I'm not sure what you're using but I've pegged the thermometer on my gas grill at 900*, so I know it gets over that. Of course, the dials on mine go to "11".
The science behind the gas vs charcoal debate
- Thread starter hominamad
- Start date
I'm not sure what you're using but I've pegged the thermometer on my gas grill at 900*, so I know it gets over that. Of course, the dials on mine go to "11".
Shagdog
Quintessential Chatty Farker
- Joined
- Jul 1, 2013
- Location
- Grayslak...
I don't use gas so I have no idea how hot they actually get. It was all purely theoretical, Mr Scientist man.
I don't even know what the question is. I do know that I should assume a spherical pit and an isotropic, homogeneous fire if I'm going to solve this thing. Can I simplify the problem by putting the fire in a vacuum? Of course if you want a real-world answer, you're just going to have to install some dials on your charcoal pit that go to 11 and see if you get a hotter fire that way. I'm betting you won't be disappointed. :thumb:
YetiDave
is one Smokin' Farker
- Joined
- Jul 23, 2013
- Location
- Manchest...
Deleted
Last edited:
YetiDave
is one Smokin' Farker
- Joined
- Jul 23, 2013
- Location
- Manchest...
I think the upper limit of both wood and gas is determined not only by the amount of available fuel, but also the amount of oxygen available to a fire and the vessel that the fire is in. If you had a large, open pit full of coal it wouldn't get nearly as hot as the same amount of fuel in say a conical vessel given the same amount of available air
In short -
Fuel amount
Oxygen available
Insulation/thermal mass
I think....
In short -
Fuel amount
Oxygen available
Insulation/thermal mass
I think....
- Joined
- Jan 3, 2014
- Location
- Detroit...
So Gore how hot does the optigrill get?
Now that is a very good question. I honestly don't know. I really should load it up with charcoal to find out, but I don't have a thermometer. :tsk:
Kathy's Smokin'
Babbling Farker
- Joined
- Aug 16, 2011
- Location
- Guelph...
I think one of the best people here to answer the volume of fuel question could be bbqbull (Mike) who is a firefighter. I think anyone who has fought a forest fire where there is unlimited fuel would have knowledge on this subject, too. Having said that, I doubt the relationship between how hot a fire that coal can create is only a direct relationship with volume, like half a chimney's worth giving X temperature and a full chimney giving twice that temperature. Like others that have chimed in, I think there is an upper limit to the temperature a material can reach based on that material's chemistry. Materials are limited by their rate of oxidation (ability to burn) in a given set of circumstances.
I've heard fires in old buildings talked about as hotter because the lumber in their structure is so dry from age. The amount of moisture in wood must be a variable in determining what temperature burning that wood can reach, too.
Gotcha. :thumb:
One of the myths as regards heat versus BTU ratings. BTU ratings measures the potential of a given amount of fuel to raise a pound of water one degree Fahrenheit. Be it gas or charcoal, or wood or alcohol, all have a given BTU rating. It means very little relative to cooker efficiency. Issues such as air flow, conduction, material thermal efficiency can all affect the way a cooker transfers heat to food.
In the end, no single fuel is better due to it's ability to create heat, as greater heat can be achieved with any fuel. Controlling heat is an issue to be sure, and to be honest, gas offers a much better means for controlling heat. Doesn't mean it's better.
In the end, no single fuel is better due to it's ability to create heat, as greater heat can be achieved with any fuel. Controlling heat is an issue to be sure, and to be honest, gas offers a much better means for controlling heat. Doesn't mean it's better.
Just my input from a lowly newbie.
If you aren't massively into BBQ and can afford a decent gasser, then it's worth it as its convenient, cleaner and generally less time for quick grills like steaks (very little waiting time). If you, however are into your BBQs then I can see the merits of coal. It's more authentic, more of a process, easier to get that smoked taste and I guess the 'proper' way of doing it.
I personally can't see the point of using coal because I don't BBQ much and when I do, although I like the process, standing in the pissing rain, trying to light the coal and waiting for the coals to settle isnt my idea of fun.
Totally understand why folk do coal and equally why those who prefer gas.
Do I think with most things it matters to the eventual outcome? Not really from experience. A decent cook will produce great food regardless of what they cook on.
What matters at the end of the day is that you cook food that people and you enjoy.
If you aren't massively into BBQ and can afford a decent gasser, then it's worth it as its convenient, cleaner and generally less time for quick grills like steaks (very little waiting time). If you, however are into your BBQs then I can see the merits of coal. It's more authentic, more of a process, easier to get that smoked taste and I guess the 'proper' way of doing it.
I personally can't see the point of using coal because I don't BBQ much and when I do, although I like the process, standing in the pissing rain, trying to light the coal and waiting for the coals to settle isnt my idea of fun.
