Temp Control Idea/Question

[ChefJeff]

Greetings all,

Wondering if anyone has experimented with an idea that I feel like trying out. A few years ago on one of the other ceramic forums, there was a gal who kept the damper (that's the top, right ? ) completely closed for her cooks. She would regulate temperature, using just the draft opening. According to her, regulating temps in this manner is just as accurate as configuring both the draft and damper openings together. She also said that more smoke stays in the cooker this way, for great flavor.

The bottom draft openings will be very easy to experiment with concerning the amount of open-ness I would like, as it is plainly visible. The top damper at first glance, seems a little less of an exact science when opening. Lots of fun "playing" ahead for temp control, but I'd still like to know if any folks out there have successfully come up with temps when using only the bottom draft opening.

Cheers,

Jeff

[primeats]

I think with the near air tight seal with the KK, especially the Gen II model, you'll snuff out the fire before you get any heat. I have a friend who has an Egg, good cooker, but not the same caliber as the KK, AND not air tight at all. The top hat on the Egg is far from air tight, but maybe it's because he has an older model. Just my .02 worth

[Sanny]

Isn't part of the whole smoke thing the convection that draws the smoke up, past the food? So, if the top were closed, you'd get no convection. Just whatever's going on in the fire box.

Hmm.

[Majestik]

I had a friend who did something similar. He called it "dwelling". He would get the cooker up to temp and then close it all down (top AND bottom drafts) and let the food dwell in the humid radiant heat. He felt he got even more flavorful and juicier cooks that way.

I've done that on occasion, with excellent results, especially for steaks and chops, but haven't tried just keeping the top closed with the bottom draft open. Yet.

[Fetzervalve]

Let us know how it goes, no doubt it will not allow for a very high temp, likely only a couple hundred degrees at best.

It will need develop a convection current inside to stay burning, hot air rising, cooler air descending and pulling in oxygen for the burn. I'm thinking it may work wide open on the bottom, but when you start closing it down, I predict frustration.

[Syzygies]

I have a K. Looser tolerances than a KK when new, and looser still now. I also generally use a BBQGuru for low cooks. I close the damper to the point where the majority of the smoke leaves the sides rather than the top. I then use the "blue" (good stuff) masking tape to seal the more egregious side leaks. I've been meaning to fix this by forming a new gasket, but I've been busy.

That said, I don't see an either/or in this discussion, there's a continuum. Doing one's best to seal the top and sides so the only air source is the damper, makes for one extreme. Shading more in this direction is also interesting, beginners may "pull" too much with the top damper too far open.

Of late I use a variation on this for pizza. I set up a fire that naturally peaks at 700 F, then stop down the top damper part way to control it to 500 F, while the stone heats. I used to reason that my favorite pizza places in southern Italy cooked at near smelting temperatures, ergo I should cook at at least 600 F at home. Not so, the stretch from 500 F to 600 F is very sensitive for ceramic-cooked pizza. The sweet spot is where it is, different for each recipe and oven. One discovers, rather than reasons.

[DennisLinkletter]

They are both barely open

I'm all for muffling the cooker from the top.. keeps in the humidity and cuts down airflow. But that being said, you need to let some out because you need oxygen going in to feed the burn, so if something is going in something must be going out also.

So close the top until you feel the gasket touch.. Then turn the top so the thumb wings move about a half inch only.. you should just barely see smoke leaving.. In my experience if you close it down your charcoal usually dies.. It helps in your first cooks to throw in some wood for smoke so you can visually see your airflow..

[Fetzervalve]

I tested this yesterday. I had a 400 - 425 fire going and shut the top damper, I left the bottom wheel open full. I checked it about 2 hours later and the fire was out. Not a glimmer or a glow, no sign of life.

I don't know what kind of leaky cooker the gal had that suggested this method, bit it will not work on a KK.

[johnnyboy]

I tested this yesterday. I had a 400 - 425 fire going and shut the top damper, I left the bottom wheel open full. I checked it about 2 hours later and the fire was out. Not a glimmer or a glow, no sign of life.

I don't know what kind of leaky cooker the gal had that suggested this method, bit it will not work on a KK.

Can anyone explain how that happens? Just seems odd to me, why/how the fire goes out when the draft is full open. Is it because heat/smoke goes up not down, so can't get out, thus causing air blockage so to speak.

[bryan]

Could be the draft door is open but there is no draft (just a dead air space.)

