How To Seal Mylar Food Storage Bags | Build a Stash

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If you are looking for a new secret weapon for food storage, Mylar bags are the answer. They have the power to store foods for up to 30 years. Crazy, right?

Everything you need to know about Mylar bags and long-term food storage and sealing can be found here. We teach you proper assembly, the importance of oxygen absorbers, and how to heat seal your bags. This technique is the best shortcut to long-term food storage capacity compared to vacuum sealing.

Mylar food storage bags can store dried foods like grains for up to 30 years when sealed correctly. Mylar is excellent due to its affordability, ease of setup, flexibility, and non-porous features. Other competing long-term food storage techniques require more in-depth learning and setup requirements, making this the most straightforward choice for beginners.

After testing different foot storage solutions, we can confidently recommend Mylar. The straightforward explanation and step-by-step guide should make this method uncomplicated for anyone to understand.

Table of contents


What You Need To Get Started

Before we can begin the sealing process of a Mylar food storage bag, we need to gather everything and assemble it for a seamless setup. The reason for this is because once you open the oxygen absorbers, they must be sealed right away.

The fast-acting nature of the oxygen absorbers is why everything must be in place beforehand. Here is a list of the necessary items needed for successful sealing and storage.

  • A bucket and lid
  • Mylar bags for every bucket
  • Oxygen absorbers for every bucket
  • Heat source (Iron preferred)
  • Your food
  • Something to scoop your food
  • Permanent marker

Mylar Bag Food Storage Sealing

Now that you have everything ready, we can get started.

1. Place Mylar Bags into Buckets

Start by placing the empty Mylar bags into buckets. Line up the buckets for easier access once we start pouring food inside.  

It is best to view the process like an assembly line, and you can make your way down the line for each step and then move onto the next step with ease.

2. Load the Food into the Bags

Now is the time to grab your scooper and begin filling up each bag with food. As you fill each bag, shake the bags a few times to ensure they are packed tightly to eliminate the potential for air pockets.

Leave between 3-5 inches of space near the top of the bags for when we seal them. If you overfill, it will become difficult to close the bags.

3. Label Each Bag Appropriately

You can label a few ways, but we recommend writing with a permanent marker directly on each side of the bag. Be sure to put both the type of food in the bag and the date you store it.

To avoid fading on your writing, you can put a piece of clear tape over the label to last longer.

4. Allow the Sealer to Heat Up & Partially Seal the Bag

We highly recommend using a flat iron hair straightener to get the job done as a heat source. If you have not done so already, turn on your flat iron to allow it to heat up.

While that is happening, you have the time to partially seal the bag up until the final few inches near the top. Remove any leftover food pieces that could block the seal too.

5. Add Oxygen Absorbers

Once you open the oxygen absorbers, it takes a few hours (2-4) before they start to work. We always recommend waiting until the last moment to open them to be safe.

Put the oxygen absorbers at the top of the bag as quickly as possible. Don’t worry. You don’t need to bury them within the food for them to work correctly.

The size of the bag will determine how many oxygen absorbers you should use. A one-gallon bag requires one single 300cc oxygen absorber. For each gallon, aim for roughly 300cc. Putting extra in the bag will only help.  

6. Seal the Bag

Sealing the bag should be done as quickly as possible after inserting the oxygen absorbers. Push the sides of the bag all the way to get out the remaining air before applying the heat.

Your flat iron should be ready to go by now. Start in the middle of the bag and begin applying pressure gradually while moving to the edges. This helps to create a more even seal.

7. Check the Seal and Cover

Inspect the seals after completion to make sure it is thoroughly sealed. The process takes up to 12 hours to completely remove all excess air from inside the bag.

Lastly, you can place the lid back onto the bucket and store them away. To help your food last longer, keep the bags in a cool area that doesn’t get too warm.

What is Mylar?

Mylar is a polyester film made from polyethylene terephthalate. The compound is slim, flexible, and lightweight, with excellent durability.

Mylar is also transparent, reflective, and chemically stable. It is used in various products you may be familiar with, like solar filters and helium balloons.

When made into food storage bags, oxygen absorbers are added to the equation to eliminate the oxygen presence upon sealing to 0.01%.  

What Foods Can You Put In Mylar Bags?

The Mylar bag storage method is meant for dry foods with low-fat contents. The key is to avoid any type of moisture, and foods with fat contain more moisture than you would expect.

Some of the essential foods you can store include:

  • Grains
  • Pasta
  • Flour
  • Sugar
  • Wheat
  • Oats

Remember, fat content is the enemy for long-term storage. There are plenty of foods that fall into these categories that cannot be sealed and stored.

For example, brown rice is incredibly high in oil and holds a much shorter shelf life than you would expect. This is not the only example.

  • Raisins
  • Nuts
  • Granola
  • Crackers
  • Brown Sugar

These foods are only suited for a shelf life between two to five years. While they can still be sealed in Mylar bags, the food would no longer be fresh or usable after this time frame.

How Long Will My Food Last In Mylar Bags?  

The exact shelf-life of a specific food relies on a few external factors. The most important being the temperature at which the food is stored while sealed in Mylar bags.

We recommend finding cool spaces in the house for storage to maximize shelf-life on your foods, and the USDA agrees. The recommended temperature for storage is a constant temperature ranging between 40-60 degrees at all times.

This list is a reasonable expectation for shelf-life on some of the most popular foods for Mylar bag storage.

Food Type Mylar Bag Shelf-Life
White Rice 10-30 years
Brown Rice 2-5 years
White Flour 10+ years
Whole-Wheat Flour 8-10 years
Pasta 20+ years
Nuts 1-3 years
Granola 1 year
Legumes 30+ years
Oats 5-10 years

Mylar Bags or Vacuum Sealed Bags: What’s Better?

There is a common misconception confusing the differences between Mylar bags and vacuum seal bags. The thought is that unless a bag holds the vacuum-sealed look, then it is not sealed correctly. This is not the case when using a Mylar bag.

Remember, the goal is to absorb oxygen, not air. So let’s see how the two stack up against one another.

Mylar Bags


  • Stronger and more tear-resistant.
  • Reasonably priced (both bags and oxygen absorbers)
  • Variety of sizes to choose from.
  • Able to seal bags with at-home products (Irons or Flat-irons)
  • Air transfer inside the bag is minimal.  


  • More susceptible to rodents.

Vacuum Sealed Bags


  • Freezer friendly for shorter-term food storage.
  • Handles larger quantity of food.
  • Quicker sealing process.


  • Vacuum packaging machine is expensive.
  • Plastic bags leak more and allow more air transfer.
  • Bags are transparent and susceptible to light.
  • Leaves more oxygen present.


Mylar bags are nearly indestructible and easily outrank vacuum-sealed bags as the best option for long-term food storage. Vacuum sealing is more intended for short-term products.

If you want to stash food away to last five years or more, Mylar bags are the only option. If you are looking for a new secret weapon for food storage, Mylar bags are the answer.