Lump burn rate with fan and charcoal brands

JTS2019

So i have a question. I recently bought a fan/fireboard unit for my bge. i also changed from royal oak to rockwood. I never ran out of lump during a long cook until my last cook using the fan and rockwood. So im wondering, does anyone know if the rockwood burns faster or if my fan unit makes the burn less efficient somehow? anybody got any observations on either?

stlcharcoal

On the temp controller, the BGE is using the same amount of BTU's to maintain 225F (or whatever it was) whether or not you are using a controller.  The only change is that the temp probe is driving the cook rather than the natural flow.  So if while you may have been dialed in on the dome temp before, now it's grate temp or wherever you have the probe.  But if the probe is bad, too near the meat, above a drip pan, etc, then you can definitely see some changes.  Clip it to the dome temp for about 10 minutes next time and see if they line up.

On charcoal, BTU/# is BTU/#.  Our average is around 11,000/#.  It cannot burn any faster without the subsequent rise in temperature.  So, if you're truly maintaining a low and slow temp, then it should just as long, if not longer than any other brand you're used to.  But if the temp you're seeing is not the actual temp, then that could change things.  Sometimes the firebox wasn't completely full because a long piece got in there sideways and there was a bunch of air space.  Did you start with brand new lump or was their some left over from last time?  Were you cooking more meat than usual, water pan, high winds, anything else different......all those of those can suck BTU's a little more than normal.

Give it another shot and see what happens.  

fishlessman

if your doing a big cook with cold meat the fan will increase the fire and chase the temps at the beginning of the cook. with just using the vents you stabilize the temps slowly, add the meat, and wait for the temps to climb slowly back up with a smaller fire. ive seen 1000 degree fires chasing temps with 30 pounds plus meat with the cooking temp under 200 and a cold dome with just using vents on really big cooks, you quickly learn you dont want to chase temps and burn up all that lump at the beginning of the cook. the fan will chase temps so just be aware of that and watch those loaded egg cooks

stlcharcoal

fishlessman said:

if your doing a big cook with cold meat the fan will increase the fire and chase the temps at the beginning of the cook. with just using the vents you stabilize the temps slowly, add the meat, and wait for the temps to climb slowly back up with a smaller fire. ive seen 1000 degree fires chasing temps with 30 pounds plus meat with the cooking temp under 200 and a cold dome with just using vents on really big cooks, you quickly learn you dont want to chase temps and burn up all that lump at the beginning of the cook. the fan will chase temps so just be aware of that and watch those loaded egg cooks

That and the cold ceramic sucking up all the heat.  If I don't stabilize it myself, I always set my Flameboss for 180F, let it sit for 30 minutes or so, then bump it to 200, then 225.  It's usually smart enough to do it on it's own, but I've had a few overshoots, so I prefer to do what you describe or step it up through the fan.

fishlessman

stlcharcoal said:

fishlessman said:

if your doing a big cook with cold meat the fan will increase the fire and chase the temps at the beginning of the cook. with just using the vents you stabilize the temps slowly, add the meat, and wait for the temps to climb slowly back up with a smaller fire. ive seen 1000 degree fires chasing temps with 30 pounds plus meat with the cooking temp under 200 and a cold dome with just using vents on really big cooks, you quickly learn you dont want to chase temps and burn up all that lump at the beginning of the cook. the fan will chase temps so just be aware of that and watch those loaded egg cooks

That and the cold ceramic sucking up all the heat.  If I don't stabilize it myself, I always set my Flameboss for 180F, let it sit for 30 minutes or so, then bump it to 200, then 225.  It's usually smart enough to do it on it's own, but I've had a few overshoots, so I prefer to do what you describe or step it up through the fan.

never used a fan device but have seen it with just the vents. its the big cooks where things can get away from you, not so much the smaller ones like a rack of ribs. you really need to be mindful at the beginning of the cook with larger cuts of meat and never trust the temp probes during that time as well

JustBuggin

Interesting. I've noticed a considerably slower charcoal usage after starting to use a Signals w/ fan. I just figured it was something to do with how I was lighting the lump before I used the fan. I would say give it a couple more cooks to see if it continues, it may have just been the size of the lump as stated above.

lousubcap

@JTS2019 - welcome aboard and enjoy the journey.  Above all, have fun.  Don't know how long you have been reading the forum but FYI @stlcharcoal knows a bit about lump charcoal.  He owns Rockwood.  Heed well his inputs.  FWIW-

Photo Egg

stlcharcoal said:

On the temp controller, the BGE is using the same amount of BTU's to maintain 225F (or whatever it was) whether or not you are using a controller.  The only change is that the temp probe is driving the cook rather than the natural flow.  So if while you may have been dialed in on the dome temp before, now it's grate temp or wherever you have the probe.  But if the probe is bad, too near the meat, above a drip pan, etc, then you can definitely see some changes.  Clip it to the dome temp for about 10 minutes next time and see if they line up.

