When Canning How do jars seal?

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asked Nov 15, 2020 in Cooking by Wjendyfromhol (5,390 points)
When Canning How do jars seal?

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answered Nov 18, 2020 by Kingpetch (3,570 points)

When canning foods in canning Jars or Mason jars the lids have a seal around them that seals through a vacuum process.

When you heat the canning jars up a vacuum is created in the jar which pulls the air out of the canning jar and seals the canning jar lid.

The vacuum draws the lid down and keeps it there until you open it.

You can tell when a canning jar or mason jar is sealed by tapping the top of the lid with a spoon and if the canning jar or mason jar is sealed it will make a ringing high pitched sound but if the canning jar or mason jar lid is not sealed properly then it will make a dull sound.

To seal a Mason Jar without boiling it you can use a mason jar vacuum sealer that seals the mason jars without heat.

Or place the Mason Jars upside down after removing them from the boiling water and while they are still hot you can seal them by putting them upside down.

Allow each of the jars to sit upside down for 5 to 15 minutes. Once this time elapses, your canning jars are going to be extremely hot, so it’s advisable to wear gloves when flipping them right side up.

When you flip all jars back over, you’ll allow them to sit on a counter or cooling rack, for a minimum of 30 minutes. If you allow them to sit overnight, this is going to help further vacuum seal the cans.

This process utilizes pressure while the jars are upside down.

A vacuum seal is created by all the pressure of the pureed liquid sitting directly on the canning lids (which are a metal/aluminum blend). Since this material is conducive to high temperatures, it will vacuum tighter, the longer you allow the canning jars to remain upside down.

With the canning jars sitting right side up, you’ll usually hear them pop after several minutes.

The heat which was created around the lid creates a vacuum, which suctions out any pressure or air, and allows the canning jars to safely seal. Depending on the foods you’ve pureed, placed in the canning jar, you can typically place these in the pantry for a year or more with some foods.

You do have to seal mason jars or canning jars if you want to preserve the food in the mason jars.

If you don't seal the mason jars properly then the food will go bad in the mason jars.

Sealing the mason jars prevents bacteria from growing in the food and makes the food in the mason jars last longer.

You can seal the mason jars with boiling water or by using a mason jar vacuum sealer which is pretty cheap to buy.

Another way to seal mason jars is Wax Sealant.

If you don’t want to boil canning jars for sealing purposes you can use a sealing wax to seal the jars closed. What you will need for this process are.

  • The ceramic sealing wax dish
  • Scissors
  • Filament tape
  • Kitchen lighter
  • Bottle sealing wax

Before you begin the sealing process, it’s important to ensure the canning jars and seal are properly sterilized. With this sealing method, you might want to use canning jars with a thinner opening (consider a drinking bottle), however, you can use this method with any glass canning jar for foods you want to preserve, and consume at a later time.

You’ll start by placing the ceramic wax sealing dish on a table, counter, or level surface.

Some sealing dishes have a spot for you to place a candle directly below it, where you’d place a candle or your lighter, to melt the wax from below. If your sealing dish doesn’t have this, make sure you leave some clearance space below the dish, so that you can place the candle or lighter there, in order to heat the wax which will be used to seal the can.

Once the candle is sitting below the sealing dish you’ll light it.

Once the candle is lit, you’ll take the granular wax you purchased (granular wax is available in many colors, it doesn’t really matter which you choose), and place the wax onto your ceramic sealing dish. Start by placing a small amount to let it melt.

Once melted, you’ll add on more wax, and the melted/heated wax at the bottom, will help in heating and melting the additional layers of sealing wax you add on top of the dish.

It might take anywhere from 20 to 30 minutes for the wax to melt down entirely, depending on how much you place in the wax dish, so be patient, and don’t try to speed along the process.

Doing so won’t allow you to create the right texture for the wax to seal the cans.

Place food or liquid into the canning jar you want to seal. Twist the cap or lid on tightly, and take the filament tape you purchased to wrap around the jar’s lid.

Dip the jar’s lid into the melted wax solution for several seconds.

Remove it and let the excess melted wax drip off. Once the wax barrier is hardened on the jar, you can apply another coat of melted wax, and follow the same process, allowing the second layer to harden and seal off the jar.

Allow the wax sufficient time to harden before putting the canning jar away.

If you just seal the mason jar by hand then it may not seal out all the bacteria.

But for something that will not spoil then just sealing the mason jar by hand will be good enough.

To seal mason jars or canning jars with boiling water just place the mason jar into a pot of boiling water for a few minutes.

The boiling water will seal the mason jar.

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