Totally understand why folk do coal and equally why those who prefer gas.
Do I think with most things it matters to the eventual outcome? Not really from experience. A decent cook will produce great food regardless of what they cook on.
What matters at the end of the day is that you cook food that people and you enjoy.
To bring this discussion back around to actual cooking, I own a Weber Genesis gas, and a Weber performer kettle - with the propane starter. I think that grill is the most convenience you can get in a charcoal cooker - I can get it started in no time.
Flavor aside, the main thing I just can't seem to do acceptably with my gas grill is sear steaks or chops. Maybe I'm doing something wrong, but the thing just doesn't get anywhere near as hot as my charcoal - and when searing meats, it really makes a difference. When I'm searing stuff, I don't care at all about grill lines, etc. I want a nice even char across the whole thing, with a soft medium rare center. When I sear with my gas grill I get grill marks, but no char taste - it's just not hot enough. When I light a whole chimney of coals and put some steaks right over it - the thing is nicely charred (not burned) after about a minute per side. I then slide it to the indirect side, close the cover, and cook to med rare. This just doesn't work for me with the gas grill, and is actually how my whole question came about.
Flavor aside, the main thing I just can't seem to do acceptably with my gas grill is sear steaks or chops. Maybe I'm doing something wrong, but the thing just doesn't get anywhere near as hot as my charcoal - and when searing meats, it really makes a difference. When I'm searing stuff, I don't care at all about grill lines, etc. I want a nice even char across the whole thing, with a soft medium rare center. When I sear with my gas grill I get grill marks, but no char taste - it's just not hot enough. When I light a whole chimney of coals and put some steaks right over it - the thing is nicely charred (not burned) after about a minute per side. I then slide it to the indirect side, close the cover, and cook to med rare. This just doesn't work for me with the gas grill, and is actually how my whole question came about.
Demosthenes9
is One Chatty Farker
- Joined
- Apr 29, 2010
- Location
- Louisville
You'll never get that kind of char from a gasser as it's very design prevents it. One exception is if your gasser has a sear burner. The best you can do is to get the grill marks that you mentioned, and the best grill marks will come from cast iron grates. Preheat the grates long enough and that grill marks will be nice and crusty.
Another route to travel is using Grill Grates and flipping them over so that the flat side is up. In essence, it's like cooking in a flat bottom pan at that point.
Get a better gasser and you can sear the bejeebus out of a steak. A Lion gas grill will sear steak just as effectively as a kettle.
Why you would do that is a different question. Webers are designed to allow a novice cook to have success cooking. Professional grade gas grills will sear very well. Still won't taste like wood fire though
Why you would do that is a different question. Webers are designed to allow a novice cook to have success cooking. Professional grade gas grills will sear very well. Still won't taste like wood fire though
Cabin fever so soon.....
Having actually read the OP now :roll:, let me just add a few comments. Every piece of fuel contains a certain amount of heat. These are all calculated and known via chemistry. How that heat is released is another matter. The heat in charcoal and the equivalent heat in gas will give you the same temperature. You can increase the amount of heat released by burning more fuel, just the same as you increase the speed of your car by giving it some more gas. Of course if you put two charcoal briquettes in your smoker, you'll have twice the heat potential as one briquette, but if these are placed together, then probably they will not burn as rapidly as the one briquette (you also have to be concerned with increased losses due to higher temperature, but more about that later), so the heat is distributed over a greater period of time and the resulting temperature would be less than two times. You can increase the rate of burning by increasing the amount of oxygen the flame receives by opening the vents. While increasing the rate of burn, this also increases the heat loss in your chamber. There is a reason they have do not place near open flame warnings on oxygen tanks. The oxygen doesn't burn, but it causes whatever is on fire to burn VERY rapidly and it will get extremely hot. I haven't seen anyone attach O2 tanks to their smokers to get a good sear yet, but I wouldn't be surprised if there are youtube videos.
The other factor in the equation is heat loss. If you have a very well-insulated cooker, and no heat escapes, then that temperature will just keep on rising. All real-world pits have heat loss. A stable temperature is achieved when the rate of heat loss equals the rate of heat produced -- in physics, we love steady-state solutions where losses balance gains and we can use equal signs. Generally, the amount of heat loss is proportional to the surface area of the pit. The bigger the pit, the greater the heat loss. If you have a great big pit, you're going to be burning a lot of fuel to get that same temperature. This is the advantage of insulation (and ceramic smokers). I know my heat loss is small on my Oval as I can put my hand on it and not burn myself. My major heat loss is through my vents. Of course there are additional energy sinks, like what is required to actually cook the meat you have in the pit, but I think these usually are relatively minor.
