Why Do Baking Sheets Bend in the Oven?

There is a lot more to baking than whipping up delicious treats in the oven.

Baking is a fun way to let out all your stress. However, baking isn’t the same as stovetop cooking. It requires precision, care, and constant monitoring.

Apart from temperature, getting high-quality baking cookware is also important. If you’re using baking sheets, you might’ve noticed, they tend to bend in the oven after a while.

There are many reasons for it and there are some things you can do to make sure it doesn’t happen.

Here, we’re going to discuss why baking sheets bend in the oven.

Why Do Baking Sheets Bend in the Oven?

Baking sheets bend in the oven because of high temperature.

Baking sheets and pans are made from multiple layers of metal. When the oven heats up, the metal reacts to the heat and begins to expand.

However, the metal doesn’t just expand in one direction or from one side. All the surfaces start to expand. This includes the four raised edges, the bottom of the pan, and the interior. The surfaces don’t expand at the same rate/speed.

For example, the bottom tends to expand faster and slightly more as compared to the edges. When this happens, there’s internal stress inside the metal. When one side expands more than the other, the baking sheet will bend or twist.

The chances of bending are higher if the baking sheet is too thin or made from poor-quality metal.

The stress from the opposing sides causes the sheet to twist or buckle. You will always be able to tell when the baking sheet is under stress. After all, when it’s exposed to high temperatures, it makes crackling or popping sounds.

Why Does Heat Cause Metals to Expand?

This is a simple lesson in physics. When metals are exposed to heat, they tend to expand and change their shape. It’s not just metals like steel. Many materials expand when they get hot. The reason for this is that heat is primarily a form of energy.

When this energy is applied to any type of matter – in this case, a metal sheet – it affects the atomic structure of the metal. The atoms that make up a metal sheet are already moving to some extent. These atoms are fairly stable as compared to those that makeup liquids or solids.

Nonetheless, they are moving in their place. When they’re exposed to heat, they move very quickly and violently. As the atoms continue to move, they tend to take up more space. With each atom now occupying a larger space, the metal structure begins to expand.

The longer the metal is exposed to heat, the more space the atoms will need. Eventually, they will cause the entire metal sheet to expand. The metal won’t become larger due to heat expansion. It will react by bending or losing its shape entirely.

A common solution to stop metals from expanding is to give them extra space. Sidewalks, for example, are constructed with grooves. This way, when they’re exposed to heat, the concrete has enough space to expand without cracking.

Since this is common in thinner metals, you need to take precautions. Most baking sheets will expand and warp, crack, or bend over time. However, because the surface is flatter and smaller, the problem is easier to remedy.

Here we are going to discuss some quick tips that will prevent your baking sheets from bending in the oven.

How to Stop Baking Sheets from Bending in the Oven

If your baking sheet has already become warped, you can’t do much.

However, if you bought a new one and want to ensure it doesn’t bend, here are some precautionary measures that you can take.

Allow the Baking Sheet to Cool Naturally After Baking

Metal sheets warp because of the sudden change in temperatures. This is especially true in the case of steel. You could be unknowingly trying to cool down the baking sheet.

For example, you might put it under cold tap water right after it’s been in the oven. Or, you might be pouring really cold ingredients when the sheet is already too hot.

If you have aluminum baking sheets, you won’t have to worry about warping. However, steel baking sheets are quite likely to bend or crack.

The best way to stop this from happening is to let the sheet cool naturally. When you’re done baking, place the baking sheet at room temperature. Be careful not to wash it immediately.

If you do wash it, the cool temperature will put stress on the baking sheet. Therefore, it’s always best to let the baking sheet reach room temperature. Once it has cooled down, you can wash it under the tap.

If the baking sheet is extremely hot, it’s best to put it back in the oven.

Switch the oven off and keep the sheet inside. Wait for the sheet to cool down inside the switched-off oven. Once it has cooled down, you can wash the baking sheet.

Use Thicker Metal Baking Sheets

Another great tip is to avoid thin metal sheets completely. Baking sheets are mostly used for delicate, thin cookies.

However, thin baking sheets can also cause the cookies to brown or burn easily. The best solution for this is to use baking sheets that are made from thicker metals.

A good option is a think aluminum baking sheet. Aluminum is extremely durable, affordable, and can withstand the oven heat. It has a stable structure that doesn’t warp or crack when exposed to high temperatures.

However, aluminum bakeware does have one problem. If it’s not coated with a protective layer, the metal can react with the food. For this reason, make sure to always line the baking sheet with parchment paper. This way, as the baking sheet heats up, it won’t even react with the food on it.

Aluminum baking sheets with rolled edges are the best choice. The ideal size you should be looking for is 13 by 18 inches.

This will offer a large surface area to bake cookies, bread, and pastries. The edges will protect the metal as it heats up in the oven.

Use Insulated Cookie Sheets

Insulated cookies sheets are a fairly new option. However, they’re certainly worth the investment. If you bake cookies often, these will be perfect for you. These sheets are made with a ½ inch lip and are quite affordable.

They are not too think or too thin. In fact, they will prevent your cookies from browning or burning too quickly. Insulated cookie sheets produce evenly baked cookies and pastries each time. The best part is that they don’t warp or bend easily.

However, insulated baking sheets require a slower time in the oven. If you’re following a recipe, make sure to modify it according to the baking sheet.

Cover the Baking Sheet with Layers

If you’re still going to use a steel baking sheet, here’s what you can do to prevent warping. Cover the pan entirely with parchment paper. This has a ton of benefits. Parchment paper prevents the food from sticking to the pan so there’s less cleaning.

Above all, it protects the surface of the baking sheet from burning or rapidly heating up. If you don’t have parchment paper, then don’t worry.

Just make sure to cover the baking sheet entirely with food. For example, if you’re baking cookies, line them all across the baking sheet. Make sure to leave only a few inches of space.

The food in itself can act as a source of insulation for the baking sheets. Silicon mat is another option you can use to protect your baking sheets. Also known as a Silpat, this mat will protect your baking sheet unlike anything else.

It’s nonstick, durable, and extremely easy to clean. It is smooth and can be easily lined over the baking sheet. The biggest advantage it offers is protecting the sheet from the heat. The mat encourages even and consistent distribution of heat.

This way, the baking surface heats up gradually and evenly. If you’re worried about reactivity, you can relax as silicone mats are food-safe.

They will never react to the food you’re baking. In fact, you won’t even need cooking oil or nonstick spray. They’re nonstick and perfectly sized for your baking sheet.

A Final Word

Baking can be extremely fun and easy when done the right way. However, looking after your bakeware is extremely important. If you’re going to invest in poor-quality baking sheets, they are quite likely to warp.

Choose baking sheets that are made from durable metals, preferably aluminum. This way, they won’t warp or bend out of shape when heated in the oven.

Above all, avoid any methods that attempt to rapidly cool down or heat up the baking sheets. Follow the tips above to look after your bakeware and prevent it from warping!

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