We don't sell packaging. We sell shelf life.
Article · Packaging Explained
Barrier film selection comes down to four inputs: how sensitive your product is to oxygen and moisture, the shelf life you need to claim, the conditions the pack will actually travel through, and the format. Only the last is about the film. The other three are about your product and your supply chain.
Get it wrong in one direction and product fails in transit. Get it wrong in the other and you pay, on every single order, for protection the product never used.
This guide gives a five-step procedure that ends in an OTR and WVTR figure you can put on a purchase order — plus the honest version of what over-specifying costs.
OTR is the oxygen transmission rate — how much oxygen passes through a film in a day, in cc/m²/day, tested to ASTM D3985 or ISO 15105-2. WVTR is the water vapour transmission rate, in g/m²/day, tested to ASTM F1249 or ISO 15106. Lower numbers mean slower ingress, which means longer shelf life.
Both are measured under stated conditions, conventionally 23 °C for OTR at 0% relative humidity. Barrier film selection starts here, because comparing two quotes means comparing figures measured the same way — a number without its test conditions is not a specification. Our OTR & WVTR guide covers the measurement side in detail.
What these numbers do not tell you is your shelf life. They describe the film, not the system. Pack size, fill weight, headspace and route conditions all sit between the film's rating and the date on your label.
Because the properties that make a polymer a good barrier are not the properties that make it sealable or tough. According to Labthink's material data, polyethylene runs above 5000 cc/m²/day on oxygen while EVOH coextrusions come in below 2 — a difference of more than three orders of magnitude.
| Material | OTR (cc/m²/day) | WVTR (g/m²/day) | Role in the laminate |
|---|---|---|---|
| Polyethylene (PE) | > 5000 | ~10 | Sealant and food contact |
| Oriented nylon (ONy) | 50–200 | — | Toughness, puncture resistance |
| EVOH coextruded | < 2 | — | Oxygen barrier core |
| BOPP | — | 0.5–1.5 | Moisture barrier, printability |
| Metallised PET | 0.1–1 | 0.1–0.5 | Oxygen, moisture and light barrier |
| Aluminium foil laminate | ~0 | ~0 | Absolute barrier |
Read the first row against the third. Polyethylene seals reliably and stops almost no oxygen. EVOH stops oxygen and cannot seal or survive handling on its own. Neither is a package. Laminating them — with tie layers to bond dissimilar polymers — is how you get all the properties at once.
One caveat the datasheet number hides: EVOH's oxygen barrier is measured dry, and it weakens as humidity rises — OTR can climb several-fold at high relative humidity. That is why EVOH is buried between hydrophobic layers, and why high-moisture or retort products often lean on foil, metallised or AlOx/SiOx barriers instead, which hold up under wet conditions.
This is also why thickness is the wrong lever. Doubling the polyethylene doubles cost and stiffness and barely moves the oxygen number, because the sealant was never doing the barrier work. What changes OTR is the barrier layer.
For most products one of the two dominates, and it is usually obvious from how the product fails. If it goes rancid, stale or loses aroma, oxygen is limiting. If it goes soft, sticky, clumped or mouldy, moisture is limiting. Specify against the dominant one first, then check the other is adequate.
| Product type | Fails by | Limiting factor |
|---|---|---|
| Roasted coffee, nuts, high-fat snacks | Rancidity, aroma loss | Oxygen |
| Spices, tea | Colour and aroma loss | Oxygen |
| Crisps, biscuits, crackers, wafers | Loss of crispness | Moisture |
| Milk powder, instant drinks, premix | Clumping, caking | Moisture |
| Dry fruits, confectionery | Texture change, sugar bloom | Moisture |
| Cheese, dairy, processed foods | Both — oxidation and moisture change | Both |
| Retort meals, baby food | Oxidation, sterility | Oxygen, near-absolute |
| Fresh produce | Respiration, not permeation | Neither — needs MAP |
Two useful checks. Crisp products are moisture-limited even when they are also fatty, because texture fails before rancidity is detectable. And products with water activity already close to a mould threshold have almost no moisture headroom, so their WVTR requirement is tighter than their oxygen one.
Fresh produce is the exception that catches people out. Respiring product consumes oxygen and produces CO₂ and ethylene inside the pack, so a very high barrier actively makes things worse. That is a controlled-permeability problem, not a high-barrier one.
Barrier film selection runs in five steps, in order. Each one narrows the specification, and only the last is a conversation with a supplier.
