Custom Mylar Bags for Freeze Drying
Custom mylar bags for freeze-dried food, from 100 units. A foil laminate thick enough to keep oxygen out for years, a size matched to what one tray yields, and print that carries a rehydration panel — because a freeze-dried product is only as good as the bag that keeps the air off it.
The food will last 25 years, if the bag does
- Structure
- PET / aluminum foil / PE laminate, 5 or 7 mil
- Sizes
- Pint, quart, half gallon, gallon; cut to your tray yield
- Closure
- Heat seal; zipper above the seal for the retail version
Get a price for Mylar Bags For Freeze Drying
Send the size and quantity — we reply the same working day with a price, a dieline and a date. Artwork optional at this stage.
- Free dielineThe flat drawing comes with the quote, before you commit.
- Proof before pressNothing is printed until you have seen it laid on the dieline.
- Die kept for reordersTooling is paid once. Every reorder skips straight to press.
- Quoted in four marketsUS, UK, Canada and Australia, in the delivery currency.
What the laminate has to stop
Two things: oxygen, which turns fats rancid and fades color, and water vapor, which softens the product and lets microbes back in. A clear plastic bag stops neither for long. A true mylar bag is a laminate — polyester on the outside for strength and print, an aluminum foil layer in the middle as the barrier, and polyethylene inside as the heat-seal layer. The foil is what makes it work; a metallized film with a sprayed-on aluminum layer looks the same and has a barrier many times weaker.
For freeze-dried storage we use a genuine foil laminate at 5 mil or heavier. The thinner, metallized bags sold for snacks are not the same product.
| 5 mil foil laminate | The storage standard — pantry and emergency stock, 10–25 years |
|---|---|
| 7 mil foil laminate | Heavier, puncture-resistant, for sharp or dense products |
| Metallized PET, 3.5 mil | Snack retail only; not for long-term freeze-dried storage |
Sized to the tray, not the ounce
A home or small-batch freeze dryer produces a fixed volume per tray, and the bag should take one tray, or a clean fraction of it, so filling is a matter of tipping. Freeze-dried food is light and bulky — a pound of strawberries becomes a few ounces that still fill a quart — so the bag is sized by volume, and a bag sized by weight from a wet-food chart will be far too small. We keep the range that matches standard trays and cut to order for larger machines; the family-size version is on our gallon mylar bags page for bulk storage.
Leave two inches of headspace above the fill line for the seal and the absorber. A bag filled to the top cannot be sealed flat and the seal will fail.
Oxygen absorbers, and the seal
- One 300 cc absorber for a quart, 500 cc for a half gallon, 1000–2000 cc for a gallon; more if the product is coarse and traps air.
- Absorbers go in last, and the bag is sealed within minutes, or they are spent on the room rather than the bag.
- A flat-jaw impulse sealer at the right temperature for the PE layer; we print the seal temperature on the bag if you ask.
- A properly sealed and absorbed bag pulls in and goes hard within a day. One that stays soft has a leak or a spent absorber.
Print that tells the customer what to do with it
Freeze-dried food is unfamiliar to most people. The bag has to carry the rehydration instructions, the water ratio, the packed and best-by dates, and the net weight — which is small and surprises customers, so the front panel should show the rehydrated yield too. A matte print on the foil reads better than gloss under kitchen light, and a small window is possible but it is a hole in the barrier; we discuss when it is worth it on our windowed mylar bags and what the window costs page.
Mylar Bags For Freeze Drying — specification
The rows that are specific to this build first, then what applies to every job we run. Anything not listed is a question, not a limit — send the brief.
This build
- Structure
- PET / aluminum foil / PE laminate, 5 or 7 mil
- Sizes
- Pint, quart, half gallon, gallon; cut to your tray yield
- Closure
- Heat seal; zipper above the seal for the retail version
- Barrier
- True foil layer; OTR below 0.005 cc/m²/day
- Up to 10 colors, matte or gloss; rehydration and date panels
- Minimum
- 100 bags
On every job
- Print process
- Flexo in up to ten colors on the outer film, or digital for short runs and changing artwork.
