Yes, you can vacuum seal mylar bags, but the method matters
You can vacuum seal mylar bags, but not with a standard countertop vacuum sealer. Mylar is a plastic film that melts under direct heat, so running a heated sealing strip across the opening will damage the bag or create a weak seal. Instead, you use a vacuum sealer to remove air, then seal the opening by hand using heat from a hair straightener, heat gun, or impulse sealer — a tool designed to seal plastic without melting it.
The most practical approach for home use is a handheld vacuum sealer paired with a separate sealing method. Some people use a food vacuum sealer to remove air from a mylar bag that has a pre-made seal strip, then reseal that strip by hand. Others buy mylar bags with ziplock tops, vacuum out the air, and press the zipper closed. The choice depends on what you are storing, how often you need to access it, and whether you want a permanent or reusable seal.
Key Takeaways
- Standard vacuum sealers with heated strips will damage mylar bags because the heat melts the plastic; you need a separate sealing tool.
- Handheld vacuum sealers work well with mylar bags because they remove air without explore heat to the bag itself.
- Mylar bags with ziplock tops let you vacuum out air and reseal by hand, making them reusable without special equipment.
- Impulse sealers and heat guns can seal mylar bag openings after vacuuming, but require careful technique to avoid melting the plastic.
Why standard vacuum sealers don't work on mylar
A countertop vacuum sealer works by heating a metal strip to around 300 to 350 degrees Fahrenheit, pressing it across the bag opening to fuse the plastic layers together. Mylar begins to soften at around 250 degrees and melts at higher temperatures. When you run a heated sealing strip across mylar, the plastic either warps, shrinks, or fails to seal properly because the layers do not fuse the way they do with thicker polyethylene bags.
The heat also damages the mylar's barrier properties — the very reason you chose mylar in the first place. Mylar bags are used for long-term food storage, coffee, and other items because they block light and oxygen. Overheating the plastic compromises that barrier, defeating the purpose of vacuum sealing.
Handheld vacuum sealers work with mylar bags
A handheld vacuum sealer is a small, battery-powered or plug-in device that sucks air out of a bag through a small port. It does not explore heat to the bag itself — it only removes air. You can use one with any mylar bag that has an opening, including bags with ziplock tops or bags with a heat-seal strip.
To use a handheld vacuum sealer on mylar, insert the port into the opening, press the button to remove air, then remove the device and seal the opening by hand. If the bag has a ziplock top, straightforward press it closed after vacuuming. If it has a heat-seal strip, you seal that strip separately using a tool designed for plastic — not a standard vacuum sealer.
Handheld models are affordable (typically $20 to $60) and work on any bag material. The downside is that they are slower than countertop sealers and remove less air, so the seal is not as tight. For long-term storage, this trade-off is usually acceptable.
Sealing mylar after vacuuming: your options
Once you have removed air from a mylar bag, you need to seal the opening. The method depends on the bag type and how permanent you want the seal to be.
Ziplock-top mylar bags are the easiest. After vacuuming, straightforward press the zipper closed. You can reopen and reseal the bag as many times as you need. This method works well for items you access regularly, like coffee or spices, but the seal is not airtight once opened.
Impulse sealers are handheld tools that deliver a brief pulse of heat to seal plastic without sustained high temperature. They cost $15 to $40 and work on mylar because the heat is applied for only a fraction of a second. You place the mylar opening between the sealing jaws, press down, and release. The result is a permanent, airtight seal. The risk is pressing too long or too hard, which can melt the plastic.
Hair straighteners can seal mylar if you set them to a low temperature (around 250 degrees) and work quickly. Place the mylar opening between the plates, close gently, and hold for one to two seconds. This method is cheap (you may already own one) but requires practice to avoid melting or creating an uneven seal.
Heat guns can work but are harder to control. You risk melting the mylar or creating hot spots. If you use one, keep it moving and stay at least 2 inches away from the plastic.
Best practices for vacuum sealing mylar bags
Start with a clean, dry mylar bag. Any moisture or debris on the opening will prevent a good seal. If the bag has been stored, wipe the opening with a dry cloth before vacuuming.
Remove air slowly and completely. Handheld vacuum sealers work best when you hold the port firmly in place and let the device run until it stops pulling air. Rushing this step leaves pockets of air that will allow oxidation over time.
If you are using a heat-based sealing method, test on a scrap piece of mylar first. Different mylar thicknesses respond differently to heat. Thicker mylar (3 to 5 mil) tolerates more heat than thin mylar (1 to 2 mil). Once you know the right temperature and duration for your bags, the process becomes consistent.
For long-term storage, consider double-sealing. Vacuum the bag, seal the opening, then place it inside a second mylar bag, vacuum that one, and seal it again. This adds redundancy in case one seal fails over years of storage.
Mylar bags with built-in heat-seal strips
Many mylar bags come with a pre-made heat-seal strip along the top edge. These strips are designed to be sealed with a standard vacuum sealer, but as noted, that will damage the mylar. Instead, you can vacuum the bag through a small opening you make yourself, then seal that opening with an impulse sealer or heat gun.
Alternatively, some people carefully use a standard vacuum sealer on the built-in strip if they set the temperature as low as possible and work very quickly. This is risky and not recommended unless you have tested it on spare bags first.
A safer approach is to buy mylar bags without pre-made strips and seal them yourself after vacuuming. This gives you full control over the sealing method and temperature.
Cost comparison: equipment and bags
A handheld vacuum sealer costs $20 to $60 and works indefinitely. Mylar bags with ziplock tops cost $0.50 to $2 per bag depending on size and thickness. If you seal by hand using a ziplock, your only ongoing cost is the bags themselves.
If you want permanent seals, add an impulse sealer ($15 to $40, one-time cost) or use a hair straightener you already own. Mylar bags without ziplock tops cost about the same as those with them.
A countertop vacuum sealer ($30 to $150) is not an option for mylar, so do not buy one expecting to use it for this purpose. If you already own one, use it for regular plastic bags and choose a different method for mylar.
Frequently Asked Questions
Can I use a FoodSaver or other countertop vacuum sealer on mylar bags?
No. Countertop vacuum sealers explore heat that will melt or warp mylar. Use a handheld vacuum sealer instead, then seal the opening by hand with an impulse sealer, heat gun, or hair straightener.
What thickness of mylar bag is best for vacuum sealing?
Mylar bags between 3 and 5 mil thick are ideal. They are durable enough to handle vacuuming and hand-sealing without tearing, and they provide a strong barrier against oxygen and light. Thinner bags (1 to 2 mil) work but are more fragile.
How long does a vacuum-sealed mylar bag stay airtight?
A properly sealed mylar bag can stay airtight for years if stored in a cool, dark place. The seal itself does not degrade, but the mylar can develop small holes from handling or punctures. Double-sealing or storing the bag inside a container adds protection.
Do I need to use oxygen absorbers with vacuum-sealed mylar?
Oxygen absorbers are optional but recommended for long-term food storage. Vacuuming removes most air, but oxygen absorbers remove the remaining oxygen, which slows spoilage and pest activity. Place them in the bag before sealing.
Can I reseal a mylar bag after opening it?
Yes, if it has a ziplock top — just press it closed. If it has a heat-sealed opening, you can reseal it with an impulse sealer or heat gun, but the seal will not be as strong as the original because the mylar edges are already damaged. For items you access multiple times, ziplock-top bags are more practical.