Step 3 is the one most often skipped, and it is where export claims fail. According to FSSAI's import requirements, food must retain not less than 60% of its shelf life at customs clearance, which means a product with a six-month claim must clear customs with about 3.6 months left. Transit, clearance and buyer inventory all consume the claim before the product reaches a shelf — so the same product sold for export usually needs a tier above its domestic specification.
Match the tier to the limiting factor and the shelf life, not to the most protection available. The BARRIXA™ tiers are built so you can buy the barrier your product needs rather than the barrier that sounds safest.
| Tier | OTR (cc/m²/day) | WVTR (g/m²/day) | Choose it when |
|---|---|---|---|
| SMART | < 0.50 | < 5.00 | Dry foods, bakery, confectionery, MAP produce, economy retail — short to medium domestic shelf life |
| PRO | < 0.20 | < 0.20 | Snacks, spices, coffee, tea, hot-fill, frozen — the working default for most exported dry goods |
| PRIME | < 0.10 | < 0.10 | Dairy, processed foods, pharmaceuticals, nutraceuticals — where both factors are tight |
| ULTRA | < 0.08 | < 0.06 | Retort, vacuum, premium coffee, baby food — and anywhere you are replacing aluminium foil |
For context on the scale: according to industry guidance on transmission rates, the threshold for oxygen-sensitive products such as roasted nuts and ground coffee is under 1 cc/m²/day. Every tier above sits well inside that, which is what makes long export cycles possible — but it also means the difference between tiers is a real cost decision, not a rounding error.
It costs on every order, permanently. This is the part of barrier film selection nobody selling film wants to raise: a higher tier is a more complex laminate — more layers, more material, more process steps — so the premium is not a one-off. Over three years of repeat orders it compounds into a number worth taking seriously.
There are non-cash costs too, and they are easier to miss:
Under-specifying costs more when it goes wrong — a rejected consignment, a failed date claim, a shelf life study to run again. But "always buy the highest tier" is not risk management. It is paying an insurance premium on a risk you never measured.
Aluminium foil laminates are effectively an absolute barrier — around zero on both OTR and WVTR according to Labthink's material data — and nothing else matches them. The question is whether your product needs absolute, or just very good, because foil brings real constraints with it.
Choose foil when the product is extremely oxygen-sensitive with a long ambient claim, when light exclusion must be total, and when microwaveability and recyclability are not requirements.
Choose foil-free when you need microwave capability, when recyclability or mono-material direction matters commercially, or when you need the pack to pass inline metal detection. Modern nano-engineered foil-free films reach near-aluminium performance — BARRIXA™ ULTRA sits below 0.08 cc/m²/day on oxygen — which puts most previously foil-only applications within reach.
The honest position: if you genuinely need zero, foil is still the answer. For most products, "very close to zero" is indistinguishable in shelf life terms and buys you options that foil forecloses.
With a shelf life study in the actual pack. Barrier figures predict; a storage trial confirms. Run the product in the exact structure you intend to buy, at pull points across and beyond your target date, and check it against pre-agreed end-of-life criteria.
Two rules that save the most money here. First, do not run the study in a sample pouch and then order a different structure — the study only supports the pack it was run in. Second, if you later change the film to save cost, the study no longer supports your date and needs repeating. Our guide on how to validate a shelf life claim covers the protocol.
Start with the limiting factor — oxygen if the product goes rancid or loses aroma, moisture if it goes soft or clumps. Then set your required shelf life, describe the real transit route, and state the pack format and size. Those four inputs convert into an OTR and WVTR specification.
It depends on how your product fails. Coffee, nuts and spices are oxygen-limited. Crisps, biscuits and powders are moisture-limited. Dairy and processed foods need both. Specify against the dominant factor first, then confirm the other is adequate for your shelf life.
Because thickness usually means more sealant, and the sealant was never providing the barrier. Polyethylene runs above 5000 cc/m²/day on oxygen while an EVOH core is below 2. Adding polyethylene adds cost and stiffness without meaningfully improving the oxygen number.
Only if you need an absolute barrier. Foil laminates are near zero on both OTR and WVTR, but they cannot be microwaved, complicate recycling and can interfere with metal detection. Foil-free high-barrier structures now reach below 0.08 cc/m²/day, which covers most previously foil-only applications.
Usually one tier higher for the same product. Transit time, port clearance and buyer inventory all consume shelf life before the product reaches a shelf, and FSSAI requires imported food to retain at least 60% of its shelf life at customs clearance.
