Akorn Charcoal Management

Hi - I'm pretty new to the community, but I've learned a lot by reading here before I joined. Thanks so much to all for sharing what you do, it really helped out a n00b like me.

In that spirit, I'll share some failures and a success that might help other Akorn (or other kamado?) users. Check out my cook from last night:

https://www.dropbox.com/s/fe6arq2209s8148/AkornHM1.JPG?dl=0 (not sure how to inline an image... the button above didn't work)

It was a brisket, and I knew it'd take 12-16 hrs, so I was excited to get my HeaterMeter to run the Akorn smoker over night. I'd had a few successful, shorter cooks with the HM, so I figured this was cake.

Well, as the graph shows, it was not - at first. My temp control was all over the place, and eventually I snuffed the whole thing out. I figured it had to be an airflow problem, so I googled around like crazy, and found people talking about how much lump they use for a cook. I'd learned that the Akorn uses very little fuel during my earlier cooks, so I'd worked my way through a bag of lump very slowly up to this point. I had another bag of lump ready to go for this big cook, so I dumped what was left of the old bag into the Akorn, and added a bit of new stuff from the new bag. Then I set a small fire in the middle, fired up the HM, and sat back. That led to the drama you see on the left of the graph.

Eventually I read about people leaving a portion of the bottom grate of the Akorn completely free of lump to help with airflow. So pulled the meat, grill, stone, and started shifting lump around til I thought I saw the problem. When I dumped the original bag of lump into the kamado, it was primarily smaller pieces. These filtered down and basically blocked all of the gaps in the bottom grate, killing airflow. So, I carved out a wedge of space with no lump (maybe a 15 degree pie wedge of free space), restarted the fire, plonked the stone, grill, and meat back down and wondered at the lovely (mostly) straight line for the rest of the night. Well, I actually went to bed, but I did wake up a few times to check the temp (and see if my deck was on fire).

What an awesome device! I was able to sleep, then wake to a huge chunk of brisket that I could bring in to a mid-week potluck at work. It's one of the main reasons I got the kit, and I'm a very happy customer.

Some other thoughts:

I've read about dampers, but so far I've just rubber banded my fan to the bottom air vent handle/tab and closed the vent down so just the blower part of the fan sticks in. This seems to work great. The top vent is just the dimples, or a little less. Saw this idea here: https://www.kamadoguru.com/topic/5842-heatermeter-on-akorn/

I've done a number of pork shoulders since getting the HM, and it's really neat to see the "stall" in the meat probe temp line. I see no stall in the brisket line above though! It looks like a pretty straight climb. Wonder why.

Thanks again for all the help here!
D

Looking at your cook, the the HM didn't really do a whole lot. Notice your fan was barely on from about 9pm onward. For the most part, you were benefiting from the thermal capabilities of the cooker rather than the HM.

You should being seeing something like this:

Very interesting! Now yer making me want to do a nonHM test...

I think kamados benefit more from a damper control than a fan. That's how I run mine, and let the servo damper do most of the work, and have the fan cut on only at the beginning to get it up to temp, and when it might need a boost.

There are a few different fan/damper designs here, just check out the "sticky" threads (top of forum). They include the Adapt-a-Damper, the MicroDamper, the RotoDamper (RD3), the Barrel Servo, and the Offset Damper.

Thanks! Which do you use?

I currently use the Adapt-a-Damper, but have used the MicroDamper and Barrel Servo designs in the past. All have proven to work equally well.

Thanks!

Is there a good article/posting that explains a fan vs a damper? I get that the fan blows air actively, and I've got that working. I'm inferring that the damper doesn't use a fan, it adjusts the bottom vent, natural (non-fan blown?) air flow, right? It seems like every damper design I see includes a fan - but maybe that's just to push the kamado up to initial temp?

Most of the dampers include a fan so that it can stoke the fire with force fed air. I've always run in damper+fan mode on my Kamado Joe and it works really well.

I'm using this damper.

When we say "damper" we almost always mean "fan+damper". Any +damper design has the advantage that you don't need to seal up your smoker to be airtight to get good control because the damper portion can shut down the intake and somewhat nullify any natural leakage. The fan is there for startup and because the holes in the dampers are usually small so fully opening them may not allow enough airflow to maintain temperature.

The HeaterMeter can also be configured to open the damper 0%-100% before engaging the fan instead of the fan turning on at 1% output which is great because forced air can burn more charcoal due to the heat being pushed out so it allows you to only use the fan when the damper hole isn't sufficient to maintain temperature.

EDIT: Doh, beaten!

Ditto. I assumed you understood Fan+Damper. Sorry for the confusion.

I run my Akorn with the fan off until the servo is open at 50%, as once it stabilizes, it typically runs at damper open only at about 45-50% with no fan required. This, of course, is at a pit temp setting in the 230F range.

