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How-To Guide

How to Seal Mylar Bags (3 Easy Ways)

Mylar bags come with resealable zips, but a heat seal is what makes them truly airtight for long-term freshness. Here's how to do it with tools you already own — no machine required.

Method 1: Clothes Iron (most common)

1. Fill the bag, leaving 1–2 inches of space at the top; squeeze out excess air
2. Lay the open edge flat over a hard surface (a wood board or book edge works)
3. Iron on medium-high (no steam), press the edge for 2–4 seconds
4. Check the seal — it should be fused and smooth. Re-press any gaps

Method 2: Hair Straightener (easiest)

Clamp the open edge and glide slowly across. The two heated plates seal both sides at once — most people find this easier than the iron.

Method 3: Impulse Sealer (for volume)

If you're sealing dozens of bags, a tabletop impulse sealer ($30–60) does each one in a second with a perfect factory-style bar seal.

Zip vs Heat Seal

Use the built-in zip for anything opened regularly. Add the heat seal for long-term storage, retail presentation, or tamper evidence — customers can tear the notch, open the seal, and still re-close with the zip.

All packaging is sold empty and intended for lawful storage of food, herbs, and dry goods.

Frequently Asked Questions

Do you need a machine to seal mylar bags?

No — a household clothes iron or hair straightener on medium-high heat seals mylar in seconds. Impulse sealers ($30–60) are faster for volume, but our bags also have resealable zip locks for everyday use without heat.

What temperature seals mylar bags?

Roughly 375–425°F. Press the open edge for 2–4 seconds; the layers fuse. Too hot melts through, too cool leaves gaps — test on one bag first.

Do mylar bags need oxygen absorbers?

For long-term food storage, yes — drop the absorber in just before sealing. For short-term retail packaging of dry goods, the zip lock and heat seal are usually enough.

How long do sealed mylar bags keep food fresh?

Properly heat-sealed multi-layer mylar with oxygen absorbers keeps dry staples fresh for years — it blocks light, moisture, and air, which are what degrade dry goods.