What to Know about Mylar Bags for Food Storage?

Last updated: May 21, 2024.
Writen by :
Eric Lu
Marketing at Bagnpouch

Mylar bags have emerged as a popular and effective food strorage solution. These versatile bags are designed to protect food from environmental factors that can lead to spoilage, making them an essential tool for long term food storage.

In this blog, we will explore the benefits of using Mylar bags, the types of foods best suited for storage in these bags, tips for sealing them properly, and how long you can expect your food to stay fresh. By the end, you'll have a comprehensive understanding of why Mylar bags are a top choice for preserving your food products.

Let's explore the advantages and disadvantages of storing food in Mylar bags together!

What are Mylar Bags?

Mylar bags are durable, flexible, and airtight storage bags made from a polyester film called BoPET (Biaxially-oriented polyethylene terephthalate). This material is known for its high tensile strength, chemical and dimensional stability, transparency, reflectivity, and gas and aroma barrier properties.

The construction of Mylar bags involves laminating layers of polyester with a thin layer of aluminum. This combination creates a robust barrier that prevents the entry of oxygen, moisture, and light, which are the primary factors that contribute to food spoilage. The aluminum layer reflects light and provides an additional layer of protection, while the polyester layers add strength and flexibility to the bag.

Historical Background and Various Uses of Mylar

Developed in the 1950s by DuPont, Mylar was initially used for insulation, blueprints, kites, and solar filters. Over time, its use expanded to food storage due to its excellent barrier properties. Today, Mylar bags are widely used for storing food, important documents, medical supplies, seeds, and electronics

Benefits of Using Mylar Bags for Food Storage

Food storage involves preserving surplus food for future use, ensuring its availability during times of scarcity or emergencies. This process uses various technologies and containers to keep food fresh and safe from spoilage. Mylar bags have become a popular choice for food storage due to their exceptional barrier properties and ability to extend the shelf life of various food items.

Let's explore the key benefits of using Mylar bags for food storage. 

  1. Extended Shelf Life: Mylar bags can help extend the food producdt shelf life, keeping it fresh for months or even years. The barrier properties of Mylar bags protect your food from exposure to oxygen, light, and moisture, which can all contribute to food spoilage.
  2. Protection from Environmental Factors: Mylar bags are strong and resistant to punctures, rips, and tears, providing a barrier against the elements. This protection ensures that your food remains safe from pests, humidity, and other environmental factors that can compromise its quality.
  3. Versatility and Customization: Mylar bags are flexible and can accommodate foods of various shapes and sizes. They can also be customized with different sizes, designs, and closures to suit your specific storage needs.
  4. Cost-Effective: Mylar bags can be purchased in bulk, making them an economical choice for long-term food storage. This affordability makes it easier for individuals and businesses to stock up on essential food items without breaking the bank.
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Why Are Mylar Bags Suitable For Food Storage?

Mylar bags are a popular choice for long-term food storage due to their exceptional barrier properties and the use of oxygen absorbers. Understanding how these elements work together can help you maximize the effectiveness of your food storage efforts.

How Mylar Bags Work?

  • Oxygen and Moisture Barrier: The polyester and aluminum layers in Mylar bags create an effective barrier against oxygen and moisture, preventing oxidation and mold growth.
  • Light-Reflective Properties: The aluminum layer reflects light, protecting the contents from harmful UV rays that can degrade food quality
  • Durability: The strength and puncture resistance of Mylar bags ensure that they can withstand long-term storage without tearing or breaking.
  • Versatility: Mylar bags can be used for a wide range of food items, from dry goods to dehydrated foods, making them a reliable choice for various storage needs.

Importance of Using Oxygen Absorbers

Oxygen absorbers play a crucial role in enhancing the effectiveness of Mylar bags for food storage. These small packets contain iron powder, which reacts with oxygen to form iron oxide, effectively removing oxygen from the sealed environment.

By eliminating oxygen, oxygen absorbers prevent the growth of aerobic bacteria, mold, and other microorganisms that can spoil food. This process also helps in preserving the taste, texture, and nutritional value of the food. 

