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Monday, March 16, 2009

Offset/Horizontal Smoker Modifications

Do you have a grill like the one above? These are commonly called Horizontal or Offset Smokers. These types of grills have some advantages over the vertical smokers in that they can be used as a large standard grill by just using the large cooking chamber to grill food over coals. So if you want a smoker that will allow you to also grill burgers and brats for 20 an Offset is the way to go. Vertical smokers have an advantage in that they hold the temp much more constant and thus make them easier to use when smoking for long periods of time.

Would you like the best of both worlds? Would you like an offset that will keep the temp more constant and even rival the consistency of the vertical smokers as well as have that large cooking area if needed? Would you like the temp on one side not be as much as 100 degrees different than the temp on the other side? Would you like the thermometer in the middle of the grill be at least somewhat accurate which is impossible when the thing is assembled out of the box due to the temperature fluctuations from left to right.

With less than $30 in materials you can do all of that. Click below to see how I did it.

The first mod I did to my grill was for the rotisserie attachment that is available for the Chargriller Smoker pro that I have and is in the picture at the top of this post. While the website does not say that the rotisserie really isn't designed for a grill with a fireside box, a couple of quick modifications solved this problem. One thing, you will need a Dremel or some other device that will grind metal. Dremels are not all that expensive and are extremely handy around the house so go get one.

The main problem with the rotisserie and the firebox is that the bracket that holds the rotisserie motor is supposed to go on the side with the firebox. With the firebox attachment there the bracket must go over to the side with the shelf. But the shelf does not leave enough room for the bracket. The shelf has three slats. Removing the slat closest to the grill makes room for the bracket. Makes the shelf a little smaller but you will survive. Here is a shot of my two slat shelf and the bracket in place:

The next problem is that the bracket props the lid up quite a bit. Doesn't allow the lid to close all the way. The handy dandy Dremel made quick work of this problem by grinding the bracket down a bit to make room for the lid to sit down completely. Make sure to wear eye gear and take all necessary precautions when grinding metal. Sparks will fly:

Here is the lid now sitting flush:

OK now on to the first modification to get the temp stabilized and evenly distribute the smoke. The problem with the firebox design is all the heat is concentrated right next to the firebox. Temp gauge on the grill might read 200, but it could be close to 250 next to the box and close to 150 on the other side. That heat cooks the meat on the right much faster than that on the left. Constant jostling of meat location will help offset that but that requires opening the lid numerous times and thus allows that great smoke to escape as well as the heat. Frequently opening the lid on the cook chamber will make cause the meat to take much longer to cook.

Time to install a baffle between the firebox and the main chamber. The baffle performs two tasks. First it shields the meat closest to the firebox from the direct heat from the fire. Aluminum is not a great conductor of heat and thus it acts as a heat sink between the fire and the meat. To do this I bought a disposable aluminum high sided pan that can be found at any grocery store. The sides are about 4 inches tall. I cut the pan essentially in half at a 45 degree angle. The angle of the cut goes along the bottom of the grill. The sides of the pan cover the hole between the firebox and the main chamber. This does not look pretty, but the inside of a BBQ rarely does if it has been used at all:

Here is a shot of the baffle from inside the firebox. You can see the small gap along the bottom which forces the fire down to the bottom of the chamber which is the second task the baffle performs:

Why is it a good idea to push the smoke down along the bottom of the chamber? Simple. Without the baffle the smoke rises out of the firebox, heads straight up and then travels the length of the chamber along the roof and exits the chimney. Everything right next to the firebox cooks faster and gets more smoke but requires constant jostling of the meat to get everything done at the same time. Two disposable aluminum cookie sheets, along with the baffle resolve this problem.

Take the two sheets and poke holes in them with a sharp. pointy knife. Here is the underside of one of my cookie sheets. As you can see the smoker gets a lot of work since the cookie sheet has a smoke ring!?!?!

Place the two cookie sheets sideways across the bottom of the chamber side by side with the edge of one being over part of the baffle:

The smoke is forced down by the baffle and under the cookie sheets. The smoke escapes from under the cookie sheets evenly throughout the chamber rather than just on the side with the firebox and along the roof. This is a pic of my first smoke after I made this mod and I was blown away by the results:

The smoke/heat baffle made the temp much more consistent throughout the chamber as well as the smoke distribution but it came with one downside. While the built in thermometer is much more accurate now that I made this modification, the temp is much lower. I was forced to start using lump charcoal to get the temp in the cooking chamber hot enough to smoke ribs for say 6 hours. And I was going through a ton of charcoal.

The firebox on this grill does not do a good job of keeping the main chamber hot. See the charcoal essentially sits in it's own ash and chokes the fire out the longer the session. I tried a couple of things that did not work or were dangerous. Finally I bought this at Lowe's:

How does one use a veggie grill basket in an offset smoker to increase the temp in the main chamber? Well this mod requires some mods to the basket before it will modify the grill. See, even without the handle (which detaches easily) the basket is too big for the firebox:

On the right it is being held up by the metal lip over the ash drawer:

And on the left side the other end of the basket is being propped up inside the cooking chamber:

So out comes the Dremel again:

In a matter of a couple of minutes, the wire metal arc is no longer attached to the basket:

And a few more minutes later the metal wire arc on the other side is gone too:

Now I have a metal basket but I need to elevate it off the bottom of the chamber to eliminate the problem with ash build up squelching the heat of the fire. Four 1.25 inch screws, some hex nuts and some washers solves that problem:

Place the screws, washers and nuts at the four corners of the basket near the bottom and now the grill basket is suspended over the ash drawer:

Here is a shot of from where the ash drawer would normally be showing how much space I now have between the bottom of the basket and the firebox. The coals will now be safely elevated above the ash:

If the ash does build up and gets close to the bottom of the basket with this grill I can simply slide out the ash drawer, dump the ashes, and reinsert the ash drawer.

Now one final mod. In order to keep the smoke from escaping out of the chimney too quickly I have extended the bottom of the chimney down to close to the top of the grill grates/cooking surface. This way the smoke cannot simply rise up and evacuate the chamber. The smoke needs to come back down to find the exit through the chimney and consequently pass over the meat a second time. With this model all I needed was a three inch diameter flexible aluminum duct that cost all of about $8:

Since the bottom of the chimney is nearly exactly 3 inches I broke out the Dremel yet again (See how handy this thing is) and cut a slit straight down at the top of the duct in order to get the duct around the chimney base:

Then I attached the end with the slit around the base of the chimney at the roof of my cooking chamber:

I stretched and bent the piece of duct around the raised shelf in the back of the cooking chamber on this model and cut off the the rest of the duct leaving the bottom just about an inch above the top of the grill grates:

Here is the grill lid being propped open by the Dremel to get a shot of how close the chimney comes to the top of the grill grates when the lid closed:

Next up: Covering the holes created for the rotiserrie with some sort of flange to seal them when not using the rotisserie:

Also, I may look at going reverse flow and actually moving the chimney to the side closest to the firebox and forcing the smoke to travel the length of the chamber along the bottom and then up and back across the meat. But that is an entirely different animal as it requires a cutting torch and some welding skills two things I do not have. That is for another post if my $30 mods are not enough.


  1. Hi!
    This is mac24312 from the LCF site.. ;] I am getting this smoker grill in a couple of weeks and I am going to do what you did with the basket and the chimney. ;] I dont really want the rotisserie so what did you do to cover them holes up?


  2. You have to poke out the holes to put the rotisserie in. So you will have no problem. Good luck and keep us posted!?!

  3. Oh I will..I cannot wait to get mine and do the mods on it... ;]


  4. i did some of the mods and they work very well