Convection Ovens

[sdnapier]

I am still confused about how they cook. Can anyone explain? Also, if you have one are there any limitations? Thanks, Sheryl

[Harry Chickpea]

Briefly - if you have a covered bowl of water in a 400 degree oven, the amount of time it takes to heat from 50 degrees to boiling is a function of the surface area of the bowl and the rate that heat can transfer through it to the water.

The heat is in a couple of forms - radiant heat from the heating element, and heat in the air in the oven. Ignore the radiant heat, as it is only secondary in most cases. Most heat comes from the heated air.

Effectiveness of heat transfer is increased by large differences in temperature.

The air that is nearest the bowl is cooled by the absorption of heat into the bowl and may get to 200 degrees or less. That means that it has less heat it can transfer than air at 400 degrees.

In a standard oven the design is that the cool air slowly sinks by natural convection currents, becomes heated by the coil or gas heated metal, and rises like the smoke in a chimney, going back up to the bowl.

In a convection oven, there is a fan that mixes and blows the air forcefully enough to remove that layer of cold air near the bowl and replace it with hot air. That means the water in bowl gets heated faster.

I used a covered bowl of water in the example because it is simpler. Foods like breads have more complex heating patterns and needs.

"Convection oven" is a misnomer, because the convection currents are being over-ridden. Fan forced hot air oven just doesn't have the marketing appeal.

[Michael W. Smith]

We were in the market for an oven and stopped by our local Lowes. There were two ovens sitting side by side - same name, same looks and one had been $100.00 more, but it was on sale.

We asked the lady what the difference was as they looked the same to us. "Oh the one of the left is a regular oven and the one on the right is a convection oven."

We kind of turned up our noses at the word "convection" and she said "Have you ever used a convection oven?" We told her no and asked what was the difference.

As Harry Chickpea has said "convection" is just a fancy name for an oven with a fan. The lady told us she has always used a convection oven but didn't have one in the house she lives in now, but is looking at getting one. She said she missed it because you could cook things faster and do it lowering the temperature.

She told us when using the convection (the fan) to lower the temperature by 25 degrees and to take about 1/4 of the cooking time off your regular recipe.

We bought it, but haven't used it (the convection part) yet.

Yeah, telling people it's "an oven with a fan" just doesn't have the marketing appeal. So they came up with the word "convection" because it sounds fancy.

[Chickensittin]

I have a convection oven and I love it. I find that my food cooks evenly and the oven doesn't have hot spots because the air is circulating. (Yes, it is an oven with a fan) I often bake 2 or more pans of cookies at the same time and they brown at the same rate. I don't have to turn the pans around or move them up or down on the racks.

[Crisste]

Convection ovens are far superior!!

[okiemom]

I have had an old chambers gas oven and a modern gas convection oven and really I liked my gas better. that said the chambers is very small and the convec tion can fit huge amount of racks. I still have to rotate sheets to get better browning even with convection.

[Paumon]

Originally Posted by sdnapier

I am still confused about how they cook. Can anyone explain? Also, if you have one are there any limitations? Thanks, Sheryl

I didn't want to get a big convection oven nor a microwave oven with convection capability, but I was curious enough to purchase and experiment with a small counter top convection oven. It's great for cooking uncovered foods that you want to get browned and form a sealed, crispy crust or layer on the outside. So for example, if I cook cut up pieces of potatoes or other root vegetables in it, it will seal the outside of them and they puff up like balloons as they are cooking but retain their inner moisture. If I cook chicken or other poultry pieces with the skin on, the skin will seal and crisp up and brown nicely, the pieces puff up like a balloon but the meat retains it's juiciness and moisture on the inside. Poultry without the skin on you have to be really careful that the meat doesn't dry out before it's cooked. Basting it very frequently helps.

Fish with skin on, steaks, chops and roasts will seal and brown on the outside, retain juiciness but they don't puff up the way poultry meats with skins on will do. Sausages and hot dogs cook and brown and puff up magnificently without splitting and they retain all their juiciness. Meats, fish and veggies all brown and cook faster in the convection cooker than they do in a conventional radiant heat only oven.

Eggs go rubbery and yucky.

A fruit pie with latticed top bakes up beautifully and quickly but I couldn't bake cookies or a cake or loaf of bread in it because they don't form a crusty seal on the outside. Because they don't seal on the outside the moisture inside gets sucked out far too rapidly and the dough or batter dries out long before the cake or loaf is even close to being properly cooked. Huge fail on those kinds of baked goods that require slower baking and not much loss of moisture.

Everything that I've had the most success with was not enclosed in a lidded container or wrapped in foil - they were all in open wide mouthed roasters or pots or sitting on open trays or racks above trays and exposed to the circulation of hot air moving over their surfaces.

[Molly Mckee]

The oven in my stove can be set for convection or not. I normally use convection. I think it works well for both bread and cookies as well as almost everything else, it's faster too which is nice.

[partndn]

Lots of good info posted.

I have one in my home. Can choose convection or not. I have seen it be useful when cookies or rolls that fill a pan that's about the size of the oven rack. They do cook more even. Otherwise, I don't use it much.

Now.. my church has a commercial one that ROCKS. I have used it many times and no lie, it cuts cooking time down. Lots of people are afraid to use it, but I love it. It has a low and a high setting. On high speed it's loud as a jet blower. Then we have some Viking gas ranges with normal ovens (drooooooool). Anyway..

My experience says the commercial market is a lot bigger difference than home models. Like some have said, the air moving effects your need to cover certain things,etc.

Home ones are probably not worth the price hike paid.

I have not done it, but the convection feature can be used on low heat just like a dehydrator. Could be bonus if you don't have one of those.

[Paumon]

Originally Posted by partndn

....... I have not done it, but the convection feature can be used on low heat just like a dehydrator. Could be bonus if you don't have one of those.

Yes, it can be used to dehydrate on low heat. If you are dehydrating very light weight items though (like herbs) it may be necessary to lay a piece of cloth or some kind of screen over top of them to hold them down and stop them from getting blown around inside the oven. The fan is that much more forceful but if that precaution is noted, they will dehydrate a lot faster in a convection cooker than they will in a conventional dehydrator.

[sdnapier]

Thanks everyone. I really appreciate all the info!!

[Savrens]

There are differences in convection ovens;

http://www.finecooking.com/qa/convec...onvection.aspx

[Savrens]

Another good article on convection ovens.

http://www.finecooking.com/articles/...ion-ovens.aspx

[sdnapier]

Thanks, Savrens. It's interesting to know that there is a European version.