OK guys I may be able to help here.
1 watt = 3.412 BTU's (rounded off)
1 BTU is the amount of energy required to raise 1 pound of water 1 degree (I am told it takes the same amount of energy for meat)
1 gallon water weighs approximately 8.34 pounds
say you want to bring 1 gallon of water to boiling from room temp. (68 degrees)
212 - 68 = 144 (difference in temp) 144 X 8.34 = 1200.96 (BTU's required to boil 1 gallon water)
1200.96 / 3.412 = 351.981 watts
So it takes 351.981 watts to boil 1 gallon water or 8.34 pounds meat
so as you can see there 650 watt element can only heat approximately 16 pounds meat
Keep in mind that Watts is a measure of power. Power is the rate at which work is done. BTUs is a measure of energy, not power. BTUs per hour is what equates to Watts, because then, they're both measures of power, or the rate at which work is done.
It makes sense that, since meat will be quite high in water content, you'll be pretty close if you consider a pound of meat to be similar in heat capacity to a pound of water. Water has an extremely high "specific heat" or "heat capacity per unit".
Anyhow, when making these calculations, just keep in mind that we're talking about the rates at which this "work" can be done. A 1200 Watt heater will raise the temperature of any given load twice as quickly as a 600Watt heater would.
So it's not really accurate to state that it will take 352 Watts to boil one gallon of water. Instead, assuming perfect heat transfer and perfect insulation, 352 Watts would boil that gallon of water in exactly one hour. Thus, 700 Watts would boil it in half an hour, and 1400 Watts would boil it in 15 minutes, etc., but they'd all surely boil it - eventually - if the conditions were correct.
And a 650 Watt element would cook more than 16 pounds of meat, but it would just take longer than a 1200 Watt element might.
But even that isn't really a good analysis of what would happen in a smoker.
The problem is that we will never get (nor want) perfect heat transfer from the heating element into the meat. Instead, the heating element heats the air in the smoker. That hot air does the cooking by transferring heat into the meat. So what we really want is for the heating element to raise the temperature of the air in the smoker surrounding the meat to whatever the desired temperature might be.
All of the calculations and recipes assume that we can control the air temperature surrounding the meat to whatever is called for. If the recipe says to run the smoker or oven, at 210 degrees F, then it doesn't matter how much meat you have in the smoker as long as the heater can raise the air temperature to the desired setpoint.
BUT, the amount of meat in the smoker, how moist it is, the shapes of the cuts, etc., will determine how well the heat load of the meat is coupled to the air in the smoker. And the amount of air flowing through the smoker will have an effect. And finally, quality of the insulation in the smoker will also determine how much actual heat load will be placed on the heater as it tries to maintain the air temperature setpoint.
The air won't transfer its heat to the meat instantly or efficiently. Air is a relatively poor way of coupling heat into the thing being cooked. The heat transfer is relatively poor.
You can stick your arm into an oven whose air temperature is 350 degrees, and you won't be burned - at least not right away. Try sticking your hand into a deep fryer set to 350! That's the beauty of deep frying. You have a fantastic heat-transfer medium, with quite a bit of heat capacity, and when you put the food into that hot grease, it the heat transfer happens very rapidly. The same is true of water. Put a hot-dog into boiling water, and it'll cook in no time. Put it into air at that same temperature, and it'll bake slowly.
Anyhow, just remember that heater power and "meat load" are not the only things involved in these calculations. You also have the heat transfer calculations, and with air as the heat transfer medium, there's quite a loose coupling between the heating element and the meat. They're not tied together well at all.
I know that was long-winded, but I think it's important to have a good mental model of what's going on in an oven or smoker, etc., when you're visualizing where to place the meat, how to arrange it, etc. And this plays into the discussion I've seen in this thread of MB moving the location of their vent opening, etc., to try to eliminate hot or cold spots.
I do a lot of work on incubators and ovens for laboratory work, and believe me, if you don't have a fairly potent circulating fan, the air temperature, even in a very precision incubator or lab oven can vary wildly from place to place within the oven.
I'd guess things to be pretty uneven in any of these smokers, but moving the vent may be a very good thing, indeed, in the new design.
I ran across this site because I just got one of the 2011 model 40" smokers at my Sam's Club last night and did a web search for answers to some questions I had. They had quite a stack of them, so I think they're actively selling the old model right now. I now kind of wish I had waited for the new model, but then again, I don't want to miss out on many months of smoking.
I got the smoker on a whim because I'd bought a pork butt and wanted to smoke it, but didn't want to babysit a charcoal smoker all night. So it makes sense to buy a whole smoker just to do one piece of meat, right? ;-)
Anyhow, I figure I can modify this unit if necessary, and I'm glad to have run across this forum. Lots of great info.
The butt did come out very good, although I'd have liked more smoke. But I didn't babysit it at all. It only got one "batch" of hickory chips at the very start. My wife preferred the very light smoke flavor, while I'd have gone for a lot more. I'd already come to the conclusion that I should have gotten up and added more chips every hour or so for a while, but it seems to me that you'd need to open the door and dump out the coals every time because there would be no room in the wood tray without doing that. The coals don't emit any more smoke, but they still take up the precious space where you'd need to put in the new batches of chips.
But an advantage of opening the door each time would be that the heater would be forced to come on strong for at least a short time right after you added the new chips each time, so you'd get a burst of smoke right then as the unit tried to recover the set temperature.
After reading this thread (the first and only one I've read here), I suspect I may want to get one of the A-MAZE-N-PELLET-SMOKER gadgets so I won't have to babysit things.
I do really like the fact that I was able to put the pork butt in last night at about 02:30, and then just sleep, and then abandon it again after I woke up and needed to be somewhere else all day, and then get to come back to a nicely cooked bunch of meat about 14 hours after I'd started it. I did wrap the butt in foil before I left for the day - about 8 hours into the process.
I'll do more reading on here now. Great forum, everyone!
Thanks for the reply! i noticed the model number on the sams club one is 20070810. Heres the link:
http://www.samsclub.com/sams/shop/product.jsp?productId=prod1180971&navAction=push
Anyone can explain what the deal with the model number boogie here? Post a pic when you can to see the goods :)
The Sam's website is incorrect on the model they specify. Again, what I got, just Saturday evening, was actually a 20070211, not whatever they have listed on their website right now.
Hi all...1st time poster. Anyway, I also saw the model # 20070810 on Sam's web site. I visited my local Sam's yesterday, and the model they had on the floor was a 20070211. I looked at the manual that came with it, and it said it covered model #'s 20070211, 20070311, and 20070411. This is the first time I've heard of a 20070211...anyone aware of this model?
That's exactly what I got. I suspect that's what Sam's has in their supply chain right at the moment. I guess it's last year's model.
Anybody's local Sam's club have the new ones in yet?
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Not if my experience is typical.