On charcoal, BTU/# is BTU/#.  Our average is around 11,000/#.  It cannot burn any faster without the subsequent rise in temperature.  So, if you're truly maintaining a low and slow temp, then it should just as long, if not longer than any other brand you're used to.  But if the temp you're seeing is not the actual temp, then that could change things.  Sometimes the firebox wasn't completely full because a long piece got in there sideways and there was a bunch of air space.  Did you start with brand new lump or was their some left over from last time?  Were you cooking more meat than usual, water pan, high winds, anything else different......all those of those can suck BTU's a little more than normal.

Give it another shot and see what happens.  

Is there any chance that by using a fan driven controller, you are “mini stoking” the fire hundreds/thousands of times during a cook, hence burning a little more lump than a slow, even, natural draft? 

brentm

The only explanation is that the forced air is also forcing these BTUs out the chimney, to maintain an exact temperature.

Otherwise, cue the "physics" meme!

stlcharcoal

Photo Egg said:

stlcharcoal said:

On the temp controller, the BGE is using the same amount of BTU's to maintain 225F (or whatever it was) whether or not you are using a controller.  The only change is that the temp probe is driving the cook rather than the natural flow.  So if while you may have been dialed in on the dome temp before, now it's grate temp or wherever you have the probe.  But if the probe is bad, too near the meat, above a drip pan, etc, then you can definitely see some changes.  Clip it to the dome temp for about 10 minutes next time and see if they line up.

On charcoal, BTU/# is BTU/#.  Our average is around 11,000/#.  It cannot burn any faster without the subsequent rise in temperature.  So, if you're truly maintaining a low and slow temp, then it should just as long, if not longer than any other brand you're used to.  But if the temp you're seeing is not the actual temp, then that could change things.  Sometimes the firebox wasn't completely full because a long piece got in there sideways and there was a bunch of air space.  Did you start with brand new lump or was their some left over from last time?  Were you cooking more meat than usual, water pan, high winds, anything else different......all those of those can suck BTU's a little more than normal.

Give it another shot and see what happens.  

Is there any chance that by using a fan driven controller, you are “mini stoking” the fire hundreds/thousands of times during a cook, hence burning a little more lump than a slow, even, natural draft? 

Yes, but no.....because immediately after you're "mini snuffing" the fire out.  It comes down to the law of conservation of energy.  You cant get rid of those BTUs without a higher temp.  Carbon is a constant.

About the only thing you could say is that its pushing heat out of the egg because of the pressure from the fan.....but with a 7 CFM fan running at 10-20% for just a few seconds sporadically, it cant be enough to measure.  If you didnt use the controller, wind creating a flue over the chimney cap could cause the same fluctuation in usage.

brentm

even if forced air uses a little more fuel, it's not a problem.  You just add more if you need to.  I usually cover my food until the new lump burns clean.  

I usually prefer to not overfill my firebox and get air gap between the plate setter.  I'll add lump the next day if I need to.

The thermal mass of the cook is another variable.  Don't compare a 7lb pork shoulder to an 18lb brisket

StillH2OEgger

brentm said:

even if forced air uses a little more fuel, it's not a problem.  You just add more if you need to.  I usually cover my food until the new lump burns clean.  

I usually prefer to not overfill my firebox and get air gap between the plate setter.  I'll add lump the next day if I need to.

Just curious about the cons are with overfilling the firebox? It seems like the steps you're taking to add more lump are more trouble than whatever benefit it would seem to provide.

brentm

StillH2OEgger said:

Just curious about the cons are with overfilling the firebox? It seems like the steps you're taking to add more lump are more trouble than whatever benefit it would seem to provide.

You're probably right.

I swap my drip pan out nowadays too.  But the reason I don't fill it all the way up is I really try not to let the the fat/aujus smoke.  Chances are, the water-based drippings will turn to black foam, but I can keep it low enough to keep the fat clear and not get dark and smokey.

My theory is that keeping the fire sufficiently air gapped from the platesetter is it reduces my chances of letting out the bad smoke.  I also keep my drip pan off the plate setter with a spider.

stlcharcoal

If you want to keep the fat from flaring up, just dump a bunch of salt in the drip pan.

northGAcock

stlcharcoal said:

If you want to keep the fat from flaring up, just dump a bunch of salt in the drip pan.

Thank you. I learned something new. Not sure I have had the problem, but will put it into my back pocket. 

brentm

stlcharcoal said:

If you want to keep the fat from flaring up, just dump a bunch of salt in the drip pan.

Is the salt like kitty litter?  What's the science behind it?  Does it raise the boiling point of fat???

