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Leaking Jars in Pressure Canner

Posted by chadg Ohio (My Page) on
Sun, Aug 8, 10 at 17:16

I processed a bushel of tomatoes this weekend and had two jars leak in the canner. One jar leaked a lot was only 3/4 full when i pulled it out.

I left 1/2" of head space in the quart jars.

I put the tomatoes into the jars and pressed them down until the juice was covering. Then used a chopstick to get bubbles out.

Do i need more head space to avoid this? Any other ideas why they would leak. I have a gas stove not electric.

Any ideas let me know, Thanks!

Follow-Up Postings:

RE: Leaking Jars in Pressure Canner

Hi Chad - lost liquid in jars can be cause by a couple of things - siphoning or the food absorbs some of the liquid.

Siphoning in a PC and in a BWB have somewhat different causes. PC it is fluctuating pressures during processing. I assume you used the BWB? In BWB it is usually bands were not screwed on tight enough, air bubbles in the jars, jars were overpacked and boiled over, or a bad seal (bad lik or chip in jar rim).

Then there is the absorbed liquid problem if you use raw (cold) pack, which it sounds like you did. In that case leave a 1" headspace.

If I had to guess, since it was only a couple of jars, odds are you had a couple of jars that were over-packed and/or bands weren't screwed down enough on those jars.

Hope this helps.


RE: Leaking Jars in Pressure Canner

BWB? Boiling water bath? I used a pressure canner.

Siphoning? This means the contents siphons out of the can into the canner? I am learning your lingo.

I was cold packing the tomatoes. I never cooked the tomatoes before putting them in the jars.

My 11 year old was in charge of packing and i would check them and put lids and rings on. So the two jars that did "siphon" where probably over packed.

I was the one in charge of the lids and rings. I learned my lesson a few year back of not over tightening rings. The lids would "pinch". So since then i tighten, but don't over tighten.

I am not disappointed. I got 2 jars that siphoned out of 19. The seals seem fine so far. I am just wondering why and you helped me with my question.

Over packing, not tight enough rings. I will start there to prevent this.


RE: Leaking Jars in Pressure Canner

Ah! Then since you pressure canned them (I must have missed that info in your first post ;), the most common cause is what is called "siphoning" (more discussions here about it the search will pull up if interested) and is due to fluctuation in pressure during processing and not waiting the 10 mins between removing the weight and removing the lid.

Even tiny adjustments of the heat once pressure has been reached causes internal changes in the pressure and liquid and ingredients in the jars is literally sucked out of the jars. Solution is once the required pressure is achieved, don't touch the stove knob. It is a more common problem for folks using a gauge canner as they try to nail that 10 lbs. mark. Weight-gauge canners it is less of a problem.

Of course over-packing and lose bands also contribute to the problem. Next time consider use hot pack method as it is generally the preferred method and gives better results. You have the choices of whole or halved packed in water, whole or halved packed in tomato juice, or crushed with no added liquid. Different processing times for each but all of them still have the acidification requirement even when pressure canned.


Here is a link that might be useful: NCHFP - Canning Tomatoes

RE: Leaking Jars in Pressure Canner

I think the crushed tomato recipe makes the best final product. Don't leave more headspace than called for. Headspace is important. Too much headspace and not all the air will be expelled from the jars.
Yes, but sure you add the bottled lemon juice or citric acid even if pressure canning. Otherwise your tomatoes will not be considered safe to eat.
With a dial gauge canner you use 11 lb. pressure, not 10. That is for a weighted gauge canner only.
It is important to wait the extra 10 min. in the canner, as was said.

RE: Leaking Jars in Pressure Canner

chadg, Forgive me for hijacking your thread, but Linda's mentioning of headspace got me really worried.

I just finished my first time ever canning and I left more than an inch of headspace. I was nervous about having enough head space and didn't know that you can have too much (I don't remember reading that anywhere). My husband isn't sure home canning is safe so I'm being really cautious. Now it looks like I made a safety mistake anyway.

My tomatoes were hot packed, processed at 15 lbs for 15 minutes (pints), and all are sealed. The head space is about 1 3/8.
How will I know if my food is safe?

This whole canning thing has been nerve racking. And I'm a trained laboratory scientist!

RE: Leaking Jars in Pressure Canner


FMI "and not waiting the 10 mins between removing the weight and removing the lid."

After you relieve the pressure, why does it matter how long you leave the lid on?

RE: Leaking Jars in Pressure Canner

It allows the product to cool down enough that the pressure in the jars isn't as extreme. Even though when it cools, the air pressure will be negative, creating a vacuum and sealing the lid, when it's just finished processing the opposite is true. The contents in the jar are hot......liquid and gas expands when it's heated and the room air is cold. The liquid inside the jars attempts to reach equilibrium with the room air and the pressure is such it forces it out from under the seal. It can 'dirty' the seal enough with food products after siphoning that when the jars cool and the vacuum should be created sealing won't.

RE: Leaking Jars in Pressure Canner

thanks calliope

RE: Leaking Jars in Pressure Canner

potterhead2: you should be fine with a little larger head space as long as you got a good seal.

More head space means it can take longer to evacuate the air out and get a good seal. If there is more air you can also get discoloration on the top layer of the tomatoes.

I grew up canning with my grandma. She would can everything. She only used boiling water bath (just from lack of knowledge back then). No one ever got sick even with low acid things like beans. Of course i know better (and dont advise what my grandma did) and i use my pressure canner on low acid foods and follow the recipe and advice of the books i have read.

You just need to be aware of the proper techniques and respect the idea that canning can be dangerous if you don't follow those techniques.

Keep reading and learning about canning. It is very safe if you take the time to learn more about it.

Congrats on your first batch! Wait until winter when the fresh local produce is not available. It is awesome to pop open a can of your tomatoes in December and enjoy your labor.

RE: Leaking Jars in Pressure Canner

I used hot pack method with a half inch of head space. when I took them out of water bath some juice leaked out. the jars still sealed. did I fill them to much and are they safely sealed?

RE: Leaking Jars in Pressure Canner

If you're talking about hot pack tomatoes, 1/2" headspace is what's recommended. It's possible you were a bit too aggressive packing the tomatoes in and in those jars there was some expansion of product, causing the liquid to expel.

Did you remove the lid of the canner and turn off the heat when processing time was done and allow the jars to sit untouched for 5 minutes before removing from the water? This reduces the likelihood of siphoning of liquid from the jars.

If the jars have a good strong seal, they're still OK, but I would place those jars at the front of the shelf and use them first. Due to product between the lid and the rim, it's possible the seal may break at some point.


RE: Leaking Jars in Pressure Canner

Yeah year before last when I did my first pressure canning I took the jars out of the water too soon and they siphoned to. They sealed and stayed sealed but I sure was worried they were messed up.

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