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Overnight Cook is Difficult With Vision B


American Moriyama
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Hello Guru's

 

I have just joined this board and hope there is someone that can help me. I am using a Vision Classic B from Sam's and I love it; it has exceeded my expectations for food quality. I am, however, having some trouble keeping the temperature stable during long overnight cooks. The temperature rising is not such a problem as it rises temporarily and then drifts back down. It also does not go that high as I have the intake well limited. The trouble is when the temp falls and does not recover. I can set it for 250 and it holds for a few hours, then it begins to drop. I typically adjust the intake and chimney, open the lid for a few minutes, then the temp rises and appears stable for an hour or so then begins to drop again. I have researched several things and tried to correct some of my mistakes.

 

1. Ash build up - I clean before every cook now.

2. Intake and chimney settings - I set the intake for a low temp cook and then open just a little but more to ensure enough air flow for combustion. I then control the temp with the chimney vent, it is pretty much closed at that point.

3. Charcoal grate - I removed the charcoal grate and replaced it with a Kick Ash Basket to ensure there was nothing to impede the air flow.

4. Crept up to temperature - Wanted to make sure too many coals were not lit, and they start smoldering.

5. Overshot temperature - Overshot the temperature by 50 deg and let it settle down to the correct temperature.

6. Checked for leaks - It appears that there are no leaks. The gasket seems tight and no smoke is escaping from it.

 

I have not out ruled that this grill may not be capable of stable temperature for that long. I would appreciate any insight anyone would have. I have begun to cook my butts and brisket hot and fast to make sure they are done before bedtime. The results are good, but I would prefer the overnight cooks. Thanks for your help.

 

20190622_183928_resized.jpg

20190622_184042_resized.jpg

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A bit hard to see what the setting on your top vent is...

 

How full are you loading your firebox?

 

Sounds like you have done a lot of homework. You should be able to run low and slow for hours and hours. Hopefully we can figure out what’s going on. Your cooker should definitely be capable. 

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The vent is set at a sliver. It was tough to get a good picture while trying to blow away the smoke. The opening is about the thickness of a pencil lead.

 

I filled the firebox to the top of the charcoal basket; larger pieces at the bottom, using R.O. Lit the charcoal with a Weber cube, set it in a depression on the top. I experimented with it for hours, starting about noon then smoked some chicken for dinner. After dinner, stabilized the grill at 250 and went to bed about 10:00. I checked the remote throughout the night and the temp started to fall a couple hours later. By 6 AM the grill was about 120. I had about 25% of the lump left. The ash tray was filled, but it did not seem completely to block air flow.    

 

I cleaned the grill, loaded the basket started again at 8 AM to get a stable temp. I find the temp is either falling too low or rising too high. I stabilized at 240 @ 4:00 PM. Now at 10:30 PM it has risen to 300. I suspect that the fire will not snuff out; it usually runs OK over 300. 

 

Do you think that the void between the housing and the firebox is affecting the stability? 

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Thanks for the suggestion SmallBBQr, I'll try anything. 

 

After my test on Sunday, the grill was cold by morning... I don't understand.

 

This is how I found the grill after it cooled off.

 

Top vent

 20190625_175304_resized_1.thumb.jpg.4fc9c98fcfa113c930fd7713ee6e8640.jpg

 

Lower Vent

20190625_175320_resized_1.thumb.jpg.6ad75938288f8e35e36f631781be43a7.jpg

 

Remaining charcoal

20190625_175340_resized_1.thumb.jpg.1ada0f689c77f53fc5f5d525ca77bc23.jpg

 

Ash remaining after shaking basket.

20190625_175533_resized_1.thumb.jpg.0e0dbc658af1a7843981d8cf4cd5ecd5.jpg

 

 

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I don't have any pictures, but in general if I want to hold a set temperature, I open the top vent almost completely, but close the bottom vent about the size of a 3/16" to 1/4" inch drill bit....just a tiny hole.

 

Note..when the top vent is open 100% on a Keg, it is NOT the same volume anywhere near the BGE or KJ wide open.  The cast iron top is only a series of smaller vent holes.

