During my research for toaster oven reviews I have noticed that people seem to be confused about whether or not you need to preheat an oven before cooking in it. I saw over and over where people were asking questions on the topic of preheating.
This got me thinking. I preheat my toaster oven but I don’t really know why I do that. Is it really necessary? What happens if you put your food in the toaster oven before it has finished preheating? I didn’t know the answers to these questions or others so I decided to learn all that I could about the topic of preheating.
What is the purpose of preheating?
The purpose of preheating is to heat the air inside the oven so that food can be cooked. Reaching the right temperature is needed so that food cooks accurately and thoroughly.
Do I really have to wait for my toaster oven to heat up before I put my food inside?
The short answer is – maybe. The long answer is that it depends on what you are cooking. Some foods, like toast and bagels, do not require preheating. The same is true for leftovers that you want to reheat. You can pop them inside and fire up your machine. Okay, not literally, you don’t want any kitchen fires!
However, if you are cooking foods that are to be baked or cooked, such as bread, cake, casseroles, chicken, or frozen dinners, it is important that you let your toaster oven preheat before you place the food inside. The reason why you need to wait is because cooking times do not include preheating.
What will happen if I start cooking my food during the preheat process?
Putting food inside a toaster oven before it has fully heated up can result in poorly cooked food. Here are a few examples of how foods may respond to being cooked too soon:
- Baking – Baked foods that use yeast, baking soda, and baking powder as leavening agents need precise temperatures to create the chemical reactions needed to create something edible. If you place dough or batter inside a cold or cool oven then there is a good chance that they will rise either too soon or too late. If you’ve ever baked a cake and had it fall then this is probably the reason why.
- Broiling – Broiling meats in cold ovens will cause them to dry out. Proper broiling sears the outside of the meat, which traps juices inside and keeps it tender and juicy. Broiling in a cold oven will start the cooking process too soon and the meat will cook instead of sear, then eventually cook at a very high temperature, which will dry it out.
- Roasting – Meats and vegetables that are roasted will get overcooked and/or dried out if cooking begins with preheating.
How long should I preheat?
Preheating in a toaster oven is very different from a traditional wall oven. The space inside traditional ovens is huge and preheating can 10 to 20 minutes. That’s a lot of energy being used to heat all that air!
The interior of toaster ovens, on the other hand, are very small. Even the largest models don’t have all that much air to heat up. The time needed to preheat these mini ovens will vary depending on the temperature you select, but it usually takes just a few minutes.
Curiosity got the better of me and I decided to do a little test in my kitchen to see how long both my oven and toaster oven took to preheat to 375° F. Want to guess which appliance won for speed? Yep, it was my trusty Breville BOV800XL, which took less than five minutes, compared to my oven which took over 11 minutes. The difference in time would be even more significant for higher temperatures.
Take a look at this video if you want to see my toaster oven’s preheating in action. It is, arguably, the most boring video in the world, and I found out that you can’t see anything on the digital display during recording (weird!), but you can hear the series of beeps that alert me to the fact that preheating is done. (If you listen closely you can also hear my cat Willow trying very hard to get my attention as I stood at the counter.) If you just want to hear the beep alert then skip ahead to the 4:46 time mark.
Do any models tell you when preheating is done?
Yes, many models, though not all, will let you know when they are done preheating. The most common alert method is a series of audible beeps heard when the heat has reached the set temperature. This is what my model does, the Breville BOV800XL.
How will I know if preheating is done if my toaster oven doesn’t have a preheating indicator?
The best thing to do if you buy a model that does not come with an indicator to tell you when preheating is done is to buy a small oven thermometer. You can place the thermometer inside and look at it through the glass door to know when the air inside has heated up to the desired cooking temperature.
There is an added benefit to using an oven thermometer. It will show you how accurately your toaster oven is at heating up to the selected temperature. If you find that your particular model consistently heats up either too high or too low then you can adjust the temperature for the best results during cooking.