How to Seal Canning Jars Without Boiling Water

By Charlotte King

The boiling process adds on to an already tedious canning process for some people. There’s no need to sterilize the jars then boil again for the canning process. Double boiling adds more time, headache, and work than is necessary. Yes, you will need to make sure your jars and lids are clean. However, it is possible to seal canning jars without boiling water to achieve the seal (pop), to ensure foods are safely preserved when you store them away for extended periods of time in the canning jar. So, what are some of your alternatives, as opposed to boiling? Consider trying out a few of the options in this guide on how to seal canning jars without boiling water!

The Upside Down Method

This is actually quite simple to do, and can be done with a variety of vegetables you are canning, or foods which you purify/liquid for canning purposes. We can use tomatoes as an example for this process. What you’ll do after your canning jars and lids are sterilized, is take the tomato puree out of the boiling pot (it should be hot, just pureed in order for this to work best).

With the hot puree you will

  • Pour the tomatoes (squash, pumpkin, etc) directly into the canning jars
  • Fill them leaving about 1 to 1.5 inches free headspace in each jar
  • Once filled you will place the lid around each of the jars
  • Now, tighten the lid and seal sufficiently to prevent spillage
  • At this point, you’ll turn each of the canning jars upside down and let them sit there

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.

Wax as a Sealant

A second option you might want to consider if you don’t want to boil canning jars for sealing purposes, is to use a sealing wax to seal the jars closed. What you will need for this process is

  • 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.

Again, this method might be best for something with a narrower opening (think of a soda or drinking bottle), but if properly done, with enough wax, can work with traditional canning jars and lids as well.

A Vacuum Pack Sealing Solution

Mason Jar

Another option to sealing canning jars without having to boil them is to use vacuum or suction sealing equipment for the job. For this process you’ll need the

  • Vacuum pack sealing equipment
  • The glass canning jar
  • Sealing equipment (lid)

The vacuum sealer is a special piece of equipment which is specifically intended for sealing lids, mason jars, and for canning purposes. Remember, as highlighted above, the jars should be sterilized properly before you place anything into the cans. And, it is advisable to also make sure you sterilize the lids to ensure the safest, cleanest canning jar when sealing foods.

With the equipment in place, you’re ready to go. Once your canning jars are completely cooled after the sterilization process, you’re ready to fill the jar. Remember, you want to leave sufficient headspace to ensure your canning jars pop (seal) entirely with this vacuum sealing process. It’s advisable to leave at least one inch of airspace, and with liquids, or jellies and jams, about 1.5 inches is a good clearance level for headspace in your jars.

If there are bubbles in the jar, using a non-metallic spoon is a good way to get them out. Remember, if there are bubbles in the jar, it’s not going to seal properly. This is also a good point to check the lids and the top of the canning jar, to ensure there aren’t any defects, if you haven’t already done so. To remove bubbles, run the spoon around the inside of the jar’s walls, and press down to compress the food you’re canning as much as possible. This should help reduce and eliminate the bubbles that are in the jar you’re sealing.

You can now prepare the vacuum equipment to seal your canning jars. You will first

  • Place the lid on the jar you are canning/sealing
  • You won’t place the lid ring on the jar at this point
  • Attach the hose to the vacuum pack equipment, using the jar sealer attachment
  • Place that attachment on top of the jar (lid)
  • Ensure tightness/firmness before you start the vacuum seal, to prevent the attachment head from falling off the lid

Turn the vacuum sealer on. Every sealer has different instructions, regarding timing, pressure, and other variables to ensure the tightest seal is achieved. Make sure to follow the instructions for the vacuuming equipment you’re using, to ensure the best results are achieved when sealing your canning jars. The machine will indicate when the jar is sealed, usually by shutting off on its own. At the end, you’ll also typically hear that pop sound that you want to hear when canning foods. You can now screw the ring on top of the jar lid for storing purposes.

Take the hose and the sealing equipment off of your jar. If it is still a bit warm (it shouldn’t be if you allowed it to sit long enough before vacuuming it), you might want to let the jar sit on a cooling rack or the counter until it cools off. Screw the ring tightly onto the jar. Store it in a cool dry place until you are ready to enjoy the foods you have canned.


There’s no way around the sterilization process, as it relates to cleaning the new canning jars and lids. You’ll want to boil them and follow proper steps (each canning manufacturer will include instructions for sterilization with your purchase) to ensure your jars and lids are safe for canning, and clean before you place any foods you want to can into the jars. Once sterilized, these are a few alternatives to the boiling water method. They shouldn’t take as long, are just as efficient, and are going to deliver the pop you want to hear, to ensure your jars are properly sealed, and safe for you to put away for longer term storage.

Be sure to check out our guide on how to preserve peppers!

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