Last updated: 9 July 2026•6 min read•By Antilia Tec Pack R&D
What is retort packaging?
Retort packaging is a flexible or semi-rigid pack — most often a retort pouch — that is filled, hermetically sealed, and then sterilised at high temperature and pressure so the food inside becomes shelf-stable without refrigeration. It delivers the long ambient shelf life of a can in a lighter, faster-heating, easier-to-open format.
How does the retort process work?
After the product is filled and the pouch is sealed, the packs are loaded into a retort (an industrial autoclave) and heated with pressurised steam or hot water, typically to 121°C for standard retort or up to 135°C for high-temperature short-time processing. The heat destroys spoilage organisms and their spores; the pressure counteracts the internal pressure of the pack so the seals hold. The pack must survive the full cycle without delaminating or losing seal integrity.
What is a retort pouch made of?
A retort pouch is a multi-layer laminate built to survive sterilisation and hold a high barrier for the product's full ambient shelf life. Typical structures are PET/Aluminium/CPP or PA(nylon)/Aluminium/CPP: an outer polyester for print and heat resistance, an aluminium foil (or high-barrier alternative) for the oxygen and light barrier, and a cast-polypropylene (CPP) sealant that stays strong at retort temperatures. Nylon adds puncture and flex-crack resistance.
Retort vs canning vs aseptic packaging
| Retort pouch | Metal can | Aseptic | |
|---|---|---|---|
| Sterilised in-pack | Yes (121–135°C) | Yes | No — product and pack sterilised separately |
| Cook time | Short — thin pack heats fast | Long — thick can | Very short (flash) |
| Weight & shipping | Light, low volume | Heavy | Light |
| Best for | Ready meals, curries, gravies, seafood, pet food | Traditional canned foods | Liquids, dairy, juices |
Compared with canning, retort pouches heat faster (better flavour and texture), weigh far less, and ship flat. They are the format of choice for shelf-stable ready-to-eat meals, gravies, sauces, seafood and wet pet food.
Which BARRIXA™ grade should retort packaging use?
Retort products need both heat resistance and the highest barrier, so Antilia specifies the BARRIXA™ ULTRA grade (OTR ≤ 0.08 cc/m²/day, WVTR ≤ 0.06 g/m²/day) in retort-rated structures. See the Retortable Pouch for the material options, or the glossary definition of retort.
Design your retort pouch
Rated for 121°C or 135°C — built for your product.
Tell us your recipe, fill weight and process and our R&D team will recommend the laminate and BARRIXA™ grade.
Talk to an Expert →Frequently asked questions
What temperature is retort packaging processed at?
Standard retort is around 121°C; high-temperature short-time processing runs up to 135°C. Both are carried out under pressure in a retort (autoclave) so the seals hold.
How is a retort pouch different from a normal pouch?
A retort pouch uses heat-resistant laminate structures (for example PET/Al/CPP or PA/Al/CPP) with a high-temperature CPP sealant that survives sterilisation without delamination or seal failure — ordinary pouches cannot.
How long do retort-packed foods last?
Retort-sterilised, hermetically sealed products are typically shelf-stable at ambient temperature for 12–24 months, depending on the recipe and barrier structure.
Which BARRIXA grade is used for retort?
BARRIXA™ ULTRA (OTR ≤ 0.08 cc/m²/day, WVTR ≤ 0.06 g/m²/day) in retort-rated structures, for maximum barrier plus heat resistance.