What is the difference between "air fry", "convection broil", and "convection bake" (all in the same oven)?

Question

The answers to Is there a difference between a Convection Oven and an Air Fryer? all talk about the difference between a large oven and a small appliance.

But what's the difference when it's the same oven with optional settings?

For instance, I just bought a new LG (LSGL6337) gas range (top broiler, rear heater), which in addition to the normal bake setting, also has convection bake, convection roast, and air fry.

Setting	Description
bake	Bake is used to prepare foods such as pastries, breads, and casseroles. It is normal for the convection fan to operate periodically throughout a normal bake cycle in the oven.
convection bake	For more even mult-rack cooking of pastries, cookies, muffins, biscuits, and breads.
convection roast	Combines cooking with the convection fan to roast meats and poultry. The heated air circulates around the food from all sides, sealing in juices and flavors.
air fry	This feature automatically increases the entered temperature by 50F° for optimal performance

The descriptions are market-speak, and not very useful in reality.

All four modes will use the fan, and I can of course choose the temperature.

Does air fry do nothing more than increase the temperature to more than I asked for? That sounds like a feature the sales department requested.

And apparently, the two "convection" modes subtract 25F° from the requested temperature.

So even if the only difference between these is the pointless and confusing temperature adjustments (+50 or -25), that still doesn't explain what's different between the convection bake and convection roast modes.

What is the actual technical difference in behaviour between the various modes?

Answer 1

Without knowing the exact model of range and number/placement of heating elements (it could be 2 or 3), it is difficult to be absolutely accurate as to what the manufacturer means by these settings. I'm assuming here your range has just got a top and bottom element. It may possibly just have a top element and a fan element. If your range has 3 elements, hot air will also be emitted from the rear blower fan under certain settings.

As a rough outline, this is how each mode will distribute and focus the heat in a different way:

1. Convection bake - Bottom element + fan. Used for pies, quiches etc. that benefit from heating from below to prevent soggy pastry etc.

2. Convection broil - Top element + fan. Used for dishes you want to crisp up on top, e.g. Cottage pie, lasagne, pasta bake etc.

3. Air fry - Top + Bottom elements + fan. Used for rapid heating all round, foods such as chips, frozen nuggets, pizza etc.

Please note these are only guidelines, every oven is thermally very different and the best way (unfortunately) of evaluating each mode is trial and error.

For instance, in my oven if I were to cook a lasagne on setting 2, the top would be perfect and the bottom very al-dente, it is best for me to use this setting for the last 5-10 minutes of cooking. Yours may be very different.

For definitive answer, I'd try and source the original instruction manual online, unless it is very obscure or old. That will be your best guide.