Custom Printed Silver Mylar Bags for Long-Life Dry Goods

What is a silver mylar bag?

A silver mylar bag is the plainest form of foil bag. The metallised or foil layer is left bare on the outside, so the bag looks like polished metal with no tint and no lacquer colour.

Two laminates carry the name. Metallised PET / PE has a vapour-thin aluminium coat and suits retail bags. PET / foil / PE has a solid aluminium layer and suits storage bags that need to hold for years.

Both arrive flat and open at the top. Stand up versions have a bottom gusset and a zipper. Flat versions are sealed on three sides and closed with a heat sealer after filling.

Who buys silver bags?

Companies that care more about what the film does than how it looks. Freeze-dried food producers, bakeries buying bulk bags, protein brands and seed merchants make up most orders.

Silver is one finish among several, and our range of foil mylar bags shows it beside gold, black and printed options.

• Freeze-dried fruit, meals and sweets sold for storage
• Bakeries packing flour blends and bread for freezing
• Coffee roasters selling 1 kg bulk bags to cafes
• Protein and supplement brands with plain bulk packs
• Seed companies and allotment societies
• Outdoor and expedition meal makers

Metallised PET or aluminium foil: which silver?

They look the same on the shelf. The difference shows over months, when a thin metallised layer lets a little more oxygen and moisture through than a solid foil layer does.

What size silver bag holds 1 kg?

A 1 kg stand up silver bag is often 200 × 300 mm with a 100 mm gusset for a product such as coffee beans or rice. Lighter products such as freeze-dried fruit or puffed cereal need a bigger bag for the same weight.

Flat bulk bags for 2.5 kg and 5 kg run 250 × 380 mm and 300 × 450 mm. They are sealed flat, so the length allows for the product settling and a wide top seal.

The fill weight alone does not settle the size. Tell us the product and we size the bag to its density, as explained in our guide to UK stand up pouch sizes.

Silver bags for freeze-dried and long-term food

Freeze-dried food is light, dry and keen to take moisture back from the air. A silver foil bag with an oxygen absorber sachet inside, heat sealed, is how most UK producers pack it.

The heat seal matters more than the zipper for storage. The zipper keeps the bag closed day to day, but the heat seal above it is what holds the barrier for years.

Thicker laminates with a solid foil layer suit the longest dates, and a nylon layer adds puncture resistance for sharp pieces. The options and pouch shapes are compared on our freeze-dried food bags page.

Zipper bags or heat seal only?

Retail bags get a zipper. The customer opens the bag at the tear notch, uses some and presses the zipper shut. A slider is an option on larger bags that are opened daily.

Bulk and storage bags are usually heat seal only. There is no need for a zipper on a 5 kg bag of flour that a bakery empties into a bin, and leaving it off lowers the price.

A valve is the third option, for roasted coffee only. Beans release gas for days after roasting, and a one-way valve lets it out without letting air in.

Printing on bare silver

Ink printed straight onto silver takes on a metallic sheen. Black looks sharp and is the most common one-colour choice. Red, blue and green look like coloured metal, which some brands like.

For true brand colours or a white panel, we lay down a white under-print first. The colours then print as they do on paper, with the silver showing only where the design leaves it bare.

Our designers set the artwork on the dieline and send a free proof. Bleed, seal areas and file formats are listed in our artwork guide for foil pouches.

How do you seal silver bags with an impulse sealer?

Most silver bags are filled by hand and closed with an impulse sealer. The routine takes seconds once the heat setting is right.

1. Fill the bag, keeping powder and crumbs off the top 30 mm.
2. Drop in an oxygen absorber if the product needs one and work fast from here.
3. Press the air out by hand or with a vacuum nozzle.
4. Seal once across the top with the bar set for the laminate thickness.
5. Hold the bag flat for a few seconds while the seal cools.
6. Check the seal is clear and continuous, then label and box.

Common mistakes with silver foil bags

Sealing over powder is the first. Protein or flour on the seal area leaves a channel, and the bag slowly lets air in. Fold the top over while filling or use a funnel.

Creasing the bag hard is the second. A sharp fold in a thin metallised film can open pinholes in the metal layer. Store empty bags flat and do not crush them in a drawer.

The third is using a thin bag for sharp or heavy products. Dried pasta and hard biscuits punch through a light laminate in transit. Ask for a thicker structure or a nylon layer.

Silver bags for bakeries and bread

Bakeries use large flat silver bags in two ways. Part-baked baguettes and rolls go into a foil bag for freezing, where the film keeps freezer smells and moisture off the bread.

Flour blends and bread mixes go into 2.5 kg and 5 kg bags for sale to home bakers and cafes. The silver face takes a simple black print with the mix name and the method.

Smaller bakery lines such as biscuits and cookies sit better in a retail zipper bag, which is a separate product on our cookie and biscuit bags page.

Ordering silver mylar bags

Send the product, the fill weight, stand up or flat, zipper or heat seal, and how many you need. Quantities are quoted per order, from £0.25 per unit, confirmed in writing.

Plain silver bags with no print are quoted the same way. Printed bags get a free design proof before anything is run.

Production takes 4–6 business days after approval, then free tracked UK delivery in 2–3 business days. Misprints or damage reported within 10 days with photos are reprinted or refunded. Use the quote request page for foil bags or send a WhatsApp.