Convection ovens move air around as they cook, speeding cooking time so you spend less time in the kitchen. Most convection ovens are electric and it's rarely an option for a gas oven. Understand the basics of when and how to best use convection or conventional cooking in your kitchen.
The fan inside a convection oven makes it stand apart from a standard conventional oven. A conventional oven only has two heating elements: the top and bottom of the oven box, which provide radiant heat to cook the food. Radiant heat from only two elements results in hot and cool spots in the oven. By using a fan to move around the hot air, a convection oven generally has an even temperature inside the oven box, which ensures items cook more quickly and more evenly. This even temperature allows you to cook more food in a convection oven. A conventional oven usually limits you to two cooking racks because a third rack in the middle won't have direct access to the radiant heat of the elements and won't cook as quickly. In a convection oven, the fan ensures items on the middle rack cook at the same rate as those nearest the elements.
Convection Oven Types
A true convection oven has a third heating element near the fan, so only heated air is blown into the oven. These models also are called third-element or European convection. Ovens with an interior fan but only two heating elements still are convection ovens, but they do not heat as evenly as those with the third element. Your oven may have hot and cool spots, especially near the top and bottom elements. Avoid convection ovens with an outside mounted fan. The fan blows cold air into the oven instead of using the hot oven air. These convection models cook more unevenly than a standard conventional oven because of cold outside air mixing with the hot oven air.
Choosing a Setting
Almost anything that cooks well in a conventional oven will cook well in a convection oven -- with a few exceptions. Continue to bake loose batters such as cake and quick breads, or any runny items such as one-crust fruit pies or casseroles containing a lot of liquid or gravy, on a conventional oven setting. The moving air from the fans will blow runny items around, resulting in a messy oven and a lumpy cake top. Broiling usually is only available in conventional ovens, with a few exceptions. Otherwise, cookies, yeast breads, meats and vegetables all cook more evenly and more quickly with convection. A third pan of cookies bakes just as evenly as two, and breads come out evenly browned with soft interiors. Vegetables caramelize more quickly and meats brown more evenly while remaining juicy inside.
Unless your recipe specifies convection temperatures, you will have to make adjustments. "LA Times" food journalist Noelle Carter recommends lowering the oven temperature and shortening the cooking time by 25 percent. Some ovens may vary, so check the food for doneness before removing it from the oven and adjust the time accordingly. This works in reverse as well. You may increase the cooking time and oven temperature by 25 percent if you are preparing a convection recipe in a conventional oven. Depending on your oven, you may be able to tun the convection oven on and off as needed, which allows you to speed up cooking near the end if your roast is cooking more slowly than expected. You may be able to use the convection setting with just the broiler on some models.