why are some dishes top rack only

Why are some dishes top rack only? You probably have seen the “Top Rack Only’ symbol on your glassware, dishes, and a wide variety of household items.

When it comes to figuring out what’s safe enough to be washed in a dishwasher, we usually have a hard time with it.

And because of this, we all have lost a few good cookware. 

This article is all about helping you figure out what is safe for your dishwasher. 

We would be answering a few questions like ‘what does top rack dishwasher safe mean?’

Let’s jump right into it

Some dishes are labeled ‘top rack safe’  to indicate that they should be washed in the top rack section of the dishwasher to avoid damage.

Knowing What Is Safe For Your Dishwasher

knowing what is safe

This might be quite hard for a few people to figure out, as not all manufacturers indicate on their products what is safe for a dishwasher and what is not.

This is wide because there isn’t a committee or organization that deliberates on dishwasher safety.

However, there are some good manufacturers of kitchen wares, glassware, and cookware out there that indicate on their products if it is safe for the dishwasher or not.

Their indications and symbols may differ but there are two main symbols or texts that are quite popular. 

They are;

  • Dishwasher Safe.
  • Dishwasher Safe: Top Rack Only.
Tip:  Again, this might not always come in the form of symbols on the dishes. You might come as a plain written text.

What Does It Mean For Your Kitchenware To Be Dishwasher Safe?

dishwasher safe

You probably have seen the symbols or the boldly written texts at the back of your dishes or kitchenware written, “Dishwasher Safe”.

This tells you that the manufacturers of that dish or kitchenware did treat the item to withstand any high temperature during the wash cycle.

A ‘Dishwasher Safe’ item can withstand whatever high-temperature level is used during washing as well as withstand whatever detergent is used when washing.

Basically, they are very durable and a suitable choice for your dishwasher.

If you are wondering how they are able to achieve this. Well, their methods vary depending on the material type. 

Regardless, here are a few examples to help with your understanding.

How Manufacturers Make Glass Dishwasher Safe

glass dishwasher safe

If you are not familiar with the process of making glass, this should give you an idea.

Most glass objects made, go through a process called annealing.

In this process, they are allowed to cool out so as to gain structure slowly evening out any stress that might have been gained during their production.

Annealed glass could also be seen as untreated glass.

To get treated glass, most manufacturers put the annealed glass through a process known as tempering.

This process is a chemical process, and it is aimed at making the glass stronger.

Another process could be used, which is called heat-strengthening.

It is a milder form of tempering and it makes the annealed glass twice as durable.

Note: Atempered glass can be 4 or 5 times more durable than an annealed glass.

How Manufacturers Make Ceramics Dishwasher Safe

ceramic dishwasher safe

For Ceramic items, a similar process to hardening glass is used.

They are first Annealed, after which glaze is then coated on the surface of the ceramic to keep it strong and protected.

Glaze comes in different types, and the type used on ceramic can affect the durability and strength of the item.

Tip: Contact the manufacturer, just to be extra sure of the ceramic type before placing it in a dishwasher.

How Manufacturers  Make Plastics Dishwasher Safe

For Plastics, whether or not you treat them doesn’t really matter.

What matters most is the quality of the plastic used. Plastic with a low melting point could be easily ruined by a dishwasher.

So, my recommendation is that you only place plastics in a dishwasher if you see that they are marked as top rack only.

In which case you place them in the top rack of the dishwasher.  That being said.

Why Are Some Dishes Top Rack Only?

some of dishes top rack only

We already discussed what Dishwasher Safe means.

However, you probably have seen some manufacturers label their items as “Dishwasher Safe: Top Rack Only”. 

What this tells you is quite simple.

Just as some kitchenware or cookware would require being treated to become completely dishwasher safe.

Some kitchenware or cookware, despite being treated, cannot withstand the high temperature that is emitted from the dishwashing machine.

They would require you to place them in the top rack of the dishwasher to avoid getting damaged or ruined.

The bottom part of the dishwashing machine is where the heating element is usually located.

So keeping your cookware, kitchenware or other items in there can lead to it melting or even losing their color by the end of the washing cycle.

Tip: It helps to reduce the timer or duration in which your cookware or kitchenware is being washed in the dishwashing machine.

Plastics With The Top Rack Only Label

plastics with top rack label

As we have already established earlier, plastics are most often recommended as top rack items in a dishwashing machine.

But you might be wondering “ plastic in dishwasher top rack why?

Well, for plastic to be safe for dishwashers, it would have to go through some level of treatment.

However, despite being treated, you can’t guarantee a plastic as “Disposable Safe”, so it is usually wise to keep them in the upper rack just to be safe.

Types Of Plastics That are Dishwasher Safe

types of plastic

 When it comes to selecting Dishwasher Safe plastics, there usually are two categories of plastics that come to mind.

These are the Cutlery and Tableware, as well as Reusable plastics.

Cutlery and Tableware

Some good examples of ‘Dishwasher Safe’ labeled plastics are chopping boards, baby bottles, outdoor plates, acrylic glasses, and cutlery.

These items are usually made with plastics that have a high melting point, so they would survive some high temperatures.

Reusable Plastics

reusable plastics

Plastic kitchenware or cookware that is marked as reusable could be safely washed in the dishwashing mashing.

Again, it is strongly recommended that you wash them only in the top section of the dishwashing machine. 

And avoid exposing them to long clean cycles in the dishwasher.

Tip: When washing some of these items, do ensure they are washed in low temperatures so as to protect them from damage to high or excess heat.

How About Plastics That Are Disposable?

disposable plastics

Disposable plastics are totally unsafe for the dishwashing machine.

They have very low melting points, so regardless of whether they are placed in the top section(top rack) or not, they would end up warping or melting.

In addition to that, disposable plastics and silicone have something called Bisphenol A, or BPA alternatives, they could be very harmful to the body when exposed to high temperatures.

So, having your food served in disposable plastics might not be such a good idea.

Frequently Asked Questions (FAQs)

questions about dishes

Can Wood Be Placed In A Dishwashing Machine?

It is recommended that you wash all wooden kitchenware or cookware by hand.

This is because some dishwashing machines could emit very high heat that could be harmful to wooden items.

They could cause the wooden items to split, swell or even warp.

Should Knives Be Placed In A Dishwashing Machine?

Knives that are sharp might not be great objects to place in a dishwashing machine.

This is because they could easily become dull or nicked.  Also, the sharp knives could equally damage the racks of the dishwashing machine.


Hopefully, the information given in this article should help you with determining what is right for your dishwasher and also in answering the question “Why are some dishes top rack only?”.

Using your dishwasher or dishwashing machine shouldn’t always spell doom for your kitchen utensils or cookware.

Knowing what is a perfect item for your dishwasher is a good start towards protecting both your cookware and your dishwasher.

With that being said, that’s all we have for you in this article, do ensure you check out our previous articles as you might learn something new.

For now, eat well, drink a lot of water and remember to stay good.