Vacuum sealing mason jars used to mean a bulky bag machine and a hose attachment. It does not any more. A cordless jar sealer sits on the lid, pulls the air out in under a minute, and lives in a drawer.
This guide covers what the process actually does, what it suits, and the one thing people most often get wrong about it.
What is actually happening
Dry food does not really go off in the dramatic sense. It goes stale, and it goes rancid. Both are oxidation, which is oxygen slowly reacting with the fats and aromatic compounds in the food.
That is why coffee tastes flat after a fortnight, why wholemeal flour develops a bitter edge, and why nuts start tasting like the cupboard. Remove most of the oxygen and you slow all of it down, typically by a factor of three to five for dry pantry goods.
You also lock moisture out, which is what keeps crackers crisp and stops flour clumping, and you make the jar airtight against pantry moths and weevils.
What it works brilliantly for
- Coffee beans and ground coffee
- Nuts, seeds and trail mix
- Flour, especially wholemeal
- Rice, pasta, lentils, dried beans
- Rolled oats and cereal
- Dried herbs and spices
- Dried fruit
- Crackers, biscuits and anything that goes soft
- Popcorn kernels, sugar, protein powder
We have put rough before-and-after timeframes for most of these in how long vacuum sealed food actually lasts.
What it is not
This is the important part, and a lot of guides online are sloppy about it.
Vacuum sealing a jar is not canning. Canning is a heat process. It kills organisms in the jar and creates a shelf-stable preserve. Pulling air out of a jar at room temperature does neither of those things.
So a vacuum sealed jar of fresh or low-acid food is not safe to sit in a cupboard. If it needed refrigerating before, it needs refrigerating after. Sealing it just means it keeps better in the fridge.
It is also not for liquids. FoodVault is built for dry goods.
And it will not fix food that has already turned. Seal things fresh.
What you need
Three things, and you probably have one of them already.
Jars. Any standard mason jar works, in regular-mouth 70mm or wide-mouth 86mm. If you are starting from nothing, our glass mason jars come in 500ml and 750ml, in 4-packs.
Sealing lids. These are the reusable metal lids the sealer pulls against, in the same two sizes. Not sure which you need? See wide-mouth versus regular-mouth.
A sealer. The FoodVault Premium Electric Jar Sealer is cordless, charges over USB-C, and handles both jar sizes.
The process, briefly
Fill the jar leaving about 2cm at the top. Wipe the rim dry. Sit the lid flat. Press the sealer down until it clonks. Press the button and let it run 40 to 60 seconds. Wiggle it off side to side.
Then press the centre of the lid. Solid means sealed.
The full version, with pictures, is in how to use your jar sealer. If a jar is being stubborn, why your jar is not sealing covers the three usual causes.
Is it worth it?
The practical case is simple. If you buy coffee, nuts or flour in any quantity, you are currently throwing some of it out, or drinking and eating it well past its best. Sealing takes about a minute a jar and you do it once.
The pantry moth thing is the part nobody expects to care about until the first time it saves a whole shelf.