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Your oven is one of the most important pieces of equipment in your kitchen. With luck, yours is spacious, sturdy and reliable. Regardless, we cook with the oven we have, not the oven we want, so it’s in our best interest as cooks to get to know our oven very well, with all of its strengths, weaknesses, and quirks.

Oven basics:  heating elements, racks, and dish sizes

We’re going to limit this conversation to electric ovens, which comprise the vast majority of ovens installed in home kitchens. Most electric ovens have two heating elements: one on the top of the “box”, and one on the bottom. “Bake” settings on the oven typically use only the bottom one; “broil” settings use the top one.  Some higher-end ovens have a special “pre-heat” function that uses both top and bottom heating elements simultaneously to heat up a cold oven faster. Newer digital ovens often have an indicator on the front panel that tell you which of the two elements are in use. Older ovens leave the heating elements exposed inside the box; newer ovens often hide them just above and below the top and bottom walls (which makes cleaning your oven much easier).

Three things get heated in an oven: the air trapped inside, the walls, and the food (including the dish). Unless your oven is set to a high broil, your oven is an “indirect heating” system: the heating elements heat the air, and then the air transfers the heat on to the food.

Convection ovens are a twist on regular ovens: they use an extra fan to more aggressively circulate the air inside the oven. Without the fan, we rely on “thermal convection” to move the heat from the elements to the food; hot air rises – which is why the “bake” setting uses the lower heating element. But with the fan the oven can circulate hot air more regularly throughout the entire oven.  This is an important point: all ovens have “hot spots” and “cold spots” depending on the size, shape, and quality of the heating elements, and how efficiently air moves around inside the oven (especially when it has baking dishes inside of it, which often restricts air flow). Convection ovens to some extent compensate for the natural hot and cold spots by circulating the air better. But it’s not accurate to think of a convection oven as simply a higher-quality regular oven: it’s an oven that transfers more heat to the food and therefore will cook food faster. If you take a recipe designed for a standard oven’s “bake” setting and cook it on the convection setting instead, it will almost always cook faster; that may be a good thing, but make sure you’re checking for doneness earlier or you will overcook your food.

As an aside, an air fryer – all the rage these days – is a small convection oven. If your oven has a convection setting, you essentially already have an air fryer. That doesn’t mean you shouldn’t buy a separate air fryer if you want to be using it while simultaneously cooking something else in your oven. But if you’re thinking about buying an air fryer for occasional use, you might want to consider whether you can use your existing convection oven to accomplish the same thing.

Most ovens have two or three racks that can be removed entirely or repositioned at different heights in the oven to control how close they are to the top and bottom heating elements – and to each other, to ensure the air inside the oven can circulate.  Many recipes will suggest repositioning a rack at a particular level. Also if you’re cooking something tall, such as a roast, you might need to move the rack down to ensure that you have enough available height. It’s easiest to figure out all of this before you start pre-heating your oven – though every cook I know, including myself, has made the mistake of forgetting to check rack height first and having to manhandle racks to a different height (or remove them altogether) in a hot oven using an awkward pair of oven mitts.

Baking dishes

There is a standard size for shallow baking sheets, based upon the ones used in commercial ovens. A “full sheet pan” measures 18 inches by 26 inches; it fits into a commercial oven, but it almost never fits into a home kitchen oven. Don’t buy full sheet pans unless you know they will fit in your oven and you have a specific purpose for a sheet pan that large.  Instead, buy “half sheet” pans, which are 18×13 inches, and “quarter sheet” pans, 9.5×13 inches. Both will fit into a standard home kitchen oven and allow enough airflow around them to ensure even cooking. These will be the multi-purpose workhorses of your kitchen. The nice thing about the standardized sizes is that all of the things that you want to use with them – parchment paper, wax paper, aluminum foil, etc. all can be bought in the right sizes to fit them. I keep a stack of sheets of parchment paper, pre-cut to 18×13, in a drawer in my kitchen, so I can always grab one and throw it in a half-sheet pan – or fold it in half and put it in a quarter-sheet pan.

For deeper dishes, the standards are measured by the size of the interior area (they often have flanges or handles at the ends so they can be picked up). The two standard sizes are 8×8 inches, and 9×13 inches; both are 2 inches deep. There are also standard bread pans – again measured by the interior size – 8.5×4.5 inches, and 3 inches deep.

You will find bakeware in all shapes and sizes, in stores and online (and in your mom’s kitchen cabinets); if you have a specific need of them, by all means pick them up. But keep in mind that most recipes are designed for standard-size bakeware, so make sure you have them too!

