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Can You Put Glass in The Microwave?

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Glass containers are convenient used for storing, freezing and reheating food in many households. It is advantageous to keep any food in glass compared to other materials like plastic. 

When it comes to microwaving, you need to confirm whether the glass you are using is microwave safe. 

Can you put glass in the microwave? Not all glassware is microwave-safe. Check the bottom of the container to look for microwave-safe symbol, otherwise simply run a test by filling up the glass with water and microwave on high heat for one minute.

If the glass is heat resistant, the water will become hot and the glass will remain cold. However, if the glass become hot and water inside is cold, then the glassware is not capable of microwave use.

Unsafe glassware may cause an explosion in the microwave. Decorative cups are generally not safe for microwave, but glass cookware without silver or gold rims are microwave safe.

Always check the material of the glass keenly when purchasing glass containers. Choose the material that suits your lifestyle, especially if you intend on microwaving glass.

In this article, you will learn what types of glass can be put in the microwave and how to determine if your glassware is microwave safe. Continue reading for answers to frequently asked questions about putting glass in the microwave and inherent dangers associated with the action.

Can Glass Go in The Microwave

If you have jars, bottle and various glass containers, you must be wondering whether to put them in the microwave or not. 

Some glass is microwave safe, which means you can use them to reheat or cook food in the microwave. Unfortunately, not all glass containers are microwave safe, and some break when subjected to high temperatures.

Microwave-safe glassware, like Pyrex, have high heat resistance up to 1000 degree Celsius and a stable structure; this makes it suitable for microwave use. Furthermore, use it repeatedly due to its excellent penetrability and stable chemical properties, this type of glass is also known for acid-resistant and durable. 

Interestingly, you can apply various methods to check if your glass container is microwave safe; try the following:

Look for the safe label

Review the container and turn it over to check for the safety label. In most cases, the microwave-safe title is written at the bottom of the container if the glass is compatible. 

A sign stating “safe for microwave use” or “microwave-safe” are clear indicators. If your glass has this label, place it inside the microwave directly. 

If it doesn’t have the safety label, try the second option. Sometimes manufactures don’t go through the FDA approval process to properly label the product.

No label doesn’t guarantee that the material unusable in the microwave. Give it a quick test to check how it preforms.

Carryout A Run Test

Perform a simple test run if you are not sure if glass bowl is microwave-safe or not.

  1. Turn on the microwave and switch to the highest power setting.
  2. After turning the heat on, take a microwave-safe cup and add water to three-quarters level. Then put the cup of water inside the microwave.
  3. Avoid pouring water into the glass container in question. If your glass is small, put the cup of water beside it. In a situation where your glass container is oversized, put the cup of water on it without spilling.
  4. After putting the glass container and cup of water in the microwave, set the timer for one minute.
  5. When a minute is over, check if the water remains cold and the glass container is hot. In this case, your glass container is not safe for microwave use. On the contrary, if the water is hot and the glass container is cold, your container is safe for microwave use. However, the glass container may be warm at the center if you placed the cup on it.

To avoid possible risks, it is essential to know the status of your glassware before putting it in the microwave. Always perform a quick test of your glass container by following these tips if you are not sure of its safety.

What Happens If You Put Glass in The Microwave?

It is essential to distinguish what type of glass it is before putting it in the microwave. If you have heat resistance glass, you can put it in the oven while following safety measures.

However, toughened and ordinary glass containers can only be used for a short heating period in the microwave, at the utmost a total of 3 minutes. Under high temperature, the glass can explode. 

Delicate glass is likely to crack when exposed to excess heat. Crystal and curved glass products are likely to burst when heating oily food because of the uneven thickness of materials.

Furthermore, fat and sugar rich foods heat at much high temperatures than water based foods. Cautiously microwave foods with a significantly high fat and sugar content.

Why Does Glass Break in Microwave?

The type of glass that is unsafe for the microwave typically has tiny air bubbles that expand when heating. When these bubbles continue rising in temperature, the glass will finally break since the increased heat causes the glass material to stretch unevenly. 

If the stresses are strong enough, they cause the glass to break. Decoration and embellishments are another concern for structural integrity of glassware.

Some glass containers are trimmed with metal making them unsafe for microwave usage. When heating in the microwave, the metal spark shattering the glass.

A glass with a safety label can break when put in the microwave if it has tiny cracks or chips. Uneven heating can also cause a breakage of your glassware. 

Check the condition of the glassware before putting it in the microwave. Avoid microwaving glass with silver or gold rims as the metal may react with the electromagnetic waves.

Things to Know About Microwaving Glass

Glass with a microwave-safe label is best for reheating or cooking food in the kitchen appliance. Even though some don’t have the safety logo, they are likely to be safe because glass doesn’t leach chemicals into your food like microwaving plastic does. 

Without the safety label, it means they are of poor quality and delicate, but this doesn’t mean they will explode when microwaved. Unfortunately, it might crack when you remove it from the oven and the thermodynamic transition between hot and cold occurs too quick. 

Metal sparks from the microwave destroy fragile glasses. Though the glassware won’t catch fire, it may shatter from the surge of energy.

Avoid heating cheap glass as they are not heat resistant and break under high temperature. Ordinary glass can break by only putting hot food or drink in it, otherwise using glass is far better than using plastic, styrofoam, or cardboard to heat your food. 

Don’t heat frozen things in the microwave using glass. If you have to microwave cold glass, then do it under low heat while stirring the food to ensure the heat is spread gradually throughout the dish. 

In addition, if the pressure of the hottest spot weakens the tension of cold spots along with the glass, it will cause it to shatter. 

Is it safe to put glass in microwave

Putting Glass in Microwave: Final Thoughts

From cup to container, glass is an essential tool in the kitchen to store and revive food in the microwave. Not all glass can be microwaved, so look for microwave-safe symbol at the bottom of each container to find out.

When uncertain whether it is microwave-safe or not, simply test it out by placing two-thirds of water in the cup and place in the microwave for high setting. Evaluate whether the water is hot or cup is hot to determine if the glass container is microwave-safe.

Always test the dish before actually reheating your food. By doing so, you will save time and potential safety hazard with this easy test.

Glass consists of tiny bubbles and when the heat is forced, the high temperature expands these air pockets that may cause the glass to shatter into pieces. 

The most amount of time that glass can handle in the microwave is about 3 minutes. Ensure to rotate and give enough time between each interval, even when using microwave-safe glassware.

Glass with a safety label can still break under high temperature or rapid thermal dynamic transitions between hot and cold temperatures.  Avoid heating when your glass container is frozen or extremely cold to protect yourself from an explosion. 

Glass is typically safer when heating food in the microwave than paper and  plastic based materials because glass is stable and doesn’t leach chemicals into your food. 

It is essential to check whether your glassware is safe for microwave use to avoid potential explosion risks. Check the material closely before deciding if it can be put into the microwave, safety first.

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