How to tell if a piece of glassware is microwave safe

Microwaving is a common practice in modern-day households. The microwave has simplified the cooking and heating process, saving time and effort.

However, how do you tell if a piece of glassware is microwave safe?

In this article, we will look at different ways of telling a piece of glassware is microwave-safe.

Ways of Telling Glassware Is Microwave Safe

You need to be very careful about the glassware you put in a microwave to avoid cracking due to the difference types of glassware.

Here are some of the tips you need to tell if your glass is microwave-safe:

  1. Look for a label

Every item that is intended for the microwave always has a microwave-safe label.

Glass is no different, ensure before you place any glassware in the microwave you check for the microwave-safe label. 

Most microwave-safe glassware comes with a label that indicates it is safe to use in the microwave. 

You’ll find the label at the bottom of the glassware or on the packaging. Some labels may indicate the maximum heat the glassware can withstand.

If your glassware does not have a microwave-safe label, then do not microwave it to avoid any accidents.

  1. Check the glassware for cracks or chips. 

Even glassware that is labeled microwave-safe can still be unsafe. This happens mostly when the glassware has cracks, chips, or other damages.

Damaged glassware shatters when exposed to heat. It expands, so when the glass is cracked, during expansion it will shatter causing a potential risk of injury.

Inspect the glassware before microwaving, if it has any damage avoid microwaving it.

  1. Check the type of glassware.

Generally, most glassware is microwave-safe, but certain glass types are not.

Examples of microwave-safe glassware are:

  • Pyrex glassware
  • Glass-ceramics. 
  • Glass without metallic parts or paintings.
  • Glass that is not colored.

A natural glass that is made of sand, soda ash, and limestone can be used in the microwave.

Most glassware nowadays is synthetic such as tempered soda-lime and borosilicate glass.

This glassware withstands high temperatures.

However, compared to soda-lime glassware, borosilicate glass can withstand more heat.

  1. Conduct a test.

If the glassware has no symbols or you are unsure if the glassware is microwave-safe there is a test you can conduct,

The test has various steps, and they are:

  • Fill a microwave-safe glassware with water and place it in a microwave.
  • Place the glassware that is to be tested near the microwave-safe glassware.
  • Microwave the two glassware on maximum heat for one minute.
  • Remove them with a pot holder and place them on the countertop.
  • Carefully touch the dish with your fingers. If the dish is warm or hot it is not microwave

Related Post: Can you microwave cold glass?

Frequently Asked Questions

What makes glassware microwave-safe?

Microwave-safe glass is made from materials that can resist thermal shock.

Thermal shock occurs when there is a sudden temperature change, which causes the glass to shatter.

Borosilicate glass and soda-lime glass are microwave safe although borosilicate can withstand higher heat compared to its latter.

How can I tell if the glassware is microwave-safe? 

There are different ways to tell if the glassware is microwave-safe.

 Look for a microwave-safe label, check if the glass has any cracks or chips, ensure it does not have any metallic parts, and ensure the glass is not colored.

Can all types of glassware be used in the microwave?

No, not all types of glass can be used in the microwave.

Avoid using damaged glass, glass without a microwave-safe label, colored glassware, and glassware with metal parts.  

Is it safe to use recycled glassware in the microwave?

It depends on the type of glassware and how it was recycled. 

Glassware made from recycled glass contains impurities and other materials that make it unsafe for use in the microwave. 

Look for glassware made from recycled borosilicate glass which is specifically designed to be microwave safe.

Can I use glassware with metal designs in the microwave? 

No, avoid using any glassware with metal designs in the microwave. 

Metals cause sparks and arcs in the microwave, which damage the microwave and even cause a fire.

Can I microwave glassware that has a lid?

It depends on the lid. 

Glass lids are usually microwave-safe, but plastic or metal lids may not be. 

Check the label to ensure the lid is safe for use in the microwave.

Is it safe to use glassware previously used in the microwave? 

As long as the glassware is undamaged and labeled as microwave-safe, it should be safe to use in the microwave. 

However, avoid using glassware that has any visible damage or has been previously heated to high temperatures in the microwave, as this can weaken the glass and make it more prone to breaking.

Can I microwave cold glass?

Room temperature glass is microwavable, so long as the glass is tempered before microwaving.

Refrigerated glassware on the other hand needs to be warmed up before microwaving warming up avoids thermal shock so your glass does not shatter.   

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