We need to talk about your oven’s thermostat

Here’s a hard but important truth:  the thermostat built into your oven is notoriously unreliable and almost certainly wrong – by as much as 20 to 30 degrees in either direction. This is true for both older ovens and brand-new ones. Because as cooks we care about things like the Maillard reaction, that happen at around 350 degrees, it’s very important to know what temperature the oven is REALLY at – not what the oven tells us it is. Changing the temperature of a recipe by 20 degrees can make a big difference, not only in how long an item takes to cook, but how thoroughly it cooks, how it sets in the oven, and how much it browns (or burns). On the flip side, taking firm and precise control of the temperature of your oven, more than anything else, can make your cooking very reliable: you can repeat the same dish over and over, and it will come out consistently the same.

This is one of the most important pieces of advice I give, and it’s not optional: go buy a reliable oven thermometer, and keep it in your oven. In the best case, over time you’ll learn how far off your oven thermostat is, and in newer ovens you can even re-calibrate the oven thermostat up or down by up to 20 degrees to make it more accurate. In the frequent case, you’ll learn how far off your thermostat is and adjust how you set your oven accordingly. In the worst case, you’ll learn to simply ignore the oven thermostat and go by the thermometer you bought.

I know you’re probably skeptical of this, but you’ll be convinced the first time you try it: pre-heat your oven to 350, and then see what the oven thermometer says the temperature REALLY is in your oven.

There are good oven thermometers and bad ones, and this is a case where it’s absolutely worth a little bit of extra money to get a good one, because you will be using it all the time. Digital thermometers and mercury-based thermometers are good: they are highly accurate and will last a long time. The classic dial-based ones, which are based on a metal coil that expands and contracts as it heats and cools, are terrible. The more heating-cooling cycles they go through, and the higher the heat, the less accurate they become over time. They are certainly cheaper than a digital or mercury-based thermometer, but they will be useless after about six months of regular use.

Pre-heating your oven

Here’s the other thing to know about your oven: when it tells you that it’s preheated to 350 degrees (or whatever temperature you set it to), it’s not at that temperature. It’s really telling you that the air immediately surrounding the thermostat – in whichever back corner of the oven it’s hiding – is that temperature. The rest of the air in the oven is a range of temperatures. More importantly, the walls of your oven are still significantly cooler. We care about that because when we open the door to insert something into the oven, all that warm air rushes out and the oven temperature drops instantly – and it will take several minutes to fully heat up again.

Here’s the trick to pre-heating your oven: after it beeps to tell you that it thinks it’s pre-heated, leave it for another ten minutes. That gives the internal air time to circulate, and the oven walls time time to come up to the preheat mark as well. Now, when you open the door, you will still lose some hot air, but the heat trapped in the walls will help to ensure that the oven and air come back up to the right temperature quickly.

As cooks, we’re looking for consistency and predictability: we want to remove as many variables as possible, so that what we think will happen in our kitchen is what actually happens. Knowing what temperature your oven is at, and fully pre-heating your oven, are critical steps in getting control over your cooking. Fortunately, there is no skill involved with this: it’s just knowledge, and now you have that knowledge you’ll be a better cook for it.

Hot spots and cold spots

All ovens heat somewhat unevenly, because the heating elements and the air flow don’t hit every part of the oven equally. Hot spots and cold spots are the norm, and learning where they are in you oven will help you to get your creations to fully cook (but neither under-cook nor overcook in places). Remember to think in three dimensions: hot and cold spots can be towards the front or back, in the center or to the sides, and near the top, center or bottom of the oven. Also, putting food and pans in the oven will change — if not constrict — the air flow, and can create a different pattern of hot and cold spots., especially if you’re using large pans on multiple oven racks.

An easy way to learn where the hot and cold spots are in your oven is to bake something that fills up a whole half-sheet pan, such as granola or a tray of biscuits. As they bake and brown, you can literally see the difference in cooking in various spots inside your oven. Ideally you will want to repeat this with a tray on a rack at different heights (baking multiple trays simultaneously can skew the results, though it’s interesting to know how much the heating pattern changes when the oven is full).

We can’t get rid of hot and cold spots, but we can manage them. First, make sure that you have fully pre-heated your oven (about ten minutes after it beeps to tell you that it’s pre-heated); this will ensure that the walls are warm also and help to more evenly distribute heat.

Second, rotate your pan halfway through its baking time, so that all parts get some time in front and some in back (which is where hot and cols spots often exist).

Third, if you are using more than one rack simultaneously, swap pans between the racks halfway through.

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