After an ElectricKit conversion to your aga, you may find dishes of food/ baking can burn on the bottom of the top oven, or burn at the top of the bottom oven. This article will help you understand why this happens, what you can do about it, and how it can be turned to your advantage.
Why it happens
This effect happens because of how heat gets into the ovens. The heat source for the two main ovens (in a two or four oven aga) is an electric element located between them. When the top oven temperature is set on the display unit, the element will ‘fire’ (have electricity put into it to heat up), and the temperature set will be achieved after a certain time. Once the desired temperature is reached, the element between the ovens will only fire in short bursts to keep the temperature stable.
While the element between the ovens is firing, it will produce more heat at the bottom of the top oven, and at the top of the bottom oven. This will have an impact on any dishes resting directly on the bottom of the top oven, or placed near the top of the bottom oven.
When the element is not firing, the both ovens will quickly stabilize their respective temperatures throughout the oven space.
The element firing may produce a hot spot area within the oven floor, as this is the nearest part of the oven to the element, so will heat the quickest. There will be a short term temperature differential in the oven, until the temperature sensor at the top of the oven reaches the required temperature. When it does so, it switches the element off, and the oven will quickly stabilize in temperature throughout its height and depth.
While the element is firing, any dish of food left resting on the bottom of the top oven will get heated more than the surrounding air, as it is closest to the element. This can result in a ‘burned bottom’, where the bottom of the food is heated more than the top. Turning up the oven to increase the temperature of the oven will result in the element firing more, and the problem getting worse.
A good way of avoiding this is to raise whatever you wish to cook slightly off the bottom of the aga oven by creating a small air gap. This can be accomplished by placing the metal ‘baking tray’ plate, or a baking grill that come with the aga, on the bottom of the top oven, then place the dish you want to cook on top of that.
Avoid opening the oven door lots of times, as each time this is done, some heat will be lost. When the door is shut again, the thermostat will fire the element to get the oven temperature back up to the temperature set, and this may produce a temporary hot spot on the oven floor, until the oven temperature has stabilized again.
You cannot directly set the bottom oven temperature, and as a rule of thumb it will be at approximately 70% of the temperature set on the top oven display.
When the element between the ovens fires (to keep the top oven temperature at the desired temperature setting), the top of the bottom oven will get hotter more quickly than the bottom of the oven, as it is nearer to the element. The impact of this is that some items of food may burn on top and not be as cooked underneath. Once the element has stopped firing, the oven will quickly reach a uniform temperature throughout.
As previously mentioned, opening and closing the top oven door will result in heat loss in the top oven, and the thermostatic control system will respond by firing the element. This in turn will have an impact on the bottom oven, particularly near the top.
A way of reducing this effect and stabilizing the bottom oven temperature is to place the baking tray (metal sheet) near the top of the bottom oven, to create an air gap between the top of the oven and the plate. This will reduce the amount of direct heat radiated downwards onto food below the plate when the element is firing.
Using this effect to your advantage
The temporary rise in temperature near the top of the bottom oven when the element fires (in response to the requirements of the top oven) can be used to produce a 'grilling' effect. Roast potatoes can be crisped up using this method, as can the tops of lasagnas or anything that you want to ‘brown’.
You can initiate this effect in the bottom oven by raising the oven temperature setting on the display by 10 -15 degrees centigrade. This is usually enough of a rise to produce a grilling effect for approximately 15 minutes.
If you are going to do this, just be aware of what is in the top oven, as it will be heated from the bottom until the temperature set is reached.
Here is a summary of how to minimize burning food on the bottom of the top oven, or at the top of the bottom oven:
1. Keep to a minimum opening of the oven doors during cooking, as this will result in heat loss, and the element firing to compensate.
2. Place the metal baking tray or grill on the bottom of the top oven to create an air gap between dishes and the bottom of the oven.
3. Place the metal baking tray at the top of the bottom oven to create an air gap, and any food to be cooked underneath this.