Custom Large Mylar Bags for Bulk Storage

Film Thickness and Bag Construction

Thickness is the biggest decision with large bags. Heavy contents press on the seams and corners, and sharp foods such as pasta, dried beans and kibble can puncture thin film when the bag is lifted. For anything over a few kilos we recommend a thicker laminate, measured in microns, with reinforced side seals. Thicker film also feels more substantial in the hand, which helps a premium bulk product justify its price.

Construction matters as much as thickness. A flat three-side-seal bag is the most economical shape and works well as a bucket liner. A bottom-gusseted stand-up bag sits upright on a shelf and is easier to fill. Side-gusseted bags behave like a coffee sack, with a square base that stacks neatly on a pallet. Each style can be supplied with a tear notch so the customer can open it cleanly without scissors. Matt, gloss and metallised films are shown in our film finishes compared guide.

Printing on Large Foil Bags

A large bag offers a big, flat print area that works almost like a poster. Brands selling bulk goods use it to tell people what is inside, how to store it once opened and how to reseal it. Clear storage instructions on the back panel reduce questions and returns, and a strong front panel helps the product get spotted in a stockroom or a farm shop.

We print in full colour onto the outer film. Silver foil shows through any area left unprinted, giving a metallic look, or we can lay a white base under the artwork so colours stay bright and true. Matt and gloss outer films change the feel considerably: matt reads as natural and premium, gloss is brighter and easier to wipe clean. Small text such as batch codes can be left blank for an inkjet or label applied at packing. Brands that change the harvest or the batch often add labels for changing batches to a base design.

Closures: Heat Seal, Zip or Both

For long-term storage the heat seal is what does the work. A zip alone will not keep oxygen out over months, so serious storage bags are always heat-sealed after filling, even if they also have a zip. The zip then becomes useful after first opening, letting the customer use part of the contents and close the bag again.

Retail customers buying large packs of oats or kibble appreciate a press-to-close zip because the bag is used over weeks. Bucket liners for storage often skip the zip entirely and rely on a wide seal area, since they are only opened when the bucket is put into use. If you are not sure which you need, tell us how the bag will be opened and used and we will recommend a closure. Bags that must stand on a shelf use the base on our gusseted mylar bags that stand page.

Notes on Food Contact and Storage

Food-contact grade film is available on request for bags that will hold food directly, and it is worth stating this clearly when you ask for a custom quote. We can also supply bags without a food-contact layer for non-food uses such as seed storage, documents or spare parts. Storage life depends on the food, the oxygen absorber, the seal quality and the conditions where the bag is kept, so we do not promise a particular shelf life.

Keep sealed bags in a cool, dry place away from rodents, which will chew through any film. Many people store large bags inside lidded buckets for exactly that reason. A dark cupboard, garage shelf or cellar with a steady temperature suits them far better than a loft that bakes in summer. Long-term food stores use our freeze dried food mylar bags with a thicker barrier.

Measure the Bucket, Not the Bag You Have Now

Large mylar bags are usually lining a bucket or standing in a sack, so the useful measurement is the container, not an old bag. Measure the inside diameter and height of the bucket, or the footprint of the shelf space, and tell us the fill weight and the product; rice, oats and kibble all take different volumes per kilo. Choose the film thickness by the weight and the sharpness of the contents, heavier for kibble and pasta, and the closure by use: a heat seal for long storage, a zip for a bag opened weekly, both for a bag that does each. Say if the bag needs to stand on a shelf, which calls for a gusset. Artwork covers the front, the back with ingredients and allergens, and the gusset, sent as vector files, and the free proof shows the print across all three. A custom quote comes by email within one working day with bags from £0.25 and minimums low and quoted per job. Production takes 4 to 7 working days after approval with free tracked UK mainland delivery. Mills packing 1.5 kg of flour use our flour mylar bags for 1.5 kg.