Like the age old question what do you put in to a bucket of water to make it lighter?

holes

[Fetzervalve]

I'll throw out my theory.

I think if you started with a cold cooker, you would get some flow; hot air rising pulling in fresh air with the cooler air (relatively) in the dome descending. As the cooker gets hotter it will cause an ever shortening convective loop, until it stops.

It certainly tells me that a leaky draft door will not allow the fire to continue to burn unless you have a leak up top also.

[ThreeDJ16]

I tested this yesterday. I had a 400 - 425 fire going and shut the top damper, I left the bottom wheel open full. I checked it about 2 hours later and the fire was out. Not a glimmer or a glow, no sign of life.

I don't know what kind of leaky cooker the gal had that suggested this method, bit it will not work on a KK.

Can anyone explain how that happens? Just seems odd to me, why/how the fire goes out when the draft is full open. Is it because heat/smoke goes up not down, so can't get out, thus causing air blockage so to speak.

Oxygen displacement. Since the smoke cannot escape, it smoothers the fire by displacing oxygen. A fire need heat, fuel and oxygen to happen. Take out any of the three and you got no fire.

-=Jasen=-

[mguerra]

gremlin

I must have an air leak somewhere! At midnight last night I shut down the Bronze Behemoth and at noon today it's still burning. Tel-Tru is 250. The bottom doors are pushed fully to their seats and appear flush and sealed. Top damper is screwed on down tight. Bottom vent wheel is closed. The only opening I know of is the temp probe hole, which I just stuck a cork in before returning to work. Although I don't have the gas burner, the gas burner support rods are down there, I'll check to see if there is some kind of leak associated with them or their mounting. My plan is to throw in some smoke wood and then pressurize the cooker and look for smoke egress.

[bryan]

When it happened to me I had not closed the Guru slide vent.

[jdbower]

Depending on what you're burning (the KKEC stays alive for quite some time without O2) the temp probe port may be the culprit and I used aluminum foil to plug mine up. Another thing to check is that the lid is fully closed, there's two levels of latching and someone I know (who happens to have the same initials as I do, and I think he lives nearby...) sometimes forgets to fully latch the lid causing a decent amount of airflow. Beyond that your smoke idea is a good way to find it. It works even better with a power draft control (Guru/Stoker).

[mguerra]

pressurized

Got home from work and did my pressure test. But before I did that I did a very methodical visual inspection. Even with the damper top fully screwed down, there is some smoke venting out the top. The closure surface of the top appears flat and smooth to the eye, I did not lay a straightedge on it. Visually the top gasket appears intact enough. Under pressure, a little smoke comes out around the two bottom doors. I pulled them both out to be sure there was nothing impeding their closure, and closed them again. Still a little smoke under pressure. I can't imagine those doors are open more than a few thousandths at most. They feel very well apposed to their seats. Detected no smoke around the lid/base junction. Apparently a minute amount of leak is sufficient to maintain combustion. Half the fuel for this cook was extruded coconut, the other half a mix of Royal Oak lump and briquets. Every previous cook did not fail to shut down and did not contain coconut. I dunno. It's 5:30 and I shut that thing down 17 hours ago!

[Firemonkey]

I have also found that the extruded coconut takes much longer to completely extinguish. Nothing like what you describe, so it does sound like you have some sort of leak. I dont have a power draft controller, but I am assuming that you closed or plugged that port?

I have also had small amounts of ash slip into the door frames, which made them feel like they were tightly closed, even though they had a very slight leak, especially the rear door. My solution is that as soon as I have enough ash built up in the bottom of the cooker, I push it all up against the rear door to bury it. As small as that leak may be, i find that this helps in my case.

[ThreeDJ16]

If you use a power draft on the KK you will get smoke leakage, it's not going to be pressure tight, but that is not a problem. But under natural draft conditions, you should not see any other smoke other than the top damper.

Also, a very small leak over the entire edge of a draft door or lip seal has a larger area than one would think. Simply a small amount of charcoal/ash grit on the sealing surface of the draft door can be enough to keep a smolder going for a while. Especially if the top damper is not completely sealed since natural draft will increase the draw. Good practice to keep both doors sealing surface wiped down on occasion.

-=Jasen=-

[Duk]

Where the heck have you been DrunkJ ??

[ThreeDJ16]

Where the heck have you been DrunkJ ??

Still here, just have not had much time to post lately....barely even cooked out.