Can You Vacuum Seal Mylar Bags?
Partly. Many household bar sealers can heat-weld thin Mylar, though thicker 5 mil and above often needs an impulse sealer. What a standard external sealer cannot do is pull a vacuum through a Mylar bag, because Mylar is smooth and has no air channels. Mylar's intended partner is oxygen absorbers, not suction.
This question has two halves that get mixed together, and separating them answers it properly. Can your machine seal Mylar, and can your machine vacuum a Mylar bag? The answers are different.
Can it seal Mylar? Often yes, with limits
Mylar bags for food storage are a foil laminate with a heat-sealable inner layer, so a heat bar can weld them. Whether yours can depends on thickness and on how long your seal bar stays hot. Thin bags, around 3.5 mil, are usually within reach of a decent household sealer, especially on a moist or extended seal setting. At 5 mil and above, which is what most long-term storage advice recommends, many consumer bar sealers simply do not deliver enough heat for long enough, and you get a weld that looks fine and peels later.
The tools built for the job are an impulse sealer, which applies a defined burst of heat through the full thickness, or a flat hair iron clamped along the bag mouth, which is the common improvised method for small batches. Both are cheap compared with losing a bucket of rice.
Can it vacuum Mylar? No, not an external sealer
An external suction sealer works by drawing air out through the bag opening, and that only works if the bag walls are held apart by an embossed pattern. Mylar is smooth on the inside. The moment the pump starts, the walls collapse together and there is no path for the air. You will not achieve a meaningful vacuum no matter how long you run it.
A chamber sealer is the exception, because it removes air from the chamber around the bag rather than through the opening, so texture is irrelevant.
Why Mylar does not need a vacuum
This is the part worth understanding, because it changes what you should buy. Mylar is designed to be used with oxygen absorbers, small iron-based packets that chemically consume the oxygen inside the sealed bag. That approach removes far more oxygen than a household vacuum pump does, and it keeps working after sealing, which suction cannot. It is also why a properly packed Mylar bag goes tight and slightly sucked-in a day or two after sealing, with no pump involved at all. That is the absorber doing its job and it is a good sign, not a leak.
| What you want to do | Right tool | Notes |
|---|---|---|
| Long-term dry staples in Mylar | Impulse sealer plus oxygen absorbers | The standard combination for grains, beans, rice, pasta |
| Seal thin Mylar occasionally | Household sealer on extended seal | Test the weld by hand before trusting it |
| Actually evacuate a smooth bag | Chamber sealer | Removes air from the chamber, so texture does not matter |
| Fridge and freezer food | Embossed vacuum bags | This is what suction sealers are built for |
A note on doing both
Some people seal food in an embossed vacuum bag and then place that inside a Mylar bag with an absorber. It works, and the Mylar adds the light barrier that clear vacuum film lacks, but it is belt and braces rather than necessary. If the Mylar seal is sound and the absorber is correctly sized, the inner vacuum bag is adding cost more than shelf life.
For which method suits which food and timescale, see Mylar bags vs vacuum sealing, and for absorber sizing, how many oxygen absorbers do I need.
Frequently asked questions
Will a FoodSaver-style sealer seal Mylar?
It can often weld thin Mylar on an extended or moist seal setting. Thicker 5 mil and above frequently needs an impulse sealer. Test the weld by hand before storing food behind it.
Why will my sealer not suck the air out of a Mylar bag?
Mylar is smooth inside, so there are no channels for air to travel along. External sealers need embossed film to evacuate a bag through its opening.
Do I need both a vacuum and an oxygen absorber?
No. An absorber removes more oxygen than a household vacuum and keeps working after sealing. The absorber is the one that matters for long-term dry storage.
My Mylar bag went tight after a day. Is that a problem?
That is normal and expected. The oxygen absorber consumed the oxygen inside, which reduces the internal volume and pulls the bag in.