Shelf life is one of the first questions every food brand asks when choosing packaging. Whether your product stays fresh for two weeks or twelve months depends largely on the barrier properties of the film you choose. This guide explains the key barriers, the common material structures and how to match them to your product.
What does “barrier” mean in flexible packaging?
A barrier is how well a packaging film stops something from passing through it. For food, the three most important barriers are:
- Oxygen barrier (OTR) — oxygen causes oxidation, rancid oils, color change and mold. Measured as oxygen transmission rate; lower is better.
- Moisture barrier (WVTR) — water vapour makes crisp products soft and powders cake. Measured as water vapour transmission rate; lower is better.
- Light barrier — UV and visible light break down vitamins, fats and natural colors, especially in coffee, nuts and supplements.
Aroma barrier and grease resistance also matter for coffee, spices and pet food.
Common barrier materials compared
- Aluminum foil (AL) — the highest barrier to oxygen, moisture and light. Best for long shelf life, but not see-through and harder to recycle.
- Metallized PET (VMPET) — a thin metal layer gives a good barrier at lower cost and weight than foil. Popular for snacks and coffee.
- Nylon (NY / PA) — excellent puncture resistance and a good oxygen barrier. Used for vacuum bags, frozen food and retort pouches.
- EVOH — a very high oxygen barrier while staying transparent. Ideal when you want a clear window and long shelf life.
- PET and BOPP — strong, printable outer layers with a moderate barrier.
- PE and CPP — sealing layers on the inside. RCPP is used for high-temperature retort.
Match the barrier to your product
| Product | Main risk | Typical structure |
|---|---|---|
| Roasted coffee | Oxygen, aroma loss | PET / AL / PE with one-way valve |
| Snacks & nuts | Oxygen, moisture, light (rancidity) | BOPP / VMPET / PE |
| Ready meals (retort) | Bacteria, oxygen, high heat | PET / NY / AL / RCPP |
| Frozen food | Puncture, cold cracking | NY / PE or PET / PE |
| Powders & supplements | Moisture, caking | PET / AL / PE or PET / VMPET / PE |
| Fresh bread | Short shelf life, condensation | Mono PE or OPP with micro-perforation |
Clear window or full barrier?
A window lets customers see the product, but it lowers the barrier in that area. If you need both visibility and long shelf life, consider a transparent high-barrier film such as EVOH or AlOx/SiOx-coated PET instead of plain PET/PE.
What about recyclable and compostable options?
Mono-material PE structures with a thin EVOH layer can offer a good oxygen barrier while remaining recyclable in PE streams. Compostable films (PLA/PBAT, cellulose) usually have a lower moisture barrier, so they suit dry products with shorter shelf lives. Tell us your target shelf life and market, and we will recommend the best balance.
How to choose: a quick checklist
- What is the target shelf life (weeks, months, 1 year+)?
- Is the product dry, oily, liquid or frozen?
- Will it be vacuum packed, nitrogen flushed, boiled or retorted?
- Do you need a transparent window?
- Does your market require recyclable or compostable packaging?
Not sure which structure fits your product? Our engineers will suggest a material and send samples so you can run your own shelf-life tests. See our retort & vacuum pouches, stand-up pouches and coffee bags, or request a free quote.