Long-term Food Storage on a Budget: Vacuum Sealing Canning Jars

Long shelf-life freeze-dried foods are ubiquitous in Prepper World.  They’re pretty good and have an enormous shelf life, but they’re also fairly pricey. A vacuum sealer & system for mason jars gives you the capability to store a wide variety of foods (or non-foods that must be kept dry) much more cheaply. 

It’s adaptable to multiple forms of stored foods, too. The same jars and lids (and oxygen absorbers for some materials) work for dehydrated and canned foods, as well as things that just need to be in a dry, low-oxygen environment to preserve their value.

This is what the cap-type vacuum sealers look like. The vacuum cap settles over the lid during sealing.

Salty and I talk about it in this podcast:

How vacuum sealed jars work

Oxidation reactions are responsible for a lot of changes in organic molecules.  They often change the molecules in stored food, causing degradation of taste and nutrition.  They also cause degradation of other materials, such as soft plastics and rubbers.  By sucking most of the air (and therefore oxygen) out of the jars, the stored materials undergo far fewer oxidation reactions.  Adding little packets of oxygen-absorbing chemicals enhances the effect, since not all the air is sucked out by the sealer.

After dehydration, veggies can be shaken compact in a mason jar, oxygen absorber added, and the
canning lid sealed by a vacuum sealer to extend the shelf life for years.

Sucking the air out also keeps the moisture low.  This slows other degradation reactions and discourages the growth of microbes.

Mason jar sealers have special lids that go on the jars; lids that have a rubberized ring to make an airtight seal.  You put the contents in the jar, maybe an oxygen absorber packet or two, and hook the jar and lid to a vacuum pump or into a chamber attached to a pump.  Run the pump a bit and most of the air will be sucked out, and if the ring and jar make a good seal, the partial vacuum inside the jar holds the lid down tight to prevent new air from leaking in when the pump is taken off.

How vacuum sealers do not work

Vacuum sealing is not like hot canning, which heats the food to kill microbes before sealing.  If you vacuum seal a jar full of something wet like tomato sauce, the microbes already in there (they’re everywhere, so being a clean cook doesn’t stop these guys from getting in) will quickly spoil the food.  Some of the microbes don’t need oxygen either.  

Sealers extend the shelf life of food that’s already microbe-proofed. They don’t themselves make the food microbe-proof.  How can you make food microbe-proof?

• Dehydration: This removes enough water that the microbes can’t grow
• Use naturally dehydrated foods: Pasta and other ‘dry goods’ can be sealed as they come
• Pressure canning:  These methods heat the food to kill the microbes. They use the same jars and lids as the vacuum sealers described in this article.  As the jars cool (sterile inside from the cooking), the contraction of the air provides the partial vacuum that holds the lid on and seals it.

Many different fruits and vegetables can be dehydrated and vacuum sealed. Nuts, pasta, and other naturally dry foods also have their shelf lives extended by vacuum sealing.

How to vacuum seal jars

Fill the jars, shaking contents down or otherwise packing them to get the most per jar and reduce how much air the pump must suck out.  Add an oxygen absorber packet or two if you wish to extend the shelf life further. 

Wipe the rim of the jar to get it fully clean and make sure it’s not marred by nicks or cracks.  Jars with flawed rims won’t seal; there’s no point in wasting your time trying.  Put a canning lid on top, making sure the rubberized seal is also clean and smooth. Put the suction cap on the lid/jar combo or put the jar in the suction chamber, depending on your model.  Let the pump do it’s thing and you’re done. At least when using the suction caps, you don’t use the screw-down rings that help keep the lids on during pressure canning.

Pull up on the lid gently.  The suction should hold it down.  Label and you’re done.

For best results, store your jars out of the light.  Light energy degrades molecules by different reactions; the vacuum sealing can’t stop that.  It’s also best to keep food at a cool, steady temperature.  A cool basement is ideal so long as it’s dry (not to rust the lids).

Jars can be reused so long as the rims are not nicked. Unused cartons make great lids to reduce light exposure to filled jars.

Upsides and downsides

• The same jars and lids work for pressure canning and vacuum sealing, so you can stack deep and use for what you need.
• Jars are re-usable so long as the jar mouths remain unblemished and the jars themselves are not cracked.  Don’t try to put vacuum pressure on a cracked vessel!
• Lids are not reliably reusable.  They often get bent or the seals otherwise damaged when the seal is broken to open the jar.  I stock lots.
• Other small items that must be kept dry and/or in a low oxygen environment (perhaps to keep rubber parts pliable) can also be vacuum sealed in jars.
• Some reusable lids made of plastic exist.  I’ve just started testing them, so can’t speak yet to how well they work.

• 

  Metal canning lids aren’t reliably reusable, so I stock lots. They work for both pressure canning and vacuum sealing jars.

  

  These are the plastic, reusable canning lids. Pricey, but …reusable. I’ve just gotten to start testing them.