Can you microwave a mason jar? It seems convenient, but is it safe? Whether you’re heating up yesterday’s dinner or preparing something new, understanding the right way to use mason jars in the microwave can save you from a kitchen disaster. Here’s what you need to know to keep things safe and simple.
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Why Would Anyone Want to Microwave a Mason Jar?
Mason jars are incredibly convenient for microwaving food and here’s why:
- Convenience – Mason jars are ideal for storing, freezing, and reheating leftovers or prepared meals. Microwaving food in the same mason jar you stored it in saves time and dirty dishes. Just take the jar out of the fridge or freezer, pop it in the microwave, and your meal is ready in minutes.
Preservation of food – Mason jars are designed for canning and preserving, so they can withstand microwave heat without leaching chemicals. This makes them safer and healthier for reheating food than plastic containers. Microwaving in the jar also helps keep food fresh and retain nutrients longer than transferring to a new dish.
Are Mason Jars Microwave Safe?
There are two main safety concerns to keep in mind when it comes to microwaving mason jars.
Risk of Shattering
Heating up a mason jar can cause it to crack or shatter, sending broken glass and hot food flying. This is because mason jars are made from heat-sensitive materials like glass, ceramics, or porcelain.
When you microwave these materials, the heat builds up very quickly and unevenly. This rapid temperature change causes the jar to expand at different rates, resulting in stress fractures. Any small nick, scratch, or imperfection in the glass can lead it to crack under this stress.
Shattering is more likely to occur with cheap, thinner glass or vintage/antique jars. Newer tempered jars are less prone to breaking. Still, microwaving any glass jar poses a risk of shattering.
Superheating Dangers
Another safety issue is the risk of superheating and boilover. This happens when a liquid is heated past its boiling point, but lacks bubbles to trigger full boiling. Once disturbed, the liquid can erupt out of the container.
Mason jars are prone to superheating because their smooth glass surfaces lack nucleation sites for bubbles to form. Using a mason jar with microwave-safe modifications like vented lids can help avoid this. Regardless, microwaving liquid-based foods in sealed jars is dangerous.
How Long Can You Microwave a Mason Jar?
How long you microwave mason jars depends on what you’re heating up and how much of it. It’s best to start with short bursts of 30 seconds to 1 minute and check periodically, rather than microwaving for one long stretch.
Foods like soup, oatmeal, chili, or veggies take a shorter time to heat through than dense foods like potatoes and meat. The size of the mason jar also matters as large glasses microwave for longer than smaller ones.
The key is to microwave in short increments to prevent overheating and evenly distribute the heat. Always check the temperature and stir before continuing.
Mason Jars Microwaving Dos and Don’ts
Before you even attempt to microwave a mason jar, there are some important dos and don’ts to keep in mind.
- Don’t microwave sealed jars – This is extremely dangerous. The pressure from heating can cause sealed jars to explode, sending scalding food and shattered glass everywhere. Always remove lids before microwaving.
- Use lower power – Microwaving on full power can lead to hot spots that may cause the jar to crack or shatter. Use medium to low power settings when microwaving mason jars to heat more gently and evenly.
- Check for the microwave-safe symbol– Some mason jars come with microwave-safe symbols. So first check to see if yours has one before placing it in the microwave (don’t just wing it).
Letting Food Cool
It’s important to let your microwaved food in the mason jar cool down before eating or handling it. The jar and food will be extremely hot right after microwaving.
Be very careful when removing the mason jar from the microwave. Use oven mitts or a thick towel to grasp the jar and set it on a heat-resistant surface like a granite or wood counter. Avoid any cold or wet surfaces that could cause the hot glass to crack.
Allow the microwaved food in the mason jar to stand for several minutes before opening or eating. This gives the temperature inside the jar time to even out and cool slightly. Attempting to open or eat piping hot food risks burns. Let it cool to a safe temperature before digging in.
Give the food a quick stir or shake if possible before serving, since microwaves create hot and cold spots. Let it stand a minute or two longer after stirring.
Wrapping Up
When it comes down to it, you can microwave mason jars, but you need to be careful. Mason jars are made of tempered glass so they can withstand quick heating, but thermal shock from drastic temperature changes can cause them to break.
So don’t take any chances, follow the proper safety precautions to avoid accidents and even injury.
Sources
- I Will Just Fix it Myself. (2023). Can You Microwave Mason Jars? (And Are They Oven-Safe). Retrieved from https://illjustfixitmyself.com/can-you-microwave-mason-jars/
- Jar and Can. (n.d.). Can You Microwave Mason Jars. Retrieved from https://jarandcan.com/can-you-microwave-mason-jars/
- Foods Guy. (n.d.). Can Mason Jars Go In The Microwave?. Retrieved from https://foodsguy.com/can-microwave-mason-jars/
