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Microwaves

Why Did My Microwave Come With A Metal Rack? (Explained!)

Antonio Forde
Updated: March 30, 2024
6 min read

Metal and microwaves do not mix, so you have been told, but do you know that some oven models come with a center metal rack?

What is the shelf for? Is it safe to use?

Here’s Why Microwaves Come With a Metal Rack:

Microwaves come with metal racks to cook multiple food items at once. These racks are specifically designed for the appliance they come in, so they are safe to use. With the metal racks inside the oven, you have more space to heat up two or more containers at the same time.

What Is the Metal Rack Used For?

That metal rack inside your new oven is safe to use for cooking several dishes simultaneously. 

When used correctly, it can be a helpful tool in your culinary endeavor.

Metals racks are great for two-level cooking since it opens up more space inside the oven. You can place the food item on the spinning tray and another on the rack, allowing you to cook two or more meals together.

Since the racks allow for better energy wave and heat circulation, it is also excellent for microwave defrosting.

The additional wave flows moving over, under, and the sides of the food or container aid in thawing and cooking.

You can also use microwaves with metal racks for convection oven cooking. 

Most microwaves now have features of convection ovens. 

Combining the heating capacity of conventional ovens with the speed of microwave cooking, these ovens are superb in baking, roasting, and grilling.

Food is heated up quickly and uniformly thanks to the efficient circulation of hot air through the oven cavity.

Since heat is distributed equally, you can avoid cold spots that keep portions of food uncooked.

If you are baking using the metal rack, you will find that butter melts and releases steam quickly, resulting in flakier baked goodies.

It also takes less time to roast and grill meat since the heat causes fats to render fast and the skin to crisp.

Since microwave convection oven temperature and timer differ from conventional ovens, you should keep a careful eye on your dishes until you are familiar with heat and cooking time.

Metal racks allow for even cooking and defrosting because it heats up the dish from all angles, but you can still afford to be extra cautious.

Since they are fixed, unlike the turntable at the oven bottom, you probably need to turn or rotate food halfway while cooking or reheating to get rid of cold spots.

Microwaves with turntable functions need movement for the food to cook uniformly. 

Once your appliance starts running, it produces microwaves that bounce off the oven walls. These waves penetrate your food, heat up the molecules within, and cook it from the inside out.

The spinning tray ensures that your food gets to absorb the heat coming from all directions.

With metal racks, the food stays stationary. Stirring helps keep the waves circulating, cooking every dish segment.

Is a Metal Rack in a Microwave Safe?

Metal racks in the microwave oven are definitely safe, but there is a warning on improper installation.

You should make sure that the rack is fitted with plastic hooks or rubber clips so it will not come in contact with the sides of the microwave.

The metal-to-metal contact may lead to sparks and other issues if placed incorrectly. Arcing and warping may occur if the rack touches the oven walls, ceiling, or base.

Racks are designed to slide right into place on these hooks, so you should get the setup right away. 

You should never attempt to use any other rack beside the one furnished with your microwave. 

These racks are purposely designed for those appliances, so using a different one can be disastrous.

When cooking or reheating using the metal rack, you must consider the following suggestions.

You should only use microwave-safe dishes. Even if you are just utilizing the rack, standard microwave safety precautions must be followed.

This means avoiding using metal cookware and utensils. Browning dishes are also a no-no. 

A browning dish is typically made of pyro ceramic material with embedded metals. Cooking using this may cause damage to the rack. 

A broken rack is a potential hazard. It may cause sparking, which then leads to fire.

You should also avoid food containers on the rack to touch the oven tops or sides. Microwave-safe dinnerware, like ceramic, glass, and plastic containers labeled for microwave oven use.

Cooking food directly on the rack should also be avoided.

If you are going to pop popcorns, never use the rack. When the popcorn bag expands, it could push the rack off its hooks.

The metal rack coming in contact with any metal part of the microwave may lead to sparking and other serious issues.

Just like when you avoid running a regular microwave while it is empty, you must also refrain from operating the appliance with the metal rack without food.

This may damage the magnetron. The magnetron is the device responsible for releasing the electromagnetic waves that cook or heat up your food.

If your appliance’s magnetron breaks, you will need to repair or replace it.

If you do not need the extra space, it is best to remove the rack. Instead, you should store it on a shelf or your cabinet.

Manufacturers caution against storing racks inside the microwave when not in use.

Does Metal Spark in the Microwave?

Generally, yes. Metals that come in contact with the microwave oven’s internal surfaces cause sparking. The same happens when a metal inside is pointy and with edges, like forks and aluminum foils.

Even some stoneware with traces of metals embedded can throw sparks when zapped.

Microwave ovens contain a magnetron, a metal box that produces electrons. These electrons zip around the chamber filled with electric and magnetic fields, repelling and forcing them to go in circles until it touches the special cavities inside.

The electric energy from the electrons causes the cavities to resonate at a particular frequency and produce electromagnetic waves. 

These waves bounce back and forth in the oven walls and are absorbed by whatever food you put inside. 

The radiation produced by the microwave targets water molecules, making them vibrate then turn into heat. This heat warms up your meal. 

If you have metal inside the oven, the heat that the radiation generates can warm it up extremely rapidly. Once the metal becomes too hot, it could start to burn.

There is a reason why manufacturers warn against placing metals with sharp edges and dead-ends inside your oven.

While the electrons are naturally repelled from areas with too much charge, they congregate in areas with air spaces, like the fork tines or aluminum foil kinks.

Once this happens, the electrons skip and create a spark, changing the air molecules into plasma.

The sparks should not cause fire, but if they hot something flammable inside the oven, they could ignite.

However, there are instances where metals in the microwave are not hazardous. 

Thick metals heat up slowly. They are unlikely to create sparks if they do not have sharp edges.

One example is the metal rack that comes with your microwave oven. 

Metals racks are specially designed to avoid sparking situations. Since they are held in place with plastic hooks, they do not come in contact with the oven walls at any point.

They also do not have sharp edges that can trigger sparking.

If there is sparking in the microwave while using the rack, you probably did not install the rack properly. Immediately stop the appliance and check if the rack somehow touches the oven interior.

If the rack is mounted correctly and still sparking, there may be a mechanical issue. You should call the appliance manufacturer for help. Do not try to fix the appliance on your own.

Using a metal rack other than the original one may also lead to additional issues. Microwaves are meant to work with the specific rack they came with. 

Sources:

Reader’s Digest

US FDA

WIRED

Written by
Antonio Forde
I'm the head-writer @ Ask The Home Geek (or, in plain English, I'm the guy writing & editing the majority of the content here). Current learning project: Korean.
Have any questions? Write us a message.
Antonio Forde
I'm the head-writer @ Ask The Home Geek (or, in plain English, I'm the guy writing & editing the majority of the content here). Current learning project: Korean.