Control temps with bottom vent or top? Why?

[dpilot83]

I guess the entire question is in the subject.

At some point I got it in my head that airflow should be controlled with the bottom vent and the top should always be open.

Now I don’t know what to think. Really the airflow is the same either way. It’s just a question of whether you slow airflow by increasing internal pressure (closing the top vent) vs decreasing internal pressure (closing the bottom vent)

I would think closing the top vent might make things smokier?

Is one method or another more likely to produce dirty smoke rather than clean smoke?

The real reason I’m asking this is because I’m thinking of purchasing a Tip Top Temp which is an automatically opening and closing top vent. I like that there are no batteries or anything involved in it. But if adjusting via the bottom is better I might buy a Pit Bull fan and a FireBoard 2 controller instead.

[Stoneage]

FWIW here's my view.
Bottom controls air inlet, which determines how fast the fuel can combust.
Top vent controls exiting exhaust, much like a car's tail pipe. This regulates internal temperature.

I usually start the burn once the lid is on with both 100% open to get the heat at the coals by burning & venting faster for a bigger air flow. Once the temp has come up & throttle back to what I want to run & how hot/long i want to run it.
I've found that both 1/2 open is a nice grilling range around 350° or so, but I can raise it by slightly closing the top & slightly opening the bottom. To cool it I do the opposite.
The idea is they work together, not in isolation. Small movements make big differences so use I small adjustments.

When I smoke I do the snake & start with 50% on both after dropping a little pile of hot coals (the small Weber starter chimney about 1/2 full) onto the "front" of the snake. I leave the bottom there & regulate to 180~190° with the top one.
This is with Kingsford blue bag briquettes.

[JEBIV]

Personally I am not a temp control gadget guy, 95 % of the time I use the bottom vent for temp control and top vent typically wide open, I usually have a target temp range I want to cook at whatever that style cook may warrant. I have a pretty good idea where my bottom vent or vents depending on the grill need to be and start there. I am in it to have fun and eat good food, I don't want to over think it because if I overthink I might forget to fix another cocktail

[HoosierKettle]

I would learn how to get close to a temperature range using the regular vents first. I would skip the tip top temp. I’ve had one of those. I’ve never used the other atc devices mentioned so can’t speak to them.

I regulate with lower vent primarily because you run less of a risk of snuffing the coals out however I’ll still run half shut on the top if needed. I haven’t noticed any smokier food or adverse results.


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[michaelmilitello]

Similar to others, I use the bottom vents primarily.   I usually leave the top wide open and only close down if I really need to slow things down.   

Bottom= gas pedal
Top = brake pedal


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[watkinsb87]

Similar to others, I use the bottom vents primarily.   I usually leave the top wide open and only close down if I really need to slow things down.   

Bottom= gas pedal
Top = brake pedal


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I second this. The top vent is my last resort. I always try small changes in the bottom vent first.


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[Andyinlz]

Until I knew that Webers were an Internet thing and found this site, I always ran the bottom vent wide open and controlled the temp. with the top.  Unless the temp. really ran away hot (usually from too many briquettes).

Maybe 35 years or so.

I have not yet been convinced to change.

And, it is nice not to have to bend over to see the bottom one touch vent.

[Foster Dahlet]

I think this is a both/and solution, rather than an either/or solution.  I usually set bottom vent based on cook..... 1/4 to 1/2 open for low and slow, 1/2 to wide open for extended indirect, wide open for hot temps.  I then adjust the top vent to dial into my temps on low and slow, and leave top open for indirect cooks and hot cooks.  That's my way, but it doesn't have to be yours.  There is more than one way to skin a cat.

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[TXFlyGuy]

Top vent 100% open 100% of the time. You regulate the airflow and temp by using the bottom vent. The smoke (if there is any) needs to exhaust overboard quickly. If it lingers in the kettle too long, creosote will deposit on your meat. You want good airflow.

In a perfect world, both top and bottom vents would be open 100%. And you manage the fire for temp control, not the vents. That's how it works on an offset firebox smoker.

Have you ever tasted BBQ that was like eating a camp fire?

[22ket~tle]

i agree with Stonage and Foster.  its just like the big pits at the commercial places yet on a smaller scale - like JEBIV said “having fun while cooking good food” is what its all about


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[dcsham]

From my experience it's a combination of both, but for me about 75% the top vent.  When I'm smoking a rack of ribs, I always start the burn with the cover off and the bottom vent 100% open.  Once the charcoal has a good start, I put on the cover with the top vent fully open as well.  Once I hit my desired temp (about 250), I back of the bottom vent to 50% and leave them there pretty much through the entire cook.  I use the top to regulate my temperature, understanding that it's pretty common for a 25 degree variance high or low as the coals and chunks of wood burn off.  This has worked for me pretty well.

[05Train]

I use a S'nS and a TTT.  For reverse-searing steaks, I run the bottom vent at 1/2, TTT on the top.  Hold 225-230 with lots of smoke.  Key thing is to not overdo lit charcoal.  For the sear, open the bottom, remove the lid, and blast the coals with the BBQ Dragon until you've got big, open flame.

The TTT is a great way to maintain temperature, though I rarely use the Weber for longer cooks.  I find an insulated smoker holds temperature more consistently.

[TXFlyGuy]

I find an insulated smoker holds temperature more consistently.

My offset firebox smoker is made from Texas oil well pipe. At 5/8 inch thick it holds the temps pretty good. Only a bit more challenging in the winter on windy days...

This is not a set-it-and-forget-it cooker. It requires constant baby sitting to get the result you want. The Weber is less of a chore, but still requires monitoring. I use Thermoworks Smoke Alarm.

[ojay]

I generally use each equally. Meaning, half open top and bottom. From there, I adjust both in the exact same direction. If I close or open one, I do the exact same for the other. That's just the way I learned to control heat. Works for me.