Convection vs Conventional Temperatures
I am curious about convection baking temperatures. In this thread from Eric's blog, SylviaH notes that her oven runs 10-15 degrees hotter on convection than it does on conventional baking. My oven does just the opposite, running a good 20-25F lower on "Convection Bake" than it does on the conventional "Bake" setting. I usually preheat in convection mode because it seems to heat up faster, but when I switch from convection to conventional the indicator always show 25F less than the "set" temperature, even though the oven has "said" it is up to temperature (it beeps). This is reinforced by the oven slowly ratcheting up the temperature those 25 degrees, to finally indicate once again that it is up to temperature.
If you use convection bake, what actual oven temperatures do you see at a given "set" temperature?
OldWoodenSpoon
As I understand it, Convection is heated differently than Conventional. The heating unit in Convection being attached to the blower or fan unit. Conventional is coils above and below the oven, sometimes covered sometimes exposed. When switching from convection to conventional, the heating coils need time to heat up and trasfer that heat to the inside of the oven. This will lead to a drop in the oven temperature and maybe the thermostat indicatations. The convection temp settings are many times slightly lower than temp because of the use of the blower to increase heat -- moving air is hotter than non-moving air. (Older convection ovens tend to blow hotter.)
One way I avoid the heat sink is to pre-heat with convection using upper and lower heat. If that is not an option, first pre-heat with convection and then 10-15 minutes before putting the bread in the oven, switch to conventional heat so the oven coils/walls/cavity can heat up.
Caution: this also means that if you turn the convection back on after using conventional heat, the oven may be hotter than it indicates or your expectation. :)
I have a Jennair oven with either conventional or convection capability. Whatever baking temperature I choose, it automatically lowers the temperature by 25 (or is it 50?) degrees F when in convection mode. That lets me use the convection feature while following recipes written for a conventional oven, supposedly saving me the mental gymnastics of remembering to lower the temperature on my own.
Paul
It is also possible to reduce the baking time by about 15-20%. So if you are running the oven in convection mode but are using a conventional recipe, reduce the time. A 40 minute baking time becomes about 32 (-20%) minutes. That way you don't have to do mental gymnastics and guess temperatures.
David
@Mini Oven / @PMcCool - With my oven I think it is more a case of what Paul points out. My oven lowers the temperature by 25F on convection and then cycles up and down. When I change modes, or adjust the set temperature, it shows the current oven temp and you can watch it change up or down till it gets to the new set temp. Going from convection to conventional always results in the display showing 25 degrees lower than the set temp, exactly as Paul describes. However, I think you have a meaningful point Mini, in that it must take that convection heating element some time to heat up after being selected. Even though I have not noticed the temperature indicator dropping after the mode change, you have probably pointed out why my oven seems to take so long to start making up that 25 degree lag. Thank you both.
@breadmantalking - I think that because my oven seems to automatically adjust the temperature, there is no need to adjust the cook time. I always cook to an internal temperature target anyway though, so I also always start with 10-15% less time on the clock than is called for by the recipe, and I watch the bake as it progresses. I don't worry too much about the cook time as a result. I get it though: you must adjust one way or the other, on either time or temperature because convection exerts something like a "negative wind chill" effect in the oven.
Thanks to all for the enlightenment.
OldWoodenSpoon