Can You Microwave Ziploc Bags [Tested – Check What Happened]

Can You Microwave Ziploc BagsZiploc bags are one of the most popular and versatile plastic bag products on the market. Whether you’re using them in the lunchbox, to store leftovers, or simply as a storage container, Ziploc bags are perfect for a variety of uses.

As convenient as they are, one question has plagued many users: can you microwave Ziploc bags?

The short answer is yes. Ziploc bags are safe for use in microwaves and are FDA approved for temperatures associated with reheating and defrosting food. However, the manufacturer has highlighted some specific guidelines that you need to follow to do it safely.

Our article seeks to answer that question and explain how to microwave Ziploc bags safely and answer some of your frequently asked questions about this product. But first, a little background on Ziploc bags and what makes them unique.

About Ziploc Bags

Understanding the history of Ziploc bags and how they became one of America’s favorite sandwich bags will help you grasp what they are.

Invented in 1968 by Dow Chemical Company, Ziploc is an American brand of clear plastic storage bags and containers. The name Ziploc is a registered trademark of S.C. Johnson & Son.

The name is derived from zip lock, a seal that zips or closes itself once the air has been removed. Since their invention, the brand has expanded its product line to include containers and freezer bags for individual items and family sizes for household use.

So, now that you know who invented them and how they came to be let’s define Ziploc bags. They are plastic bags with a zipper-style closure that allows air to escape when sealed. This prevents wet items from seeping into other contents in your storage containers.

Some of their more popular uses include storing food, protecting clothing, and keeping small objects organized. They can also be used as sandwich or snack bags.

What Makes Ziploc Bags Microwave Safe

There are specific characteristics that make some plastic products microwave safe. Therefore it is highly advised to check for these properties before using other plastics to store or cook food in microwaves.

Let’s look at the five properties that make Ziploc bags microwave safe.

1. Features a Microwave-safe Label

Ziploc bag has a label on its back that informs whether you can microwave it or not. Also referred to as microwave-ready labels, they indicate whether an item is designed and tested for heat resistance in microwave ovens; hence suitable for heating purposes.

2. Heat Resistance

Different plastics retain heat differently, depending on their chemical makeup and molecular density. Food grade polymers such as polyethylene usually have better thermal insulation properties when compared to polypropylene. A regular Ziploc bag will withstand heat up to a temperature of 90.6 degrees Celsius (195 degrees Fahrenheit).

3. BPA Free

The number one rule of using plastics in microwaves is never to put anything in your meal containing bisphenol A (BPA). This chemical compound is harmful and can cause several side effects when heated and ingested. Ziploc bags are free from BPA contamination as they contain no toxic chemicals during their manufacturing process.

4. Controlled Permeability

Permeability refers to how fast liquids or gases get through plastic objects. If the material has high permeability, chances are it will leak hazardous particles or gases into your food while cooking in your microwave. As a result, regulated permeability is required when cooking in a microwave due to the high temperature.

However, all Ziploc bags are designed to have lower levels of negative ions. As a result, its molecular structure retains its physical integrity for extended periods.

I tested

Safety Precautions When Microwaving Ziploc Bags

Before we delve into how to microwave your Ziploc bag safely, let’s first take a look at some of the safety precautions that Ziploc has provided:

1. Put the Bag on a “Microwave-Safe” Container

When microwaving your Ziploc bag, make sure it is placed on a microwave-safe container such as glass or ceramic plates or bowls. Ziploc bags will melt at temperatures above 90.6 degrees Celsius, so always keep safety in mind.

2. Cooking Is Not Recommended

While it’s okay to defrost and heat food in a Ziploc bag, cooking is not recommended. The plastic used to make Ziploc bags is a low-density polyethylene, which can melt if too much heat is present.

However, use caution if you choose to cook with a Ziploc bag. Monitor for signs of overheating, such as discoloration of plastic on your microwave walls, and adjust your time based on these signs.

3. Avoid Overheating

Ziploc bags will begin to melt if heated for too long. A regular Ziploc bag will withstand only up to a temperature of 80 to 90 degrees Celsius. If your bag overheats, you may get burned or even damage your microwave.

As a result, using other microwave-safe containers for a prolonged period will offer a safer way to reheat

4. Unseal the Bag

It is never a great idea to microwave a Ziploc bag that has been sealed completely. Doing so could cause superheated steam to build up in the bag, which can cause it to explode or leak and result in injury.

To be on the safe side, if you notice beads of moisture (or any condensation) forming, remove the bag from the oven immediately. This is a sign that there may be excess pressure building up inside.

5. Make your food portions smaller and more uniform

If you don’t cut your food into uniform pieces, it won’t heat appropriately in a Ziploc bag. Ideally, you should divide your food into cubes or slices of roughly equal size.

This is incredibly significant if you intend to reheat your food. If your portions are uneven, some parts will continue to cook while others remain undercooked. Smaller pieces also heat faster than larger ones.

I Did an Experiment on How to Microwave a Ziploc Bag

I wanted to test if one can really microwave a Ziploc bag. In that case, I took a Ziploc bag and filled it with water. I then tested the temperature of the water before putting it in the microwave.  I then microwaved the water at intervals of 1 minute. I used an infrared thermometer to take the temperatures at each interval

Findings From the Experiment of Microwaving a Ziploc Bag

The initial water temperature was 22.1 degrees Celcius. After microwaving for one minute, the paper was warm to touch and the temperature of the water rose to 29.4 degrees Celsius. By the second minute, the steam had started to build up but it had a satisfactory temperature of 61.6 degrees Celcius. The water had started to boil by the third minute. The bag had ballooned as a result of steam buildup. The temperature of the water was 78,7 degrees Celcius.