- Color
- A white underprint carries normal color on metallised or clear film. Without it, every color takes on what is beneath it.
- Tolerance
- Bag width plus or minus 2 mm, length plus or minus 3 mm. Film stretches, so a barcode is verified on a filled bag.
- Tooling
- Print plates or cylinders per design, kept. There is no cutting die — the bag is formed and sealed rather than cut.
- Food contact
- A food-grade sealing layer against the product, with the inks trapped between layers rather than on the food face.
- Sustainability
- Mono-material PE or PP where the shelf life allows, which recycles as a soft plastic. A foil laminate does not.
- Artwork
- Vector PDF or AI, 3 mm bleed, 4 mm safe area, fonts outlined. We check every file and send a proof before press.
- Dieline
- Supplied free with the quote, before you commit. Yours whether or not you order.
- Sample
- A plain unprinted sample at the finished size on request, for fit and construction.
- Reorders
- Skip the tooling and go straight to press at a lower unit price.
- Lead time
- Quoted with the price against your fill date rather than promised before we have seen the spec.
- Markets
- United States, United Kingdom, Canada, Australia — priced in the delivery currency, freight included.
Boards and films we build mylar bags for freeze drying on
A flexible pack is a stack of films laminated together, and the middle layer is the barrier. The structure is chosen from the shelf life you need and what you want to be able to say about recycling.
PET / PE
A printable outer and a sealing inner. Moisture barrier, modest oxygen barrier. The everyday laminate for dry goods sold quickly.
2-ply, 70–110 micronPET / AL / PE
Aluminum foil in the middle: the strongest barrier against light, oxygen and moisture. Coffee, supplements, anything with a long shelf life.
3-ply, 90–130 micronMetallised PET
A vapour-deposited metal layer. Bright, lighter and cheaper than foil, with a weaker barrier. Most silver and gold bags are this.
2–3 plyMono-material PE
Every layer polyethylene, so the bag recycles as a soft plastic. Less barrier and a slightly softer hand; the sustainable choice where shelf life allows.
100–130 micronMono-material PP
Stiffer and clearer than PE, with better heat resistance. Suits a stand-up pouch that has to hold its shape on a shelf.
90–120 micronKraft-paper laminate
A paper outer over a film barrier. The natural look with a real barrier behind it; the paper takes only a matte, flat print.
Paper 60–80gsm + filmCompostable film
PLA and cellulose structures certified for industrial compost. Lower barrier, higher cost, and no home-compost claim unless the certificate says so.
60–90 micronLDPE mailer film
Co-extruded opaque film for shipping bags: tear- and puncture-resistant, weatherproof, and recyclable where soft plastics are collected.
60–80 micronNot sure which? Say what goes in it and where it is sold — the material follows from that. Our notes on recycled, recyclable and compostable cover which claims each stock can honestly carry.
- 01
Send what you have
A dimension, a photograph beside a ruler, or the product itself. No technical drawing needed — that part is ours.
- 02
We quote and draw
A price, a dieline and a date come back together. If a different build would suit the product better, that is in the reply too.
- 03
Approve the dieline
The flat drawing is yours to check: which panel is the front, where the folds fall, how deep the cavity really is.
- 04
Artwork on the dieline
You place your design on the flat we sent, or we place it for you, and you see a proof before anything goes to press.
- 05
A sample if you want one
A plain unprinted sample at the finished size shows fit and construction — the things a drawing cannot.
- 06
Cut, printed, shipped
The die is cut once and kept, so every reorder skips the tooling and goes straight to press at a lower unit price.
Format
Vector PDF or AI where possible. Raster artwork at 300dpi at final size, in CMYK.
Bleed
3 mm past every trim line, so a fraction of drift on the cutter never leaves a white edge.
Safe area
Keep type and anything important 4 mm inside the cut and away from every fold.
Color
Convert to CMYK before sending. Uncoated stock prints lighter; a spot color is the only exact match.
Fonts
Outline them or supply the files. A missing font substitutes silently and the proof will not match.
Barcodes
On a light, matte, unvarnished patch with the quiet zone clear — a code on gloss fails the scanner.
