How to run a gravity feed??

Also called Stump's Clone.
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Smokerbuild
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How to run a gravity feed??

Post by Smokerbuild » March 25th, 2020, 9:52 am

I built the mini to the specs on the plan. I get a temperature of 40+ degrees higher on the top shelf compared to the lowest shelf next to the heat channel. Would I get a consistent temperature throughout the CC if I put a water pan on the heat channel to act as a heat sink?
Another question: any issues putting wood splits in the ash pan versus wood chunks? I don’t know if a split would be to much wood at one time in the ash pan and possibly create a large fire in the ash pan.


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Re: How to run a gravity feed??

Post by SmokinDTown » March 25th, 2020, 12:28 pm

Hi Smokerbuild,
I have used a water pan, and I think the results are better. This is my 3rd one. I built this one slightly different than Frank's plan.

Are you using the natural draft only of this smoker? Or is a fan involved? With only 10" between the upper and lower grill that 40 degrees seems like too much.

Be careful on the wood! My experience is with this type smoker, a very small amount of wood is needed. Kind of disappointing! 2 ounces. If you put a lot of wood in, the meat gets bitter.

Hope this helps.



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Re: How to run a gravity feed??

Post by Smokerbuild » March 25th, 2020, 1:20 pm

SmokinDTown wrote:Hi Smokerbuild,
I have used a water pan, and I think the results are better. This is my 3rd one. I built this one slightly different than Frank's plan.

Are you using the natural draft only of this smoker? Or is a fan involved? With only 10" between the upper and lower grill that 40 degrees seems like too much.

Be careful on the wood! My experience is with this type smoker, a very small amount of wood is needed. Kind of disappointing! 2 ounces. If you put a lot of wood in, the meat gets bitter.

Hope this helps.
I’m using a FireBoard fan. What are you referring to when you said “2 ounces”? What temperatures are you getting between the bottom and top racks?


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Re: How to run a gravity feed??

Post by SmokinDTown » March 25th, 2020, 1:36 pm

I’ll go and get some temps for you now. I’m smoking some spares.

The 2 ounces is total amount of wood. I put a piece or two in the ash box. Two small pieces of cherry.



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Re: How to run a gravity feed??

Post by SmokinDTown » March 25th, 2020, 1:44 pm

2 degrees total. 248. 250.



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Re: How to run a gravity feed??

Post by Smokerbuild » March 25th, 2020, 2:27 pm

SmokinDTown wrote:I’ll go and get some temps for you now. I’m smoking some spares.

The 2 ounces is total amount of wood. I put a piece or two in the ash box. Two small pieces of cherry.
For the entire cook you only add that much wood?
Are you using the water pan and getting those temps?


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Re: How to run a gravity feed??

Post by JKalchik » March 25th, 2020, 2:53 pm

Hrrrm.... I'd have to go back and run it again, on my double pan GF, I was getting less than that between the top & bottom racks. Never put a water pan in it, and I use a HeaterMeter.

Re: bitterness..... any chance that you're putting big chunks right in the ash box when you load food? The wood should have a chance to catch & burn down a bit, that first blast of smoke tends to be a bit acrid.


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Re: How to run a gravity feed??

Post by SmokinDTown » March 25th, 2020, 3:47 pm

Smokerbuild:

I am getting 248 and 250 between the top rack and the bottom rack. I am running a water pan. The ball valve is 3/4 open or so. I have a fan providing air to the valve.

We both agree that th 40 degree difference you have is too much, but for the life of me, I can’t come up with a good reason? We are only talking about a few inches difference in height inside the cook chamber. No chance that one sensor is off?

Yes, just a small amount of wood. Fits in my hand. Have you read Dr. Biondi’s writeup on smoke?



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Re: How to run a gravity feed??

Post by Big T » March 25th, 2020, 4:02 pm

I would agree that it sounds like an issue with one of your temp probes.


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Re: How to run a gravity feed??

Post by Smokerbuild » March 25th, 2020, 8:46 pm

SmokinDTown wrote:Smokerbuild:

I am getting 248 and 250 between the top rack and the bottom rack. I am running a water pan. The ball valve is 3/4 open or so. I have a fan providing air to the valve.

We both agree that th 40 degree difference you have is too much, but for the life of me, I can’t come up with a good reason? We are only talking about a few inches difference in height inside the cook chamber. No chance that one sensor is off?

Yes, just a small amount of wood. Fits in my hand. Have you read Dr. Biondi’s writeup on smoke?
I will do a test burn and put in a water pan. I usually open the ball valve wide open and run the fan. I’ll try closing the valve 3/4. I never thought about closing down the valve with a fan running.


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Re: How to run a gravity feed??

Post by Smokerbuild » March 25th, 2020, 8:47 pm

Big T wrote:I would agree that it sounds like an issue with one of your temp probes.
I’ll check both probes.


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Re: How to run a gravity feed??

Post by richy20 » Yesterday, 6:50 pm

Any updates on this? This also happens to me but I usually don't get the opportunity to fully load it. When I do use all the shelves I use the variance to my advantage. Thicker cuts at the bottom rack. I have noticed that when I heat it up a long time in advance I get less variance. I am going to try shutting the valve next time and checking with my maverick. I also use a fan. I use the BBQ guru digiQ. I put the pit probe underneath the middle rack and the bottom rack it is hotter by 20degrees and the top rack is about 20degrees lower. Atleast its consistent LOL.



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Re: How to run a gravity feed??

Post by Smokerbuild » Today, 9:12 am

richy20 wrote:Any updates on this? This also happens to me but I usually don't get the opportunity to fully load it. When I do use all the shelves I use the variance to my advantage. Thicker cuts at the bottom rack. I have noticed that when I heat it up a long time in advance I get less variance. I am going to try shutting the valve next time and checking with my maverick. I also use a fan. I use the BBQ guru digiQ. I put the pit probe underneath the middle rack and the bottom rack it is hotter by 20degrees and the top rack is about 20degrees lower. Atleast its consistent LOL.
I ran a test yesterday in the GF Mini. First, I checked all temperature probes by putting them in a glass of ice water. All probes, FireBoard and ThermoWorks read within 1 degree of each other. Probes were placed on three racks, bottom, middle and top. The middle and top rack ran within 10 degrees of each other. The bottom rack ran 20+ degrees hotter than the other probes. I ran with and without a water pan, as a heat sink. Ball valve wide open with the FireBoard fan. The interesting part for me was when I put both ThermoWorks probes next to the FireBoard probe that was controlling the fan. The FireBoard temp indicated 20+ degrees hotter than both ThermoWorks probes. The ThermoWorks dots both showed the same temperature.


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Re: How to run a gravity feed??

Post by richy20 » Today, 12:28 pm

Very interesting. I've been using my ugly drum a lot for these smaller cooks but once this corona virus deal is over and I use my GF I will do more testing. I will borrow my cousins maverick and use my maverick and compare with the BBQ guru and analyze the crap out of everything. I will share my findings. Stay Safe, Thank you and good luck.



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Re: How to run a gravity feed??

Post by Dirtytires » Today, 1:04 pm

Remember that smoking is just as much an art as it is science. The temp your probes read are not really as important that they be exact temp but rather relay a standard temp that you can adjust your cooking methods off. I always try to make sure all my thermometers read approx the same temp but I really dont care what that temp is as long as I can repeat it for the next cook.

Also remember that everything like sun, wind, humidity, charcoal and general attitude of the smoker will contribute to the results and temp. Many times, a 20-40 degree swing is all those conditions will allow and that is perfectly acceptable.

My point.....don’t over analyze this too much.



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