A dishwasher is an electrical machine and it has some limitations.
You can’t have it all and that is why a dishwasher cannot wash every utensil and cookware in your kitchen.
Even if some of our favorite mugs can be washed in a dishwasher, there are still some which cannot.
The main reason behind unsafe dishwasher mugs is their engineering.
For example, insulated mugs have a sealed inner and outer layer with air in between or vacuum, or some other insulator.
While cleaning these mugs in a dishwasher, water or moisture may penetrate into that space.
The pressure and heat of a dishwasher can break this seal and ruin the mug.
Low quality plastic mugs may melt inside the dishwasher.
Other non-insulated mugs may have some chemical coating, paint, or design which can also get ruined in a dishwasher at high temperature and moving water.
That’s why their label says ‘not dishwasher-safe’. Let’s understand how a dishwasher-safe mug is manufactured to know why it can tolerate the heat and pressure inside the machine.
Why are Some Mugs Not Dishwasher Safe and Why Some Are?
‘Dishwasher safe’ is a phrase that you can easily find in your kitchen written at the bottom of some plates, mugs, cookware, and other things.
It is like a simple notice or indication from a manufacturer that the particular item is made up of safe components or made up from a safe manufacturing process which makes this item safe to wash in a dishwasher.
Each company producing kitchenware has its own system and standards and according to that, they label their products with information about safety and the precautions of using and washing them.
Clearly, mugs that are dishwasher-safe has some unique engineering or definite manufacturing process to prevent the damages which can cause by a dishwasher.
Materials like aluminum, stainless steel, glass (tempered and borosilicate), stoneware, ceramic, silver, crystal, etc are dishwasher-friendly.
Hence, mugs made of these materials are able to withstand high heat and pressure inside the dishwasher. For the same reason, these mugs are more durable and impact-resistant.
Not all glass-made mugs are dishwasher-safe. Mainly the limescale glasses are not. Also, some high-end plastics are able to go into the dishwasher, whereas the rest cannot. Again it depends on the manufacturing material and process.
Some mugs are made with mixed materials where one is dishwasher-safe and the other is not resulting in a completely dishwasher-unsafe mug.
How Do You Know If A Mug Is Dishwasher Safe Or Not?
The easiest way to find whether a mug or any cookware is dishwasher safe or not is to look for the symbol or the actual phrase of it on the dish. Many brands use the term directly or you can check for the symbol as well.
It will be like a plate or a glass with some water droplets above it. After some experience, you will get an idea of what can’t go in a dishwasher and what can. But for general information utensils that have some wood, nonstick surfaces, glazed ceramics, and low melting plastics should be avoided in a dishwasher.
What If You Wash a Mug Which Is Not Dishwasher-Safe In A Dishwasher?
If your utensil has a symbol and/or clearly stated in the manual or any image as dishwasher-unsafe then you must avoid it. But if you are not aware of it and mistakenly put your mugs in a dishwasher then a few things can happen which you should be aware of.
Mugs that are not dishwasher safe can get damaged in a dishwasher completely. Insulator cups may lose their insulation. Moisture, water, or detergent can break the surface coating or design of your mug. High pressure can break your glass mug.
If you are washing a plastic mug then hot water and a high temperature of the dishwasher can even melt that mug as well. Overall, the sight will not be pretty.
Which type of mugs cannot be washed in a dishwasher?
If you are using insulated mugs whether plastic or plastic insulated or metal ones they all are not suitable to wash in a dishwasher. Insulated mugs generally have some liquid or air in between the layers which can easily get ruined in a dishwasher.
If you are using copper mugs then also it is advisable to wash them by hand. As copper can also get damaged in a dishwasher by hot water and heavy chemicals. You should also avoid washing mugs with adhesive labels. Anodized aluminum also gets scratched in a dishwasher.
Important Points To Note While Buying a Mug:
Some mugs are not dishwasher safe because of their engineering. As, inside the dishwasher, the mugs go under some extensive cleaning cycles where higher water pressure and heat play an important role, the quality of the mug matters a lot.
The poor durability of a material, the delicate designs, and high-heat intolerant chemical coatings of mugs make them dishwasher-unsafe. Handwashing them with light dish liquid is highly recommended. Before buying a mug always make sure it is dishwasher safe. Not for the sake of cleaning but also for its longevity. Dishwasher-safe mugs are more impact-resistant. In the case of insulated mugs, check if the lid is dishwasher-safe or not.