 

In general terms, I think the kamado needs to set up a vacuum type of airflow from bottom to top, and if the top vent is very tiny, you don't get the vacuum needed to draw in from the bottom, regardless of how large it is.

 

That said, that is just the way my Keg seems to work...

 

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A BBQ controller, though expensive, will eliminate this problem. I was only able to completely successfully get a Boston Butt done properly after buying a Stoker II. 

 

If you are feeling adventitious you could get the HeaterMeter, which is an open source BBQ controller. It is less than 1/2 the cost of a CyberQ or a Stoker II. 

 

https://www.raspberrypi.org/blog/heatermeter-open-source-barbecue-controller/

 

If the above is out of your budget, then I would suggest loading the thing up with charcoal, opening the top vent fully and giving only one set of holes for the bottom vent. 

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Hey American,

 

So I have the same grill as you but only a couple of years older. I have had the same issue and have the same setup. What I have found is really is dependent on the type of charcoal. I cooked 4 butts over the last 2 months and 3 of the 4 were perfect. I cleaned out the firebox and filled the basket, lit the coals and let it heat up for about an hour to around 250. Added my wood chunks, deflector plate and butts. It settled in around 225, I watched it for about an hour and went to bed around 11pm. I woke up at 6am and it was still sitting at 225 with about 30% of the lump burned. My vent settings were similar. My bottom vent was closed a bit more and the top was open a bit more. So this last cook I did on Friday night, same exact setup except the charcoal was different. For the previous 3 I used the B&B Hickory Blend for the first one and the Kamado Joe Big Block for 2 and 3. This last one I bought a bag of the new Royal Oak XL. It was not in the same class as the B&B or the KJ. The KJ is always consistently really big pieces. the B&B is about the same but has smaller ones built in. The RO XL was what you would expect lump to be. It was normal size lump pieces. As I lit the fire, it settled in at around 240 for two hours and the started dropping. At about 2am, the fire had gone out. I had to babysit the fire to get it to stay at 250 so I could get through the stall and get the butt to finish. I can only surmise that the difference was the charcoal. There are ones on here that will say that it doesn't matter, but I believe for these low and slow, you really need the larger pieces so that the airflow will continue. I use RO red bags for high heat cooks all the time because of the value. But from here on out, I'll only buy the KJ big block for low and slow. 

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On 6/25/2019 at 11:36 PM, SmallBBQr said:

I don't have any pictures, but in general if I want to hold a set temperature, I open the top vent almost completely, but close the bottom vent about the size of a 3/16" to 1/4" inch drill bit....just a tiny hole.

 

In general terms, I think the kamado needs to set up a vacuum type of airflow from bottom to top, and if the top vent is very tiny, you don't get the vacuum needed to draw in from the bottom, regardless of how large it is.

 

 

On 6/26/2019 at 12:45 PM, lakorai said:

... I would suggest loading the thing up with charcoal, opening the top vent fully and giving only one set of holes for the bottom vent. 

 

Thanks for the tips. I recently ran my kamado based on your suggestions. I tuned the vents for a stronger draft, the top vent about 50% open and the bottom just cracked. I got it stable at 240 around 10pm and went to bed. During the night, the temp floated up to 300 around 2am. By 8 am, it had come back down to 200 and was falling. This was better than I had previously experienced. The fire was still lit but surrounded by ash. I am going to try this method again working with a less of a draft, hopefully this will keep the temp from rising so high. I'll let you know the results.

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On 6/26/2019 at 12:45 PM, lakorai said:

A BBQ controller, though expensive, will eliminate this problem. I was only able to completely successfully get a Boston Butt done properly after buying a Stoker II. 

 

Lakorai, I agree, a controller would easily solve this problem. I manage a line of high end industrial temperature controllers in my professional life so I can get the very best control hardware. The fun of this is to to learn the dynamics of the  kamado and control the pit without automation. Once I'm proficient in manual control, I may think about trying the temp controller.

