Canning 101: Why You Should Bubble Your Jars

bubbling the relish

Often, when you read a recipe for pickled vegetables, chutneys, relishes or whole fruit preserved in a syrup solution, you’ll come across a phrase that says something along the lines of, “bubble your jars thoroughly.” For new canners, this is often a confusing statement. What exactly is the recipe asking you to do and why do you need to do it?

When a recipe instructs you to bubble your jars, it is telling you to take either a plastic or wooden utensil (I really like that long, skinny spatula you see in the picture above. However, a wooden chopstick or a plastic knife work well too) and insert it into your jar. You use that utensil to wiggle your product around in order to release any trapped air bubbles. You do this after you’ve packed your jars and topped them with your brine or syrup (or after a chunky sauce/chutney/relish has been ladled in).

The reason you want to choose a tool that is made of either plastic or wood is that they will not scratch up the insides of your jars. Metal utensils can leave very small scars behind that end up shortening the lifespan of your jars. When working with glass, it’s always a good idea to do what you can to prevent breakage. This is one of those things.

The reason it’s important to rid your jars of trapped air is that in canning, the empty space to product ratio needs to balanced carefully. You need to have enough air in the jar so that after processing, the escaping heat can pull the oxygen out of the jar and create the vacuum seal. However, too much air and you find that some of your product is left sticking out of the preserving liquid, leaving it prone to discoloration and the development of off-flavors.

Additionally, if you leave those air bubbles trapped somewhere in the middle of the jar, they may try to escape during processing and can end up pushing some of your liquid out of the jar, leaving you with even less of your precious brine or syrup.

If you’ve had that loss of liquid happen to you in a previous canning attempt, don’t despair! As long as the seal is good and firm, the contents of the jar are still fine. You will want to move them up to the front of the consumption queue though, as they will not keep as long.

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76 Responses to Canning 101: Why You Should Bubble Your Jars

  1. 51

    […] Ladle hot liquid over peppers leaving 1/4 inch headspace. Remove air bubbles. […]

  2. 52
    nay says:

    I canned chow chow for the first time and I used twice as much cabbage as it called for. From 1 qt to 2 qts, all other ingredients were accurate. My relish hardly had any brine, go figure, but I did manage to get 4 pints, all with proper head space. It’s just that it was rather thick without a lot of liquid. Are they still safe to eat considering chopped vegetables to vinegar ratio will be off? Don’t want to kill the family.

    • 52.1
      JG says:

      It’s never a good idea to alter the dry weight-to-acid ratio of a recipe. Although you may get away with it, a 100% inaccuracy such as doubling the dry weight for the same amount of brine is, IMHO very risky at best.

  3. 53
    Joy Kennedy says:

    Your website is wonderful!! I have canned before, but it has been awhile. I’m really enthusiastic about canning again and have canned some pickled okra and sweet pickles. I had some questions about the head space in the jars, but all my questions have been answered here. Your answers have given me the confidence to continue canning. Peaches and chow chow are next on my list followed by some homemade veggie soup!! thanks so much for this wonderful information!!

  4. 54
    diana v. says:

    at the end of my water bath process, 2 of my jars were floating above water level when I removed the lid to my pot. ?
    I have never had this happen to me. I was canning apple slices in a very light sugar/cinnamon syrup.
    any ideas?
    I’m still waiting to see if they seal, but I think I will just eat those 2 right away…:)

  5. 55
    Kathy says:

    I got this great idea to pack a lot of fruit into each jar, which is easy to do when you hot pack. Now, after losing some liquid when I processed the peaches and pears…..there is very little liquid in the jars. I found one site that said to toss it if you lose 1/2 of your liquid. It appears I have lost that much in many of the jars but everything in the jar is nice and wet, just not much liquid sloshing around. Will my fruit be ok? Do I really have to toss it? Should I just open everything and re-process it or freeze it?

  6. 56
    Teresa says:

    How do I can if I only have 6 pints instead of a full 9?

    • 56.1
      Marisa says:

      Do you mean that your canner isn’t full? You put the jars you have in, make sure they’re fully submerged in the water and process. You don’t have to run a full canner load every time.

  7. 57
    Gerri says:

    Is it alright to use a stainless steel spatula with a silicon tip to exhaust air bubbles out of the jars during canning???

    • 57.1
      Marisa says:

      As long as the metal doesn’t come into contact with the interior of the jars, it should be fine. The reason we recommend using plastic or wooden tools to remove the bubbles is simply to prevent scratching the interior of the jars. That kind of scratching can lead to jar breakage.

  8. 58
    James says:

    Here is a related question: I have made jam and jelly from fruit that I previously froze several times and only, in this one instance, did my jam come out with millions of little air bubbles. In fact, I followed the same recipe the week before (from the Ball book of canning & preserving) and my jam had little to no bubbles.
    In this one instance, at the beginning of the cooking process, the peaches were not completely room temperature soft when I starting the jam making process. I think that the change in state from frozen slush to boiling liquid created air pockets that I trapped upon adding the sugar. I have given most of the jars to family with suggestions to open, refrigerate, and use quickly (since it’s bourbon peach jam, I am assuming that won’t be hard for most of my family to do), but I am curious if anyone reading this has made a batch like this and tried to keep it on the shelf and/or how the jam kept with time (?).
    Lemon juice was added to balance the pH, all other aspects of Ball recipe followed strictly.
    Processed this batch, as I always do, in a boiling water canner for 10 minutes, cooled on wire rack, washed and heated jars before filling, used seals heated in almost simmering water, etc.


  1. Peter Piper’s Got Nothin’ on Me! | Crazy Crayons - July 31, 2014

    […] Ladle hot liquid over peppers leaving 1/4 inch headspace. Remove air bubbles. […]

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