Short answer: for a 12-month retail shelf, specify a foil laminate — PET/AL/PE is the standard. For 6–9 months with a premium metallic look, PET/VMPET/PE is enough. Clear PET/PE suits short-cycle whole bean where the product has to be visible. Kraft is a print-surface choice, not a barrier choice: a kraft bag is only as protective as the liner behind the paper.
A coffee laminate is three jobs stacked together
Every flexible coffee pack is built from webs that each do one thing:
- The print web. PET, BOPP or paper. It carries the artwork, gives mechanical strength and takes the heat of the filling line.
- The barrier web. Aluminium foil (typically 7–9 µm) for maximum protection; metallized PET for a good, cheaper compromise; EVOH coextrusion where clarity or recyclability is required.
- The sealant. PE or CPP, the layer that actually melts and bonds to itself to close the bag.
The barrier web decides the shelf life. The sealant decides whether the bag holds — and on dark roasts, the sealant is where most failures start.
What "barrier" means in numbers
Two measurements do most of the work when you compare structures:
- OTR — oxygen transmission rate, usually quoted in cm³/m²/day at 23 °C and 50 % RH. Oxygen is what stales coffee.
- MVTR — moisture vapour transmission rate, in g/m²/day. Moisture loss flattens aroma and changes the grind.
For coffee, high-barrier constructions are generally specified below 1 cm³/m²/day OTR. Published values for common constructions fall roughly in the ranges below — the exact figure depends on the converter, film gauge and test conditions, so always ask for the test report for the structure you are buying rather than relying on a datasheet typical.
The five structures buyers actually choose
| Structure & typical use | OTR (indicative) | Shelf life | Trade-offs |
|---|---|---|---|
| PET/AL/PE Retail ground and whole bean, export | < 0.5 | 9–12+ months | Highest protection; not transparent; foil blocks metal detection and is not recyclable in mono streams |
| PET/VMPET/PE Specialty retail, premium look | ~1–3 | 6–9 months | Metallized layer can crack at sharp folds; glossy appearance |
| PET/PE Short-cycle whole bean, product visible | Tens to ~100+ | 1–3 months | Cheapest and clearest; poor oxygen barrier |
| Kraft/PE Natural / eco positioning | High (PE only) | 4–8 weeks typically | Paper aesthetic, weak barrier; needs a foil or metallized liner for real shelf life |
| Kraft/AL/PE or MDO-PE/PE Premium eco; mono-material programs | Very low / moderate | 9–12 months / 6–9 months | Kraft/foil looks natural but is not recyclable; mono-PE is recyclable but gives up barrier |
Match the structure to the coffee, not the other way round
Roast level. Darker roasts release more CO₂ and, more importantly, put oil on the bean surface. That oil migrates into the seal area, and a seal contaminated with oil bonds weakly. If you pack dark roasts, specify an oil-resistant sealant and check seal strength on the actual product, not on an empty bag.
Grind. Ground coffee has far more surface area than whole bean: it degasses faster and oxidises faster. Ground always wants the higher-barrier structure plus a valve, and nitrogen flushing helps more here than anywhere else.
Shelf-life target. This is the number that should drive the quote. Tell the supplier "9 months at 25 °C" and the structure follows; tell them "a coffee bag" and you will get whatever is cheapest.
Channel. Retail distribution with a distributor's warehouse in between is not the same as selling direct within three weeks. The longer the route, the more the barrier is worth paying for.
The details that decide whether the bag holds
- Total thickness. Three-ply coffee laminates commonly run about 100–140 µm. Thinner is not automatically worse, but it is less forgiving on the filling line.
- Zipper compatibility. A zipper is welded into the sealant side; the sealant has to be compatible with the zipper resin or the weld peels.
- Valve patch. The film under the valve needs enough stiffness to keep the membrane seated. Very thin clear structures can be a poor host for a valve.
- Filling temperature. Hot-fill and high-speed form-fill-seal lines put different demands on the sealant than manual filling.
What to write on the purchase order
Most quality disputes in flexible packaging trace back to a vague PO. Specify, at minimum:
- Full structure with gauges, e.g. PET 12 / AL 9 / PE 80
- OTR target and test conditions
- Bag dimensions and fill weight, with tolerances
- Seal strength minimum
- Valve type and position (if any), zipper type (if any)
- Print method and colour standard
- Food-contact declaration requirement
Testing before you commit to a run
Ask for, or run: an OTR/MVTR report on the exact structure; a seal-strength test on filled bags at production temperature; a drop test on a filled carton; and a shelf-life check — hold samples at elevated temperature for two to four weeks and taste against a frozen control. Coffee is a sensory product; the only test that matters is whether it still tastes right at month nine.
What we supply
Xiangyi Packaging runs PET/AL/PE, PET/VMPET/PE and kraft laminates for coffee, with or without a one-way valve, in stand-up and 8-side seal formats. Minimum order is 10,000 pieces for multi-layer barrier pouches and 5,000 for simpler printed bags; plain stock starts at 1,000. Our systems are certified to ISO 9001:2015 and ISO 22000:2018, and PE/PP food-contact grades reference 21 CFR 177.1520, with declarations and migration reports available on request.
Typical coffee structures run 100–130 µm in total. The exact gauge and structure for your order are confirmed on the specification sheet, and the OTR and moisture test report for the structure is available on request.
Next step: send the roast level, grind, fill weight and the shelf life you need to promise your customers. We will propose a structure, quote it against one cheaper alternative, and tell you honestly where the cheaper one will fail. Custom coffee packaging · High-barrier structures
Frequently asked questions
Is PET/AL/PE always the best choice?
It is the highest-barrier choice, not always the best one. It is opaque, it is not recyclable in mono streams, and it costs more. For a roaster selling whole bean locally within a month, a clear or metallized structure costs less and performs adequately.
Can kraft bags keep coffee fresh?
Only with the right liner. Kraft/PE gives you weeks, not months. Kraft/AL/PE gives you real shelf life, but the pack is then a foil laminate with a paper face — do not market it as plastic-free.
Do I need a different structure for ground coffee?
Yes, generally the higher-barrier one, plus a valve. Ground coffee degasses and oxidises faster, so the same film that protects whole bean for nine months may only protect ground for six.
What is the recyclable option?
Mono-PE structures (often with an MDO-PE print web) are the mainstream recyclable route today. Expect higher OTR and a shorter shelf life — typically 6–9 months rather than 12.