What Foods Can be Stored in Mylar Bags?

Mylar bags are excellent for storing a variety of dry and low-moisture foods, which helps in extending their shelf life significantly.

  • Grains like Rice and Wheat: Their low moisture content makes them perfect for long-term storage.
  • Dried Legumes like Beans and Lentils: Their shelf life is significantly extended in Mylar bags.
  • Dehydrated Fruits and Vegetables: Mylar bags protect them from moisture and light, preserving their quality.
  • Dry Pasta: Its longevity is enhanced when stored in airtight Mylar bags.
  • Non-Perishable Baking Ingredients: Such as flour and sugar, which benefit from the moisture-proof nature of Mylar.

These foods, being low in oil and moisture, are less prone to spoilage, making them ideal candidates for Mylar bag storage.

What Foods Are Not Suitable for Long-Term Storage in Mylar Bags?

Certain foods shouldn't be stored in Mylar bags due to their moisture content and perishability.

Here are four types of foods to avoid storing in Mylar bags:

  • High Moisture Foods: Fresh fruits, vegetables, meats, and dairy products contain significant moisture, which can lead to mold and bacteria growth in the sealed, airless environment of Mylar bags.
  • Fatty or Oily Foods: Foods like nuts, seeds, and oily grains can become rancid over time due to fat oxidation, especially when stored without air in Mylar bags.

Key Factors Leading to Unsuitability:

  • Moisture Content: The high moisture in certain foods can encourage bacterial growth and spoilage in the absence of refrigeration.
  • Oxidation of Fats: The lack of air circulation in sealed Mylar bags can accelerate the oxidation of fats in oily foods, leading to rancidity.

These factors make such foods inappropriate for Mylar bag storage, necessitating alternative storage methods.

PS: While Mylar bags are great for certain dry goods, for those foods unsuitable for Mylar packaging, such as high-moisture or fatty items, consider using FoodSaver bags.

How long can food be stored in a Mylar bag?

For optimal food storage in Mylar bags, consider the ideal foods based on their recommended storage times.

It's important to note that foods with high oil or moisture content, such as nuts, chocolate, and crackers, have a shorter shelf life and should be rotated more often.

Storage TimeFood Products
Less than half a yearFreshly Milled Whole Grain Flours, Ground Coffee, Herbs, Spices
Between half year and 1 yearBrown Rice, Nuts, Seeds, Natural Granola
Between 1 and 3 yearsWhite Flour, Dried Fruit, Powdered Milk, Yeast
Between 3 and 5 yearsWhite Rice, Pasta, Rolled Oats, Dry Beans
Between 5 and 10 yearsWhite Sugar, Salt, Baking Soda, Baking Powder
More than 10 yearsHard Grains (e.g., Wheat, Corn), Freeze-Dried Meats, Freeze-Dried Vegetables

It's important to note that these storage times can vary based on factors like the initial quality of the food, the storage conditions, and the effectiveness of the sealing process.

How to Use Mylar Bags for Food Storage?

Using Mylar bags for food storage is a straightforward process that can significantly extend the shelf life of your food. This step-by-step guide will walk you through the preparation, filling, sealing, labeling, and storing of Mylar bags to ensure your food remains fresh and safe for the long term.

Step 1. Preparation

Before you begin, gather all the necessary supplies to streamline the process and ensure you have everything you need at hand. This includes:

  • Mylar Bags: Choose the appropriate size based on the quantity of food you plan to store.
  • Oxygen Absorbers: These are essential for removing oxygen from the sealed environment, preventing spoilage and extending shelf life.
  • Heat Sealer: A heat sealer, clothes iron, or hair straightener can be used to seal the bags.

Step 2. Label the Target Mylar Bag

Label the Target Mylar Bag

Before filling the bag, label it with the contents and the date of storage. This helps in easy identification and managing food rotation. Use a permanent marker for clear, long-lasting labels.