This is how the paper looked by the third minute

Can You Microwave Ziploc Bags

The table below shows the temperatures at each minute

Time in MinutesTemperature Change Per Min
0 minute22.1 degrees Celsius
1 minute29.4 degrees Celsius
2 minutes61.5 degrees Celsius
3 minutes78.7 degrees Celsius


Two minutes are enough to microwave food in a Ziploc bag. Beyond this temperature, steam may build up in the Ziploc bag causing it to burst. Therefore the ideal temperature for microwaving a Ziploc bag is below 75 degrees Celsius which can be around 2 to 2 and a half minutes. This is especially for reheating food in the microwave.


How to Safely Microwave Ziploc Bags

There is a lot of misinformation about using Ziploc bags in microwaves. This short guide will explain step-by-step what you can do and what you should not do with your plastic bags.

Hopefully, after reading it, you will have no qualms about using your zippered plastic bags in microwaves.

Things You Will Need

  • A Ziploc bag
  • A microwave

Step 1 – Cut the Food into Equal-Sized Cubes

When heating food in a microwave, ensure to cut the food into equal-sized pieces. Large chunks of food require longer microwaving times than smaller pieces, and those differences can lead to uneven cooking.

Step 2 – Avoid Fatty or Sugary Foods

When microwaving Ziploc bags, ensure that you avoid using fatty or sugary foods. While all molecules have some level of water, fat and sugar molecules collect more electromagnetic waves than water molecules. This can melt Ziploc and contaminate your food, making it unsafe for consumption.

Step 3 – Plug in the Microwave

Make sure your microwave is powered on and plugged in. A beeping sound indicates that your microwave is operational. If you don’t hear one, check if your microwave has any issues and try again.

Step 4 – Unseal the Ziploc Bag

Remove the seal from the Ziploc bag before microwaving to prevent steam build up in the bag. Doing so will allow any steam to escape and help you avoid pressure build-up in the bag.

Step 5 – Set the Timer to 30 Seconds

Once you have your Ziploc bag with either food or drink inside the microwave, it is time to set your timer. If you’re going to microwave a liquid-based dish, keep in mind that liquids heat up faster in the microwave.

Step 6 – Heat at Low or Medium Settings

It’s vital to keep in mind that Ziploc bags are only heat-resistant up to a temperature of 80 to 90 degrees Celsius. This means it’s best to avoid using high settings and stick with low or medium. Failure to do so will render your bag unusable due to damage caused by the high temperatures.

Step 8 – Use the Stop/Pause Button

If you need to pause the program, press the Stop/Pause button before opening the door. You can continue when you are ready. At times, if your food is too close to the edge of your container, it may prompt an automatic stop for safety reasons.

Step 9 – Remove Your Ziploc Bag

Once you are done microwaving your Ziploc bag, let it cool for a few minutes before taking it from the microwave. If you try to remove it while it is still hot, you will most likely burn yourself.

Final Step – Clean Your Microwave

Remember to clean your microwave after you’ve done heating. Simply soak a towel in water and wipe away any stains or excess food that may have accumulated.

Faqs About Can You Microwave Ziploc Bags

1. Is it safe to microwave food in Ziploc bags?

Yes, it is. Ziploc bags are safe for use in microwaves and are FDA approved for temperatures associated with reheating and defrosting food.

2. Can you cook in a Ziploc bag?

It is not recommended to cook in a ziploc bag. These bags are heat-resistant up to 80 t0 90 degrees Celsius. Cooking at a higher temperature than that can lead to severe damage and even warping/melting your bag.

If you wish to cook in a Ziploc bag, place it in a microwave-safe container. This way, you avoid any damage caused by extreme temperatures.

3. Are Glad sandwich bags microwave safe?

Glad sandwich bags are indeed microwave safe. They’re made of heat-resistant materials and can go in the microwave without contaminating your food or damaging your appliances.

The plastic will not melt or otherwise become damaged, so you can use them as intended. They can be microwaved an unlimited number of times, so there’s no need to be concerned about recycling them.

4. Can you microwave a Ziploc bag Reddit?

Yes, absolutely. Ziploc bag Reddit is microwave-safe. If you’re uncertain, check with the manufacturer, as not all bags are microwave safe.

5. How hot can you get a Ziploc bag?

Can You Microwave Ziploc BagsZiploc bag can only get hot up to a temperature of 80 to 90 degrees Celsius. They’ll start to melt, distort, or ignite after that. It is recommended that microwaves be set at or below 175F for any food in a Ziploc bag.

6. Does Glad make Ziploc bags?

No, Glad does not make Ziploc bags. Ziploc bags are made by a different company called SC Johnson, while Glad makes garbage and kitchen trash bags.

7. What are Glad sandwich bags made of?

Glad sandwich bags are made of FDA-approved plastic, specifically LDPE (low-density polyethylene). This is essentially food-grade plastic. These bags are BPA-free and, therefore, unlikely to leach into your food.

8. How big is a snack-size Ziploc bag?

According to Ziploc’s official website, snack size bags measure 6.50in Width x 3.25in Length and hold 1 cup of dry ingredients. This site is also referred to as snack-size, lunch bag, or sandwich bag.

Bottom Line

Microwaving Ziploc bags is safe, as we’ve learned, but there are a few precautions you should take before doing so.

Though they’re stable for short periods, heating them with high heat may cause them to warp or melt. Instead of heating your food in the microwave at a high-power setting, small heat amounts at a time on a low-power mode.

Also, remember to unseal your bag before you put it in for defrosting or heating; otherwise, it may explode from the pressure build-up.

Check out the video for more information


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