Below is some of our research into the topic of cooking with a convection oven. Please keep in mind that our recipes are developed using ovens on their non-convection or ‘traditional’ mode.
What is Convection Heat?
Convection is the process through which heat is transferred by the circulating motion of air or liquid. In a convection oven, a powerful fan located in the rear of the oven blows air over the heating element and keeps the hot air in constant motion. This constant circulation not only speeds up cooking but results in very even cooking, whether the food is on the top rack or the bottom rack and whether it is being baked, roasted, or broiled.
Manufacturer instructions for using convection ovens generally recommend setting the temperature 25 to 50 degrees (Fahrenheit) lower than a recipe directs for a conventional oven and reducing the cooking time by 30 percent. While this is a good rule of thumb, if you own a convection oven, make sure to check the manufacturer's guidelines that came with your oven.
How does a convection oven work?
A built-in fan circulates the hot air, which helps to maintain a constant temperature and eliminate hot spots. This should translate to even browning and faster cooking because the hot air fully engulfs the food and conveys the heat more efficiently than it does in a standard oven, where the hot air does not circulate. Most ovens with a convection feature are equipped with at least two convection settings: convect bake and convect roast. In the former, a majority of the heat is generated from the lower heating element to mitigate surface browning. In the latter, heat is generated from both the upper and lower heating elements to promote the surface browning desired in most roasted preparations. In our tests, we used the convection setting appropriate for the preparation and in some cases tested both. Manufacturers recommend reducing the oven temperature by 25 to 50 degrees when using a convection setting, and we incorporated these temperature adjustments into our tests.
The following is a review of our findings. Of course, these tests represent just the tip of the iceberg; we intend to make convection oven tests an ongoing project.
CAKES
We found no advantage to baking yellow layer cakes on the convect bake setting. In the convection mode, the cakes required a 25-degree temperature reduction to prevent the surfaces from becoming dry and leathery. This temperature adjustment slowed baking by several minutes, with no improvement in the cakes.
COOKIES
With the oven temperature reduced 25 degrees, cookies baked up nicely on the convect bake setting, but the baking sheets still required top-to-bottom shuffling. (When we lowered the temperature by 50 degrees and extended the baking time, we found that the cookies browned evenly without switching the position of the baking sheets. We are, however, hesitant to recommend a universal 50-degree temperature reduction when baking cookies on a convection setting. Attempt this at your own risk.) We found that cookies that are better baked one sheet at a time in a standard oven--such as our Molasses Spice Cookies--can be baked two sheets at a time on the convect bake setting.
ROAST CHICKEN
Chickens roasted on the convect roast setting were done 10 to 15 minutes ahead of those roasted in a standard oven, and the skins were darker and more evenly browned. Chickens roasted on the convect bake setting also cooked faster, but they did not brown any better than in a standard oven. Stick with convect roast. No temperature adjustment is necessary.
YEASTED BREAD
When we baked free-form rustic loaves on preheated baking stones, the convect bake setting yielded a loaf with a slightly thicker, crispier crust. The loaves browned and rose on par with each other, indicating that no time and temperature adjustments are necessary.
PREBAKED TART SHELL
With the oven temperature reduced 25 degrees, tart shells lined with foil, filled with pie weights, and prebaked on the convect bake setting browned a bit more quickly than tart shells baked on the standard bake setting. Once the foil and weights were removed and the shells returned to the oven, the bottom of the convection-baked tart shells browned better and more evenly.
TO SUMMARIZE:
Convection settings do promote even browning and work well for preparations in which browning and crisp surfaces are desired. Temperature reduction is necessary for more delicate and sugary baked goods such as cookies and tart shells but not for sturdier, more savory foods such as roast chicken and yeasted breads.