How to Seal Mylar Bags Properly for Long-Term Storage
When it comes to long-term food storage, Mylar bags are one of the most reliable solutions available. If sealed correctly, they can preserve dry goods for up to 25 years. But simply filling and sealing isn’t enough, you need to follow precise steps to ensure the protection of your food and your peace of mind. This guide breaks down how to seal Mylar bags the right way using simple tools, correct labeling, and proper oxygen absorber placement.
What Is a Mylar Bag?
A Mylar bag is made from BoPET (biaxially-oriented polyethylene terephthalate), a strong polyester film with a reflective aluminum layer. These heat sealable Mylar bags are specifically designed to block moisture, oxygen, light, and pests four of the biggest threats to food longevity. Mylar is flexible yet tough, making it ideal for both short-term and emergency food storage.
What Are Mylar Bags Used For?
Mylar food bag storage is common among homesteaders, emergency preppers, and anyone looking to keep bulk dry goods fresh. Commonly stored items include rice, beans, oats, pasta, flour, powdered milk, and dehydrated foods. These bags are also used for protecting seeds, herbs, pet food, and even documents.
Which Material Is Used to Make a Mylar Bag?
Mylar bags are crafted using BoPET plastic coated with a thin aluminum layer. This material gives the bag its shiny surface and durability. It also enhances the bag’s oxygen and moisture resistance, which is why vacuum sealable Mylar bags are so effective at preserving food for the long haul.
Key Considerations Before Sealing Mylar Bags
- Use a permanent marker to label the bag with its contents and the sealing date.
- Labeling helps you rotate stock properly and track freshness.
- Fill the bag about three-quarters full, leaving 3 to 4 inches of space at the top.
- This extra space allows for a clean and secure seal.
- Add the correct number of oxygen absorbers based on bag size (typically 300cc per gallon of food).
- Oxygen absorbers remove air to prevent mold, insects, and spoilage.
Put Your Product in Mylar Pouches
Begin by filling your Mylar food bag with dry, low-oil content food. Shake the bag lightly to settle the contents evenly. Avoid filling it too much, as sealing space is essential.
Add Some Oxygen Absorbers
Place the oxygen absorber(s) on top of the food. Once opened, they start absorbing oxygen immediately, so move quickly. For large bags (1-gallon or more), use multiple absorbers if necessary. This step is non-negotiable oxygen leads to spoilage, and these absorbers are your first line of defense.
Seal the Mylar Bag
Sealing is where most mistakes happen. Here’s how to seal Mylar bags properly:
Smooth the top edge and remove any food particles. Fold the excess top if needed and ensure the absorber is inside. Then seal the top 1 inch of the bag, ideally going over it twice for a strong seal.
Now, choose your preferred method:
Use a Cloth Iron
A standard iron on the cotton or high heat setting works well. Lay the bag flat on a wooden board or ironing surface and press the iron across the top slowly. Hold for 3–5 seconds, then check for a complete seal. This is a simple and effective option for most users.
Use a Hair Straightener
This method works well for sealing smaller heat sealable Mylar bags. Clamp the straightener onto the top edge and move across slowly. This offers good control and heat, especially in tight spaces.
Use a Vacuum Sealer
Some vacuum sealable Mylar bags are textured and compatible with vacuum sealers. Not all vacuum sealers can handle Mylar, so make sure yours is designed for this material. This method removes air and seals in one go but may not be as common for thick foil-lined bags.
Use an Impulse Sealer
An impulse sealer is a heat tool designed specifically for sealing bags. It gives a clean, straight seal in seconds. This is the most professional method, ideal if you’re sealing many bags at once. Simply press the heated bar over the bag’s top and hold until sealed.
How to Label Your Mylar Bags
Always label your Mylar bags before sealing. Use a waterproof permanent marker to write the contents, packaging date, and (optionally) expiration date or weight. This ensures you know what’s inside without opening it later.
You can also use adhesive labels or pre-printed stickers for consistency. Proper labeling helps keep your pantry or emergency stash organized.
Conclusion
Sealing Mylar bags properly is the difference between long-lasting food storage and wasted supplies. Whether you’re using a cloth iron, impulse sealer, vacuum sealer, or hair straightener, the goal is the same create a tight, reliable seal and remove oxygen.
Don’t forget to label clearly, use the right amount of absorbers, and store your bags in a cool, dry, dark place.
Still wondering, are Mylar bags reusable? Yes they can be reused if carefully opened and the seal area remains intact.
For anyone committed to food security and preparedness, mastering how do you seal a Mylar bag is a critical step. Start today protect your food, your time, and your future.