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3 hours ago, GS1397 said:

Hey American,

 

So I have the same grill as you but only a couple of years older. I have had the same issue and have the same setup. What I have found is really is dependent on the type of charcoal. I cooked 4 butts over the last 2 months and 3 of the 4 were perfect. I cleaned out the firebox and filled the basket, lit the coals and let it heat up for about an hour to around 250. Added my wood chunks, deflector plate and butts. It settled in around 225, I watched it for about an hour and went to bed around 11pm. I woke up at 6am and it was still sitting at 225 with about 30% of the lump burned. My vent settings were similar. My bottom vent was closed a bit more and the top was open a bit more. So this last cook I did on Friday night, same exact setup except the charcoal was different. For the previous 3 I used the B&B Hickory Blend for the first one and the Kamado Joe Big Block for 2 and 3. This last one I bought a bag of the new Royal Oak XL. It was not in the same class as the B&B or the KJ. The KJ is always consistently really big pieces. the B&B is about the same but has smaller ones built in. The RO XL was what you would expect lump to be. It was normal size lump pieces. As I lit the fire, it settled in at around 240 for two hours and the started dropping. At about 2am, the fire had gone out. I had to babysit the fire to get it to stay at 250 so I could get through the stall and get the butt to finish. I can only surmise that the difference was the charcoal. There are ones on here that will say that it doesn't matter, but I believe for these low and slow, you really need the larger pieces so that the airflow will continue. I use RO red bags for high heat cooks all the time because of the value. But from here on out, I'll only buy the KJ big block for low and slow. 

 

The charcoal is an easy fix. I was of the opinion that it did not matter which charcoal I used or that big pieces would make a difference. Most of the lump I buy is the R.O from Walmart or HD. I recently purchased some European beechwood lump thinking that it may perform better; same results, but the piece sizes were no different than the R.O. I'll try the Big Block. That along with the stronger draft may give me the results I need. I'll report how this turns out. Thanks.  

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Yesterday I picked up a bag of KJ Big Block from Lowe's hoping the larger pieces would resolve my overnight cook issue. Filled the bottom of the basket with fist sized pieces of lump then placed smaller BB pieces on top. Lit the grill about 7:30 pm and had it stable at 256 a little after 10 pm. The temp was very stable, a good sign. At 2:30 am, the low limit alarm on my Smoke woke me stating I was falling below 225. At 8 AM when I went out to look, the temp was 120.  The fire was still lit under the ash. I was able to restart the fire with the hot coals. I am seriously frustrated! I tuned the vents for a strong draft, top vent 40% open, bottom vent, 3 columns of holes open.

 

I did read that when using big pieces, the space between the lump could prohibit the spread of the fire. I am going to add some smaller pieces and chips from a quick lighting brand on top and in between of the KJ BB and try again, being careful not to restrict the air flow. Hopefully this will work. Am I the only one having this kind of issue???

 

Basket loaded with large and medium lump pieces.

20190703_191202_resized.thumb.jpg.ab28b05f308a7a0c79effca1b9376535.jpg

 

Temperature stabilized.

20190703_223608_resized.thumb.jpg.00f2f7b4ea847048782d55ca5da03a14.jpg

 

Burned lump - extinguished overnight

20190704_084031_resized.thumb.jpg.58b0a950dd57eb01d679bc0c5f67017a.jpg

 

Thick, fluffy white ash on burned lump. Fire still present under some of the ash. 

20190704_084228_resized.thumb.jpg.efc2d26734aa74e684277949f092cb5c.jpg

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You're starving your fire of fuel (lump). You need to load you firebox all the way up for long cooks (or any cooks for that matter). Make a " volcano" where the center is just shy of the top edge of the firebox and light the center. HTH

 

This is just my quick advice based on the pictures you provided. Do a search for more info, there are several posts on how to load your firebox and light your fire.

 

Edited by EZ smoke
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I think your snuffing your fires. Might need to double the bottom vent opening. Also make sure you are trying to stack your charcoal to provide enough airflow. I had issues of dumping from the bag and lighting it. 

 

I take out the lumps with tongs and try to stack them like lincoln logs. 

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Hey!

I have had the same issue with my classic b. I gave up on overnight cooks and just cook at a higher temp and use foil.

 

I had a Akorn before this grill and overnight cooks were very easy when using a tip top temp.

 

I tried using the tip top temp with the vision  but that didn't work either. 

 

If you figure out something please let us know.

 

-65PP

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