Other factors to consider are the type of pit. If you have an offset, your firebox is external and very hot compared to the rest of your pit. Heat loss is proportional to temperature differences. If you have a hot pit, you burn through a lot more charcoal, than if you have a cooler pit. You lose heat much more rapidly from the hot firebox than from the meat section (sizes being the same). This is why offsets tend to burn a lot of fuel and why they are difficult to use in winter. In winter, I can run my offset for about 3 hours at 250* on a load of fuel. However, if I reduced the temp to about 190*-200*, I could go all night and almost cook a pork butt. Not only do I save fuel, but I get a good night's sleep. Adding insulation helps tremendously. A thin gap of air between two sheets of metal, for instance, can cut your heat loss through the sides by 80%. Think of the argon gas in your insulating windows.
As the comments in this thread suggest, there are many more important factors than gas and charcoal.
The other factor in the equation is heat loss. If you have a very well-insulated cooker, and no heat escapes, then that temperature will just keep on rising. All real-world pits have heat loss. A stable temperature is achieved when the rate of heat loss equals the rate of heat produced -- in physics, we love steady-state solutions where losses balance gains and we can use equal signs. Generally, the amount of heat loss is proportional to the surface area of the pit. The bigger the pit, the greater the heat loss. If you have a great big pit, you're going to be burning a lot of fuel to get that same temperature. This is the advantage of insulation (and ceramic smokers). I know my heat loss is small on my Oval as I can put my hand on it and not burn myself. My major heat loss is through my vents. Of course there are additional energy sinks, like what is required to actually cook the meat you have in the pit, but I think these usually are relatively minor.
Other factors to consider are the type of pit. If you have an offset, your firebox is external and very hot compared to the rest of your pit. Heat loss is proportional to temperature differences. If you have a hot pit, you burn through a lot more charcoal, than if you have a cooler pit. You lose heat much more rapidly from the hot firebox than from the meat section (sizes being the same). This is why offsets tend to burn a lot of fuel and why they are difficult to use in winter. In winter, I can run my offset for about 3 hours at 250* on a load of fuel. However, if I reduced the temp to about 190*-200*, I could go all night and almost cook a pork butt. Not only do I save fuel, but I get a good night's sleep. Adding insulation helps tremendously. A thin gap of air between two sheets of metal, for instance, can cut your heat loss through the sides by 80%. Think of the argon gas in your insulating windows.
As the comments in this thread suggest, there are many more important factors than gas and charcoal.
Last edited:
NickTheGreat
is One Chatty Farker
- Joined
- May 8, 2012
- Location
- Iowa
I think the only reason BTU's are used (in grilling world) is to compare gas grills. As in, Grill A with a higher BTU rating can get hotter than Grill B with the lower rating. It is telling you 'how much gas' that grill can add to the fire.
But to try to compare charcoal to gas with BTU's is wrong.
How many miles per gallon does charcoal get? The answer to that depends on how much coal, and how efficient the kettlemobile is. Just like gasoline.
But to try to compare charcoal to gas with BTU's is wrong.
How many miles per gallon does charcoal get? The answer to that depends on how much coal, and how efficient the kettlemobile is. Just like gasoline.
robbq
is one Smokin' Farker
- Joined
- Jun 3, 2012
- Location
- Westboro...
So since you were just asking about the science, not the cooking, I poked around the web a bit. Some of the reviews of lump charcoal on nakedwhiz.com mention the temperature they achieved burning a specific brand of charcoal and these seem to top out a little above 1000F. I believe they do all their testing in kamado cookers. I saw other mentions on the web of charcoal maxing out around 700C/1200F.
For a specific cooker, I think adding more fuel would raise temp to a point, but at some point you would either choke the cooker with too much material, or reach the limit of what the available airflow can do.
So if you built a charcoal fire in the open air, adding fuel should make it hotter till it reaches the limit of what charcoal can do. I don't see a lot of hard science on the web but it seems like a given material has a max temp it can achieve when burning and you can't exceed that just by adding more fuel.
For a specific cooker, I think adding more fuel would raise temp to a point, but at some point you would either choke the cooker with too much material, or reach the limit of what the available airflow can do.
So if you built a charcoal fire in the open air, adding fuel should make it hotter till it reaches the limit of what charcoal can do. I don't see a lot of hard science on the web but it seems like a given material has a max temp it can achieve when burning and you can't exceed that just by adding more fuel.
I never quite know what to think when I see measurements of temperature. There are a lot of variables involved. You can go back to the old reliable. When we were kids, we knew the bluer the flame, the hotter the fire. This is based on sound physics, Planck's Law. The spectrum of (color) depends on the temperature of the object you're looking at. Your eyes are very clever at integrating, but you can see in the graph below
The 5000*K temperature has a peak at about 500nm and to us appears white as it contains roughly equal amounts of red and blue. as the temperature decreases, the peak shifts to higher wavelengths and the color appears redder.