Not set up that way? Send it anyway — fixing a file is a short conversation, and we check every one before press. Our guide to preparing print files covers each point.
Film is finished in the lacquer and the ink, not with a laminate.
Matte lacquer
A soft, non-reflective face. Hides handling marks and the most-used finish on a premium pouch.
Gloss lacquer
Wet-looking color. Reads cheaper on some categories and exactly right on confectionery.
Spot matte on gloss
A matte shape on a gloss field, or the reverse. The film equivalent of spot UV.
Metallised effects
Print over the metal layer so a color picks up the shimmer, or lay white under it for a normal color.
Registered emboss
A raised texture pressed into the film. Rare, expensive, and unmistakable in the hand.
Kraft-paper face
A paper outer laminated to the barrier. Matte and flat by nature; no varnish needed.
Not sure which suits the shelf it sells from? Say where the product is sold and we suggest one — our notes on specialty finishes show them on real boxes.
Sizing a pouch by what goes in it, not by a bag size: mylar bags for freeze drying
Film packs are specified by fill, not by dimensions. Two products of the same weight can need very different bags, because density decides volume — whole coffee beans take far more room than the same weight of powder.
- Fill weight and density
- Give us both, or send the product. We size from the volume it actually occupies, settled.
- Lay-flat width
- Half the circumference of the finished bag. It is the number a converter works to, and we calculate it from your product.
- Headspace
- Enough film above the fill to seal cleanly and for the bag to stand. Too little and the seal traps product; too much and the pack looks underfilled.
- Gusset
- Bottom gusset depth sets how the bag stands; side gussets add volume without width. Both are chosen from the shelf, not the fill.
- Seal width
- 5–8 mm. Wider on liquids and creams, which contaminate a seal, and on anything that will be posted.
- Sample fill
- A plain bag at the finished size, filled from your line, is the only reliable check before print.
Not sure your numbers are right? Send the product dimensions rather than the box dimensions and we work the box out — the full method is in our guide to measuring for a box.
Interactive · five steps · no sign-up
Spec your Mylar Bags For Freeze Drying
Pick a shape, type a size, choose a film and a finish. The preview on the left redraws as you go, and the spec lands with us exactly as you set it.
Frequently asked questions
Got a question about mylar bags for freeze drying? The answers below cover what we get asked most. If yours is not here, send it with a brief, message us on WhatsApp, or call +1 503-461-4788 — we reply the same working day.
Is this a real foil bag or a metallized one?
Real foil. The barrier layer is aluminum foil laminated between polyester and polyethylene. Metallized film looks similar and is not adequate for long-term storage.
How long will freeze-dried food last in it?
With an oxygen absorber and a good seal, 10–25 years for most low-fat foods. Fatty foods are shorter, because the fat goes rancid before anything else.
What size do I need?
By volume, not weight — freeze-dried food is bulky and light. Tell us your freeze dryer model and we match the bag to one tray or a clean fraction of it.
Do I need oxygen absorbers?
Yes, for storage beyond a few months. The bag stops oxygen getting in; the absorber removes the oxygen that was already in the bag when you sealed it.
How do I seal it?
A flat-jaw impulse sealer, set for the PE layer. Seal within minutes of adding the absorber, with two inches of headspace so the jaws close flat.
Can it have a zipper?
Yes, above the heat seal, for a retail bag that is opened and closed. For pure storage a zipper is a small weak point and we leave it out.
Can I have a window?
Yes, but a window is a hole in the barrier. For storage bags we advise against it; for a retail snack bag with a short shelf life it is fine.
Is 7 mil better than 5?
Tougher, not better sealed. 7 mil resists punctures from sharp or dense products; the barrier is the foil layer and it is the same in both.
Are the bags food safe?
Yes. The inner PE layer is food-contact grade and the laminate is used for exactly this purpose across the food industry.
What is the minimum order?
100 bags per size. Printed mylar runs on a roll, so the set-up is in the plates rather than a die.
How long does production take?
It depends on the print and the quantity. We give a date with the quote rather than a number before we have seen the spec.
Will you send a sample?
An unprinted bag in your size and gauge, so you can fill it from a tray, seal it and check that it pulls hard before print.
Same range
