Please explain convection cooking

Lostinmadnez

I have been googling around regarding the Eggs convection "capabilities". And am more confused than before.

Does it mean that the hot air circulates back "down" between the firering and outer shell? And then back up through the firering?

There is a komodo grill that lacks the space between the ring and the outer shell, yet exhibits similar good cooking as the BGE. And normal Webers also "circulate" the air back down through the coals.

Please help me out. Or is convection happening inside most grills anyway?

gerhardk

Convection cooking is were the heat transfer becomes more efficient because the hot air moves around the food.  In a convection oven you generally have the elements outside the cooking chamber and then circulate the hot air by the use of a fan.  I think in the case of the egg it is that the plate setter blocks the radiant heat and the hot air moves past the food aided by the draft created from the egg being airtight, so it has to come in through the bottom vent and exit through the top.

Gerhard

gdenby

This is just my opinion. While there is probably a little more convection going on in an Egg than ordinary oven, I doubt it compares to a oven with a fan. The amount of air that comes out of my kitchen range is larger than that from my Eggs at the same temperature. I have to think the air is swirling around in the Eggs more than in the stove. But at low temperature, indirect cooks, a thermometer near a piece of cold meat will report a lower temperature than the dome therm. So there is not enough airflow to push that cool, moist cloud from around the meat.

Botch

Yup, both a convection oven and the Egg (and, for that matter, a gasser) cook by convection, moving hot air over the food.  The Egg can also cook by radiation (hot coals blasting IR radiation onto the food, which doesn't happen when a place-setter is used, or a drip pan) and a very small amount of Conduction (the blackening done by CI grates, or anything cooked in a vessel).  

SteveWPBFL

Heat transfer potentially involves three components; convection, conduction, and radiation.

I sat in thermodynamics class for a year and learnt this 30-some odd years ago.

Convection is heat that is transferred from surrounding media, for a BGE typically the air that flows into the bottom vent heats up from the coals flowing up to the cooking target and then out the top.

Conduction is heat that is transferred through an adjacent mass having contact with the cooking target, for a BGE typically a hot grid, pan, stone, platesetter, or plank.

Radiation is heat that is emitted from the heat source, for a BGE typically the hot coals that have direct line of sight to the cooking target.

On a BGE you can have all three or maybe knock it down to just convection. Direct cooking provides all three. Indirect cooking minimizes radiation. You can play around with minimizing conduction in an indirect set up and cook mainly with convection.

Hope that helps. Goo Goo Ga Joob!

SteveWPBFL

One more things.

Radiation tends to cook fast for a hot fire, and raising the grid is one way of reducing that effect.

Convection, cooking via the air, is the slowest method for a given temperature. Air doesn't hold a lot of heat.

Conduction can be fast or slow depending on the adjacent media, it's heat transfer characteristics, mass, and temperature. You usually use the stovetop for high conduction cooking and use a BGE to reduce or minimize that component.

Sorry, 2nd cup of coffee talking.

Flamethrower

Forgot # 4 -Direct flame contact

Baysidebob

I bought my wife a fancy-dancy gas convection oven and she loves it. The fan keeps the temp uniform throughout. The difference between grid and dome temp, whether direct or indirect, indicates the egg is not a “convection” Q. Attention and perhaps turning are still required. “Attention” is the key. “Set it and forget it” is not barbecue. “Don’t get too drunk to watch it” is barbecue. The BGE is way ahead of any other Q for stability but using it is still an activity that requires attention and that’s the whole point.

SteveWPBFL

Yeah, right! The flame itself, which is really from the products of combustion, i.e. the oxygen in the air and the charcoal (fuel). That's where the heat is really generated! Thanks.