb a lot of heat energy, causing the cooker temp to drop significantly. Firing up 1 Weber chimney starter of charcoal to cook a 13-pound brisket plus two 8-pound pork butts just won’t cut it—you’ve got too much meat, not enough heat. Next time, try using more fuel.

Some people find that even with the charcoal chamber filled to overflowing, the cooker won’t hold 225-250°F for more than a couple of hours. If this is your problem, try switching to a different type or brand of fuel. Some brands of charcoal briquettes burn much hotter than others. Kingsford seems to be the brand that burns hottest, longest, and most consistently, and it’s readily available throughout the United States. If you’re using a different brand, try a bag of Kingsford Original Charcoal Briquets in the blue bag and see if this solves the problem.

Lump charcoal can sometimes present difficulties because it does not always burn long or consistently. It generally burns hotter and faster than briquettes, but may drop off in temperature after a few hours, requiring the addition of more fuel. Try switching to another brand of lump to see if it provides a better result, or compact the lump in the charcoal chamber to pack as much charcoal as possible into the cooker. Otherwise, try charcoal briquettes instead, which are manufactured to provide long, consistent heat.

Check Location Of Water Pan

I received an e-mail from a man who seemed to be doing everything right, but still couldn’t get his WSM above 200°F. After exchanging a series of messages, I determined that he was placing the water pan right on top of the charcoal chamber, effectively smothering the fire! Even celebrity chefs on television can make this mistake.

Make sure the water pan is placed in the middle cooking section on the lowest set of flanges, right beneath the bottom cooking grate.

More Thermometer & Temperature Links On TVWB

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