Ready-to-Eat, Frozen or Instant Food: What Is the Difference?

In short: Ready-to-eat retort food is cooked, sealed in a foil pouch and sterilised at 121°C, so it keeps for about a year at room temperature and only needs heating. Frozen food is cooked or part-cooked and kept at −18°C, so it needs a freezer all the way to your plate. Instant food is dried, so you add hot water and wait. All three can be made without preservatives; they differ in storage, texture and how much work is left for you.

How are they made?

• Retort (ready-to-eat): the dish is cooked, sealed in a multi-layer foil pouch, then heated to 121°C under pressure until even the centre is sterile. Read what retort food is.
• Frozen: the dish is cooked, cooled and frozen; the cold stops anything growing, as long as it stays frozen.
• Instant (dehydrated or freeze-dried): the food is dried until almost no water is left; nothing can grow without water. You add it back when you eat.
• Canned: the same idea as retort, in a metal can instead of a pouch.

How do they compare?

Shelf lives vary by product: always read the date on the pack.

Do any of them need preservatives?

None of them has to. Retort food is sterile and sealed, frozen food is too cold for anything to grow, and dried food has no water for anything to grow in. Some products still add preservatives or other additives, so read the ingredient list; our guide to checking a ready-to-eat pack shows what to look for. Thakar Kitchen pouches have no preservatives and no added colours.

Which should you choose?

• A curry or dal that tastes home-cooked, with no fridge: retort pouch.
• You already have freezer space and shop often: frozen works well.
• Every gram counts, such as a trek: instant, dried food.

Our dishes are all retort pouches: Gujarati and North Indian curries, dals, khichdi and rice, from ₹125 a pouch. See every dish.

Questions people ask

Is ready-to-eat food the same as frozen food?

No. Ready-to-eat retort food is sterilised and sealed, so it keeps at room temperature; frozen food must stay frozen.

Does retort food need refrigeration?

Not before opening: it keeps about 12 months at room temperature. Once opened, eat it straight away, or refrigerate it and finish within 24 hours.

Is instant food the same as ready-to-eat?

Not quite. Instant food is dried and needs water added; ready-to-eat retort food is a finished dish that only needs heating.

Which keeps longest without a fridge?

Both retort pouches and dried instant food keep for months at room temperature; check the date on each pack.