---
title: "Vacuum seal: what it means in cooking — Tiny Plates"
description: "Vacuum sealing removes air from a plastic bag and seals it shut. It slows freezer burn and spoilage but does not make food safe at room temperature."
url: "https://www.tinyplates.dev/glossary/vacuum-seal"
---

# Vacuum seal

Vacuum sealing removes air from a plastic bag and seals it shut. It slows freezer burn and spoilage but does not make food safe at room temperature.

Also called Vacuum pack, Vacuum packing, Vacuum sealing.

Vacuum sealing means sucking the air out of a plastic bag or container with a machine and sealing it shut. With little air, food dries out and goes stale more slowly, and mold and many bacteria grow more slowly. It is used to store food in the freezer and fridge, and to package food for [sous vide](https://www.tinyplates.dev/glossary/sous-vide)cooking.

## How to do it

1. Chill or freeze the food first. Never seal hot food.
2. Leave 5 to 8 cm (2 to 3 inches) of empty bag above the food so the machine can seal it.
3. Wipe the inside of the bag opening clean and dry. Grease, juice and crumbs stop it from sealing.
4. Freeze wet foods such as soup, stew or marinated meat flat in the bag first, or the machine will pull liquid into the seal.
5. [Flash freeze](https://www.tinyplates.dev/glossary/flash-freeze) soft food such as berries or bread first so it is not crushed.
6. Pad sharp bones with a folded piece of parchment so they do not pierce the bag.
7. Seal, check that the bag is tight against the food, and label it with the name and date.

## Why it works

Without air, fats oxidize more slowly and ice cannot leave the food's surface as easily, so vacuum-sealed food in the freezer suffers much less [freezer burn](https://www.tinyplates.dev/glossary/freezer-burn). But some dangerous bacteria grow without air. The bacterium that causes [botulism](https://www.tinyplates.dev/glossary/botulism) prefers airless conditions, and _Listeria_ grows at fridge temperatures with or without air.

## How to store it

Store vacuum-sealed food in exactly the same way as unsealed food. Raw meat and fish go in the fridge or freezer and keep their usual use by dates. Vacuum sealing helps quality, but it does not make food last much longer safely in the fridge.

For vacuum-packed fish sold frozen, the US FDA advises taking it out of the packaging, or opening the bag, before you thaw it.

## Common mistakes

* Treating vacuum-sealed food as [shelf-stable](https://www.tinyplates.dev/glossary/shelf-stable). It is not, unless it has also been canned or dried by a tested method.
* Sealing garlic, herbs or vegetables in oil and keeping them at room temperature.
* Sealing warm food, which stays in the danger zone longer.
* Using a soft bag in the fridge for weeks and trusting how the food looks.

## In recipes

"Vacuum-seal" in a recipe usually means bagging food for sous vide or for the freezer. A zip-top bag lowered into water to push the air out works for both. Vacuum sealing also helps food [marinate](https://www.tinyplates.dev/glossary/marinate) in a smaller amount of liquid, because the bag holds the marinade against the food.

## Related terms

* [Sous videSous vide cooks vacuum-sealed food in a water bath held at an exact temperature, so meat and fish cook evenly edge to edge and cannot overshoot.](https://www.tinyplates.dev/glossary/sous-vide)
* [Freezer burnFreezer burn is the dry, grayish, leathery patches on frozen food left exposed to air. It is safe to eat but tastes and feels worse, so trim it off.](https://www.tinyplates.dev/glossary/freezer-burn)
* [BotulismBotulism is a rare but serious illness caused by a toxin that grows in low-acid, airless food, such as badly home-canned vegetables or garlic in oil.](https://www.tinyplates.dev/glossary/botulism)
* [Flash freezeFlash freezing means freezing food in a single layer on a tray before bagging it, so berries, dumplings and cookie dough stay loose and easy to portion.](https://www.tinyplates.dev/glossary/flash-freeze)
* [MarinateTo marinate is to soak food in a seasoned liquid of acid, oil, salt and aromatics before cooking. Here are safe times and why longer is not always better.](https://www.tinyplates.dev/glossary/marinate)
* [Shelf-stableShelf-stable food can be stored unopened at room temperature, like canned goods, dried pasta and UHT milk. Many of them need the fridge once opened.](https://www.tinyplates.dev/glossary/shelf-stable)

[More in food safety and storage](https://www.tinyplates.dev/glossary/category/food-safety)[Every term from A to Z](https://www.tinyplates.dev/glossary)