What Is a True Convection Oven?
A true convection oven is a type of oven that uses a fan to forcibly circulate air inside the oven enclosure, allowing foods to cook faster and more evenly and to brown better than in conventional ovens, which lack fans. The term "true" when applied to convection ovens is somewhat misleading. Many convection ovens have two heating elements, much like conventional ovens. Some finer, more expensive convection ovens add a third element, mounted near the fan, which heats the air as it is circulated directly from the fan. Some people believe and insist that only convection ovens with this third element are true convection ovens, although any oven with a fan that circulates the air in the oven enclosure is technically a true convection oven.
In physics, the term convection refers to the motion of gas or liquids within a system due to temperature differences, resulting in heat transfer within the system. When applied to convection ovens, this word takes on a slightly different meaning, referring to the transfer of heat to foods by the circulating hot air. Air that is in motion transfers heat more efficiently than still air. For example, blowing on a bite of hot food cools it more quickly. A convection oven uses the same principle but to add heat to food rather than to take it away.
Modern ovens generally use either electric elements or gas burners to generate heat. Convection ovens may use either of these sources of heat but rarely, if ever, use both. A true convection oven, however, even if powered by gas, uses considerably more electricity than an otherwise comparable conventional oven because of the fan. This is ameliorated somewhat by the fact that convection ovens generally cook considerably faster than conventional ovens. Convection ovens with a third heating element mounted near the fan will work slightly better than those with elements in the traditional top and bottom arrangement.
Cooking times in a convection oven, as compared to a conventional oven, may be reduced and the food cooked at a similar temperature. The temperature can also be lowered and the food cooked for a similar amount of time. The level of the reduction varies depending on the oven, the food being cooked, and the type of pans or dishes being used to cook the food, but the temperature can generally be reduced by approximately 10% or the cooking time by about 20%. Most convection ovens will have an automatic shut off for the fan that engages when the oven door is opened and a manual shut off that allows the oven to be used as a conventional oven.
Foods prepared in a true convection oven, especially roast meats, will develop a brown crust faster than in a conventional oven, sealing in juices and preventing the meat from drying out. Convection ovens also tend to cook more evenly than conventional ovens, reducing the need to rotate dishes from shelf to shelf when cooking several dishes at once. While true convection ovens have many advantages, they also have some drawbacks. They are more expensive than similar conventional ovens and have more components, which may make them more expensive to repair. Convection ovens are also usually noisier because of the electric fan.
Hah! @Markerrag, Whatever works for you and your wife! My wife and I have a similar arrangement except we take turns cooking and whomever doesn't cook is on dishes.
A couple of thoughts that I hope are helpful. Considering the three ways of transferring heat, Conduction (physical contact), Convection (through gas, such as air, or liquid), and Radiation (infrared), I don't think it is accurate to say everyone has a convection oven (am I understanding you correctly Anon1000335?). If you have a conventional oven, the primary method for heat transfer is radiation--heating element gets hot and heat is transferred to your food via infrared waves. True, that some of the infrared heats the air, which then heats the food, but since the air is stagnant in a conventional oven, heat transfer through air is not the primary method. Convection ovens, on the other hand, transfer heat via air by circulating it with a fan, in addition to the typical radiating heat from the elements/burners.
My second thought comes from an article I read on amazingribs.com where a food scientist debunks the long-held myth that searing meats seals in the juices. It doesn't. As temperature is applied over time, meats lose moisture. No crust or sear can stop this. The secret, as @Markerrag mentions has to do with time and temperature. Cook a turkey past 165F for white meat and 175F for dark and it loses too much moisture and becomes dry and tough. Pull it out of the oven at 160-165F, and you will have a properly cooked but still moist turkey.
Just yesterday, I cooked two turkey breasts tenderloins in my convection oven at 250F until they reached 160F (I wrapped these in foil with a few tablespoons of butter from 130F-160F, borrowing a technique from the low-and-slow barbecue crowd), and the result was an incredibly tender, juicy, and flavorful meat. These cooked for about 2 hours total, though the time was secondary to the internal temperature. Had I cooked these too fast or to a higher internal temperature, the results could have been an overcooked exterior with an undercooked interior or a dry and tough turkey.
Everybody has a convection oven already, even if they don't know that they do!
The main thing is this- "Convection Ovens" as we know them now, have a fan and exhaust system, that circulates the hot air within the oven.
However, the name is totally misleading and a marketing ploy.
It should be rightfully known as a "Forced Air Convection Oven" because of the fan and exhaust system, but, in advertising terms, that comes off as cumbersome and not so "glamorous" hence the plain marketing term of "Convection Oven."
Of course the real reason why everyone wants a "Convection Oven" is to get their food done faster, even though they are using the wrong implements to do so, in the first place!
If you're using a roasting pan with a 4 inch depth, even though you have your turkey or whatever on a rack, the "forced air" has a really hard time of circumventing the edges because heat rises, remember? But if you have a 4 inch "fence", the heat will have a harder time of cooking your turkey on the bottom, and that can mess with your estimated cook time.
Also having a "Forced Air Convection Oven" is no guarantee of a "perfectly cooked turkey" as concerns internal temperature, which 95% of America still doesn't know about because of their lack of cooking knowledge!
I wasn't aware these existed. At my house, we've got a regular old oven (I suppose) and a wife that knows how to use it. I kind of stay away from it because I'd have trouble even boiling water.
Before you start yelling "sexist," I should mention that we have an arrangement around the house. My wife cooks, I do the dishes. Division of labor, see?
Post your comments