Cire69

It could be that RW has larger sized pieces, so there is more dead space between pieces, and therefore less lump to burn compared to what you were using before. 

dbCooper

OT from original post: My understanding is one wants the drip pan elevated .5 inch or so above plate setter, or whatever your heat deflector is.

The idea being you want the "drippings" to simmer in the pan, rather than vaporize, as can happen if drip pan is directly on the heat deflector.

brentm

That's not going to always give you the golden ticket.  If you're running your temperatures above 225 for hours on end, your oil is eventually going to start to smoke.  It's just like oil in a fat fryer.  Eventually it wears out, gets dark, and starts smoking.  You're not cooking food in the oil, so you can't taste the gradual change like you would in a deep fryer.  But the concept is similar.  You know when it's time to change oil.  And the oil ages pretty quickly in the bottom of the pan.  There's not much depth, but there's quite a bit of heat.

You can smell it in the vents.

I thought about water in the pan, but it's just easier to change them out after 12-16 hours.

StillH2OEgger

brentm said:

That's not going to always give you the golden ticket.  If you're running your temperatures above 225 for hours on end, your oil is eventually going to start to smoke.

I usually smoke between 250-275 and have never encountered this. Butter will smoke at 300 degrees so I can't imagine that any meat drippings into an air-gapped drip pan will produce bitter smoke at a lower temperature than that.

brentm

Looks like lard's smoke point is 370F.  https://www.seriouseats.com/2014/05/cooking-fats-101-whats-a-smoke-point-and-why-does-it-matter.html

I still maintain my position that a layer of oil cooking under your food is going to impart some flavor upon it.  It is more than zero.  And usually when I'm tearing things apart, the fat temp is higher than the pit temp (I drop my probes in it before moving the food).

I think some folks don't mind dripping fat smoke.  It's smells and tastes like BBQ to them (think flavor bars on the gasser Webers). 

It could have been another issue I didn't check for.  My buddy pulled a tar ball/clump out of a bag of Royal Oak.  It looked like it came off the side of the oven in the lump factory.  Just the smallest amount on your finger was acrid.  Like really acrid.  It'd ruin a cook for sure.  He does a good job of sorting his lump by size and inspecting it.  I stopped using Royal Oak on brisket after that.  But it could be a problem for any charcoal manuf.

XC242

brentm said:

It could have been another issue I didn't check for.  My buddy pulled a tar ball/clump out of a bag of Royal Oak.  It looked like it came off the side of the oven in the lump factory.  Just the smallest amount on your finger was acrid.  Like really acrid.  It'd ruin a cook for sure.  He does a good job of sorting his lump by size and inspecting it.  I stopped using Royal Oak on brisket after that.  But it could be a problem for any charcoal manuf.

That’s creosote.

stlcharcoal

XC242 said:

brentm said:

It could have been another issue I didn't check for.  My buddy pulled a tar ball/clump out of a bag of Royal Oak.  It looked like it came off the side of the oven in the lump factory.  Just the smallest amount on your finger was acrid.  Like really acrid.  It'd ruin a cook for sure.  He does a good job of sorting his lump by size and inspecting it.  I stopped using Royal Oak on brisket after that.  But it could be a problem for any charcoal manuf.

That’s creosote.

Or likely glob of grease from a loader bucket.....it happens.

JTS2019

stlcharcoal said:

On the temp controller, the BGE is using the same amount of BTU's to maintain 225F (or whatever it was) whether or not you are using a controller.  The only change is that the temp probe is driving the cook rather than the natural flow.  So if while you may have been dialed in on the dome temp before, now it's grate temp or wherever you have the probe.  But if the probe is bad, too near the meat, above a drip pan, etc, then you can definitely see some changes.  Clip it to the dome temp for about 10 minutes next time and see if they line up.

On charcoal, BTU/# is BTU/#.  Our average is around 11,000/#.  It cannot burn any faster without the subsequent rise in temperature.  So, if you're truly maintaining a low and slow temp, then it should just as long, if not longer than any other brand you're used to.  But if the temp you're seeing is not the actual temp, then that could change things.  Sometimes the firebox wasn't completely full because a long piece got in there sideways and there was a bunch of air space.  Did you start with brand new lump or was their some left over from last time?  Were you cooking more meat than usual, water pan, high winds, anything else different......all those of those can suck BTU's a little more than normal.

Give it another shot and see what happens.  

Having thought about it some and looking back through my notes, i think i figured it out. Combination of factors, First of all, this was by far the coldest weather ive done a long cook in for sure and your thoughts on btus set me on that path. 2nd, i think the RW does have significantly bigger pieces and hence, more air space between pieces. Lastly, this was my longest cook as i usually wrap my pork butts shortly after stall but this time i waited a while to see if i could render out a little more fat cap before wrapping. Thanks for all our thoughts. You make a great product.