Step 3. Fill the Bag

When filling Mylar bags with dry food items, follow these tips to ensure optimal storage:

  • Use a Measuring Cup: This helps in accurately portioning the food.
  • Avoid overfilling: leave enough space at the top for sealing. Ensure that the food is dry as moisture can lead to spoilage.
  • Shake the Bag: After filling, lift and shake the bag to settle the contents and eliminate air pockets. This allows you to fit more food into the bag and ensures a more compact storage.
  • Keep the Sealing Area Clean: Ensure the top edges of the bag are free from food particles to achieve a proper seal.

Step 4. Add Oxygen Absorbers According to the Bag’s Size

Oxygen absorbers are essential for removing oxygen from the Mylar bag, which prevents oxidation and growth of aerobic pathogens.

The amount of oxygen absorber needed depends on the size of the bag and the type of food. Generally, use 300-500cc for a gallon bag.

Step 5. Heat-Seal the Mylar Bag

To seal the bag, you can use a standard clothes iron or a flat iron for hair.

Place a piece of cardboard or wood under the bag's opening, and run the hot iron over the top edge to melt the Mylar together, creating an airtight seal.

Ensure the seal is complete without any gaps.

Step 6. Store Your Mylar Bags in a Cool Place:

After sealing, place the bags in a cool, dry location away from direct sunlight. Basements, closets, or pantries are ideal. Avoid areas where temperatures fluctuate, as this can affect the food's shelf life.

By following these steps, you can effectively use Mylar bags to preserve a variety of dry goods for the long term, ensuring a stable and secure food supply.

Tips for Sealing Mylar Bags

If you want to effectively store your food using mylar bags, it's important to know how to properly seal them.

Here are some tips for sealing mylar bags for food storage:

  1. Use a heat sealer: A heat sealer is the most common and effective way to seal mylar bags. Simply place the open end of the bag between the heat sealer jaws and press down to create a tight seal.
  2. Double seal for extra protection: To ensure maximum freshness and protection, consider double sealing your mylar bags. This involves making a second seal about half an inch below the first seal.
  3. Remove excess air: Before sealing the bag, make sure to remove as much air as possible. Squeeze the bag gently to push out the air, or use a vacuum sealer if available.
  4. Store in a cool, dry place: After sealing the mylar bags, it's important to store them in a cool, dry place away from direct sunlight and extreme temperatures. This will help to prolong the shelf life of the food inside.

What Size Oxygen Absorbers Should Be Used with Mylar Bags?

The size of the oxygen absorbers needed depends on the volume of the Mylar bag and the type of food being stored.

For example, a 300-500 cc oxygen absorber is typically used for a one-gallon Mylar bag, while a 2000-3000 cc oxygen absorber is recommended for a five-gallon bag. It's better to use more absorbers than needed to ensure all oxygen is removed.

O2 Absorbers & Mylar Bags VS Vacuum Sealing

O2 Absorbers mylar bag
Vacuum sealing bag for food packaging

In a nutshell, vacuum sealing eliminates air from the bag and creates a tight seal. But adding oxygen absorbers to Mylar bags specifically targets oxygen removal, which is critical for preventing oxidation and extending shelf life.

The choice between the Mylar Bags & Vacuum Sealing depends on the type of food being stored and the desired outcome in terms of preservation. This comparison plays a vital role in understanding the unique advantages of Mylar bag packaging.

How to Choose Mylar Bag for Your Food Product?

Mylar bags are available in a variety of sizes to meet a variety of food storage needs.

They also come in a variety of shapes and sizes, including flat pouches, stand-up pouches, gusseted pouches, and more.

Selecting the appropriate Mylar bag for your food items involves considering several key factors to ensure optimal preservation.

  • Size Matters: Don't let your food's freshness be compromised by choosing a bag too large for your needs.
  • Thickness Equals Protection: Opt for a thicker mylar bag to shield your food from external harm.
  • Oxygen Absorbers: A must-have to maintain the integrity and flavor of your stored food.
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