Here's an example showing stabilization at about 50%. Note that this isn't fan speed, but the percent the damper is open. The fan will not come on until the damper is past 50% open, giving it some additional air if needed, so this cook was controlled primarily with the damper portion, and very little fan activity.

Bryan Mayland said:

The HeaterMeter can also be configured to open the damper 0%-100% before engaging the fan instead of the fan turning on at 1% output which is great because forced air can burn more charcoal due to the heat being pushed out so it allows you to only use the fan when the damper hole isn't sufficient to maintain temperature.

Click to expand...

How does one actually do this open damper x% before engaging fan configuration? I've read, searched, and played around enough to guess that it's the "Fan output/on above" parameter?

First cook today. Learned a lot and lots to learn.

Yes, fan "on above _%" is how you delay the fan from coming on. If you put "on above 30%", for instance, the fan will start blowing after the HM output has passed 30%.

Yup, and also the servo's "Fully open at" parameter. If you want them to be sequential (damper fully opens, then fan turns on) you'd set them both the the same number.

Thanks guys for confirming my theory.

So I assume that the "Output" I see on the LinkMeter Home Page is actually the damper open percentage rather than the fan? Though you could configure the damper/fan combo to be the same (linear) if so desired.

I experimented a lot and finally had a 'Eureka!' moment when I realized that with a damper/fan combo, at least with the one I have, the graph is showing the damper as I had the fan turned completely off.

Nope. The output is just the output. It doesn't know or care if you've got the fan or servo damper running.

Yeah the bar shows the PID output, and there is a second background bar that shows the blower output. The damper open percentage isn't represented at all but that will be resolved during the future UI redo.

Steve_M said:

Looking at your cook, the the HM didn't really do a whole lot. Notice your fan was barely on from about 9pm onward. For the most part, you were benefiting from the thermal capabilities of the cooker rather than the HM.

You should being seeing something like this:

Click to expand...

Steve.....how did you get your Akorn to require so much output from the damper at only 230 degs F...? I typically can't get my MicroDamper to open up if I run under 250 degs F. When I was running at 275 degs F, then the output would be at about 30% which is 30% damper and no fan. When I try to run below 230, I usually have 0% output and get close to snuffing it out. Could this be because of leaks...? I just read where someone was talking about leaving an air gap spacing where the charcoal goes to allow air to flow up through...I know I haven't done that....I just fill the bottom with charcoal and light with one alcohol soaked cotton ball. You can see from my graph below that I upped the setpoint around point 69 on the graph to 275 and then I started to control better.

Any advice....? Thoughs....? Scraps...? LoL....

I'm using the offset rotary damper, which doesn't have a very large opening to begin with, and at 30% output through the damper, there's still not a whole lot of air coming out.

You can try setting your fan max % to 50% and see if that helps.

Also, I'm using a Kamado Joe, not an Akorn, but I don't think it will make much of a difference in this scenario.

Kamado Joe and Akorn are like apples and oranges. Akorn's leak, everywhere...

The intake vent can leak, the ash pan gasket can leak, behind the handles on the ash pan there's a sharp bend that tends to crack and leak, the sharp bend on the body and particularly the ash pan around the outer edge can crack and leak, it can leak between the inner and outer shells, the lid gasket can leak. If you do high heat cooking (pizzas etc) the oven type gasket on the lid can get stiff and when you close the lid it will bow out away from the lid between the pins that hold it in place. I just happened to look across at grill level one day when light was just right and saw slits of light between my lid and gasket all the way around, that one got me by surprise. I put thick nomex gasket on the top and bottom an eliminated the original gasket.

Hopefully that laundry list gives you ideas of where to look.

The easiest thing to do is set the HM to blow at 100% and build a big smokey fire, then close down the lid and all the vents and see where the smoke is blowing out, there are your leaks.

Ralph, I think you got a "bum" Akorn.

Mine had a few spots that leaked around the ash pan, and I lifted up the screws and re-tightened, and all is good.

I get 1-4 degree accuracy with 18+ hour cooks (at smoking temperatures) with these settings.

P: 2
I: .0035
D: 6

Fan on above 50%, min at 5%, max at 30%, Startup at 70%

Servo fully open at 100%

Fan/Damper is the Adapt-a-Damper

Of course, these are settings for smoking "200-300". I never saw any real reason to use a Kamado for cooking pizza, or doing any other high heat cooks. Pizzas cook fast enough, so I really never saw any reason to use the HM for it.

I've cooked chickens on my Akorn at 350, and held VERY steady with no more than 2 degrees deviation over a cook. Any temp over that, and I'll just pull out my kettle to do some "grillin'"

Fire is lit with 1 alcohol soaked cotton swab, or sometimes 1/2 of a weber cube.

Once the swab (or cube) goes out, I let the HM take over with the top damper fully open until the temp reaches 140 then choke the top damper down to a sliver past the "holes" (about an 1/8th inch on the straight section just above the holes).