Sealing Mylar bags properly is essential for preserving the freshness and longevity of your stored food or other items. Whether you're prepping for long-term food storage or simply want to keep your goods airtight and protected, knowing how to seal Mylar bags effectively can make all the difference. In this guide, we'll walk you through the preparation steps, the tools you need, and the best sealing methods available from impulse sealers to household irons to ensure your Mylar bags are sealed securely and efficiently.
Preparation Before Sealing
Tools vs Supplies Needed:
- Mylar bags (typically 3–7 mil thickness)
- Heat source: impulse sealer, clothing iron, or hair straightener
- Oxygen absorbers (to remove oxygen and extend shelf life)
- Flat surface such as a cutting board for stability during sealing
Pre-packing Tips:
- Leave about 6 inches (15 cm) of space at the top of the bag for sealing
- Ensure the food inside is dry and suitable for long-term storage to prevent spoilage.
Sealing Methods vs Comparison
Impulse Sealer
- How to use: Place the open edge of the Mylar bag between the heated sealing bars, press down firmly for 2–3 seconds, then slowly release to allow the seal to cool.
- Pros: Quick, consistent, and secure seals ideal for long-term storage.
- Cons: Higher initial cost; some impulse sealers may not accommodate thicker 7-mil bags.
Clothing Iron
- Heat setting: Use the “wool” or medium heat setting.
- Method: Place the bag on a flat surface and press the iron firmly across the top edge of the bag for a tight seal, usually requiring one or two passes.
- Pros: Common household item, budget-friendly, and effective.
- Cons: Requires a flat surface and offers less precision compared to impulse sealers.
Hair Straightener
- Recommended temperature: 375–425 °F (190–218 °C).
- Method: Clamp the bag edge with the straightener and slowly move it across the top to seal.
- Pros: Easy to handle, great for small batches or occasional use.
- Cons: Narrow sealing area may require multiple passes for a secure seal.
Vacuum Sealers
- Most vacuum sealers do not reach the temperatures needed to seal thick Mylar bags properly.
- Hack: Use a textured sealing strip (like Seal-a-Meal style) to vacuum out the air first, then finish sealing the bag top with a clothing iron or impulse sealer for an airtight closure.
Additional Tips
- Always test the seal by gently pulling on the sealed edge to ensure it is airtight.
- Use oxygen absorbers inside the bag before sealing to remove residual oxygen, which helps prevent spoilage.
- Even Mylar bags with zippers should be heat sealed above the zipper for maximum protection.
- If reusing Mylar bags, cut open below the original seal, refill, add new oxygen absorbers, and reseal.
By following these preparation steps and choosing the sealing method that best fits your tools and needs, you can confidently seal Mylar bags to protect your stored items from moisture, oxygen, pests, and other damaging elements, ensuring long-lasting freshness and safety.
Step-by-Step Sealing Instructions
Sealing Mylar bags correctly is crucial to ensure your food or items stay fresh and protected for the long term. Follow these detailed steps to achieve a perfect seal every time.
Step 1: Fill the Bag vs Add Oxygen Absorber
- Fill your Mylar bag with the desired contents, leaving about 6 inches (15 cm) of headspace at the top.
- Insert the oxygen absorber last, placing it on top of the food inside the bag. This absorber will help remove oxygen and extend shelf life.
Step 2: Remove Excess Air
- Gently press down on the bag to squeeze out as much air as possible before sealing.
- Keep in mind that oxygen absorbers remove oxygen but do not create a total vacuum, so some air will remain.
Step 3: Heat Seal the Bag
- Select your preferred sealing method (impulse sealer, clothing iron, or hair straightener).
- Carefully seal the bag, ensuring the seal is complete and even across the entire width of the bag’s opening.
Step 4: Test the Seal
- After sealing, gently squeeze the bag to check for any air escaping.
- If you notice any leaks or are unsure about the seal’s integrity, apply a second seal either above or below the first to reinforce it.
Practical Tips
-
How much air is okay?
A small amount of air is acceptable because oxygen absorbers remove oxygen molecules, not all the air inside the bag. -
Where to seal?
Seal about ¼ inch from the top of the bag. For zip-top Mylar bags, always seal above the zipper to ensure airtight protection. -
Be cautious with sharp items:
Long pasta, rough grains, or other sharp-edged foods can puncture the bag as the oxygen absorber contracts. Consider using protective layers or packaging to avoid damage. -
How to reseal bags:
If you need to reuse a Mylar bag, cut just below the original seal, insert a new oxygen absorber, and reseal the bag using your heat source. -
Use protective storage:
Store your sealed Mylar bags inside food-grade buckets or plastic totes to prevent accidental punctures and extend storage life.
FAQs
-
Do you always need oxygen absorbers?
Yes, except when storing items like sugar or salt that do not spoil due to oxygen exposure. -
Should you use absorbers with sugar or salt?
No, oxygen absorbers can cause clumping and hardening in these products. -
Can Mylar bags be reused?
Yes, if you carefully cut open the bag and reseal it properly with a new oxygen absorber. -
How to store sealed Mylar bags?
Keep them in cool, dark places, preferably inside buckets or bins for added protection against moisture and pests.
In conclusion, Sealing Mylar bags properly involves choosing the right sealing method, adding oxygen absorbers, heat sealing the bag securely, and verifying the seal’s integrity. For frequent storage, impulse sealers offer speed and reliability, while clothing irons or hair straighteners are excellent budget-friendly options for beginners.
Ready to start your long-term food storage journey? Browse Kimecopak’s eco-friendly Mylar bags and packaging solutions to find high-quality products designed to keep your food fresh and safe for years to come!
