Pyrex dishes and lids can be used safely in the microwave. Always make sure at least one corner of the lid is lifted so that steam can escape. Pyrex dishes are made from tough tempered glass which can withstand microwave temperatures and glass, plastic or silicone lids are heat proof.
This article will explore all you need to know about using Pyrex in the microwave including how to heat your food safely and how to protect your Pyrex.
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How to know that your Pyrex is microwave safe
Pyrex will be marked “Microwave safe” with written words on the lid and base. While it can be tricky to see this written on the base as it is imprinted on the glass, you should be able to read the inside of the lid easily. Both the lids and base of Pyrex dishes are microwave safe.
Avoid microwaving frozen or very cold glass as you could risk thermal shock and the glass could shatter. The toughened glass that Pyrex is made from is strong and able to withstand the microwaving process.
Microwaving cold Pyrex
You can microwave Pyrex containers that are at fridge temperatures. I have always moved my small Pyrex lunch containers straight from the fridge to the microwave without any problem. I will simply lift up the whole lid or just one corner to let the stem out.
Pyrex will microwave well in short bursts. Start with 2 minutes and if your lunch needs more heat, stir and microwave for 1 more minute at a time until heated through. I recently bought a new microwave that is much more powerful than my old one. I will microwave small dishes for only 2-3 minutes in total from the fridge and the food is steaming and heated through.
Microwaving frozen Pyrex
It is best not to microwave Pyrex straight from the freezer. There is a risk that the rapid change in heat will crack the glass. If you have frozen food in Pyrex, take it out of the freezer 24 hours before you want to eat it and put it in the fridge.
Once the food and the Pyrex container have reached fridge temperature around 1-4 degrees Celsius or below 40 degrees Fahrenheit you can microwave it safely. Always lift the corner of the lid to let steam escape.
Using Pyrex in the microwave
Pyrex containers come in a range of sizes and the new ones are made from toughened glass which works great in the microwave. If you want to reheat food from a large Pyrex container it can be best to move a small amount into another microwave safe bowl or container.
Most large Pyrex containers will not fit in a microwave and will take too long to heat up evenly. For meals like lasagna, take out a single portion and microwave it separately. You could use a smaller Pyrex container or a ceramic dish with a cover to help to keep your microwave clean.
How to safely microwave food in Pyrex
There are a few easy guidelines to follow to safely microwave food in Pyrex containers. Here are my easy guide to success.
1. Choose a small container
It is best to microwave food in individual sized Pyrex containers because they will heat through quickly and thoroughly. Start with 2-3 minutes in the microwave and mix the food. Heat the food until it is steaming hot to make sure it is safe to eat. Stir the food after you have finished microwaving to evenly distribute the heat.
2. Let the Pyrex container defrost in the fridge first
Allow Pyrex containers that have been frozen to come to fridge temperature before microwaving. Move the container from the freezer to the fridge 12-24 hours before you want to microwave it.
Small single use containers will only usually take around 12 hours to get to fridge temperatures whole frozen lasagnas need closer to 24 hours to come up to fridge temperature from frozen. For larger containers it is always best to microwave small amounts at a time to heat it quickly and thoroughly.
Never microwave a frozen Pyrex container as it will put the container under a large amount of stress and can cause thermal shock and breakage.
3. Always lift the lid
It is important when microwaving food in Pyrex containers is to make sure at least 1 corner of the lid is lifted. Whether your Pyrex container has a plastic or silicone lid it should always have room for the steam to escape.
Glass Pyrex lids can also be microwaved but move it slightly across so there is gap for steam. You could place a piece of paper towel on top of the container to catch any extra splashes.
4. Avoid microwaving damaged glass containers
Avoid putting chipped, broken or vintage Pyrex containers in the microwave. Any cracks or chips will be a weak point and could break when it is heated in the microwave.
Replace any broken or damage glass containers with new to keep you and your food safe.
Using Pyrex in the Microwave | Summary
Pyrex containers can be microwaved and you can usually find that written on the bottom of the glass container and inside the lid. Never microwave a frozen Pyrex container, instead always place it in the fridge to defrost first.
Microwave Pyrex in short bursts and stir the food regularly. Microwaving the food for 2 minutes at a time will help to heat it thoroughly. Always lift one corner of the lid to let steam escape.