It is not unusual for something as long-processed as fish to bubble for quite some time. However, in your case continuing to bubble is probably a result of leaving the fish in the canner, where the environment is quite hot.

I do have some concerns. First, are you speaking of pints? Secondly, when you say you turned off the heat and left, did you wait for the pressure to return to zero and remove the weight or did you merely leave the canner as is?

Be aware that leaving food in a pressure canner beyond the stipulated time does present a food safety risk. I don't know the degree of risk as opposed to, say, turning off the canner and leaving it overnight, but I do know long sitting at warm temperatures can be a problem. In that case leaving the weight on might be helpful as the temperature likely remained quite high.

Carol

If you left them in the canner for 6 hours they may not be safe to eat. There is a thermal loving bacteria that can grow. You need to remove after the pressure is a zero, with just an extra 10 min wait time. Then, you should wait 24 hours before you remove the rings before you wash the jars and rings.
You said "cooker". Is it indeed a cooker or a canner ? What size is it ? If it will only hold pints and not at least 4 qt. jars it is not a canner and not safe for processing food in.
Another thing, if you leave that canner with the lid on for 6 hours you may get a reverse vacuum and then your canner it toast ! You would have to throw away the canner. Seriously, this really does happen sometimes.
I am also wondering why you have so little tuna in the jars ? Seems you have way too much liquid in the jars.
Not being critical, just trying to figure out if what you did was safe.

linda lou wrote:

"There is a thermal loving bacteria that can grow"

What bacteria is that? I'm assuming this is some sort of bacteria that survives through the pressure canning process, but then multiplies in a warm environment?

Just Google 'thermophilic bacteria' for all kinds of info. They are called heat lovers since they can survive at cold temps and even under pressure but then thrive in hotter temps. Per Google they include Chloroflexus aurantiacus, Deinococcus radiodurans, Thermus aquaticus, etc.

Dave

The pint jars were not completely full, as this was a practice run in order to see if we have a preference to oil vs water, and baked vs raw packed. I did just turn off the cooker and leave it as is for 6 hours. the interesting thing is that the only jars that bubbled were the oil filled ones.

It is a 23qt. pressure canner, I didn't think it was important to remove the jars at a certain time. The NCHFP is clear that cooling shouldn't be rushed, but doesn't make it clear that there is such thing as cooling too slow.
Thanks for the replies! I will look into thermophilic bacteria.

From what I've read, one of the potential problems is that it can take a long time before the jars actually seal, and that is the point that the "stuff" can get in there and start growing.

They do eventually cool down enough and seal, but you don't want them sitting around for a few hours in a hot canner before that happens.

Canners like the Presto have a little pin that pops up under pressure, and drops down when pressre is normalized. When it's down, it is like having the weight removed, and no vacumn can form in the canner as it's no longer sealed.

I sure wish the AA has something like that. I'm canning out doors, and it's cooler out and in even just a few minutes, that AA lid can get sucked down pretty fast. My gauge is off and never gets to zero, so I'm always watching to see if it's still moving, or if it appears to have stopped. I keep a rubber mallet on hand to get the lid to release.

Presto canners still get reverse vacuum. It happened to my friend in her Presto.

Ok, that explains the small amount of fish in the jars.

That is right about the jars not sealing and then sitting in a hot temperature. Also, even if jars are in the pantry and the temp. is above 90,the food can spoil in the sealed jars.

That is awful about needing a rubber mallet !

After doing 12 more "test" jars of chicken and venison, It appears that the bubbling is normal as home canning jars cool. It's been awhile since I've been in a physics class, but I think since a vacuum is created in the jars, the boiling point lowers, and the liquid is boiling as the jar cools (even though it is cool enough to handle,) which threw me off at first. Maybe the oil ones cool slower than water, and that's why only the oil ones were bubbling when I took them out?

Based on a little google research, most thermophilic bacteria seem to grow in 40-70C or 104-158F.
Based on that, most won't grow during the actual processing of the jars, but could (if that type of bacteria was present) grow during the pressurizing (heating), and cooling stages. Since these types of bacteria supposedly are present in food, I will make sure not to take any longer than necessary in the heat up, or cooling down stages of canning. Also not storing in warm temps should help too.

That is also why you want to leave air space between jars on the counter while cooling and why covering with a towel (which some do) is not a good idea.

Carol

Learned something new today by reading this thread. I kept wondering why no one was objecting to the use of oil because I thought oil was a no-no except in a few tested recipes. So I went to the source...NCHFP...and discovered that tuna can definitely be canned in oil. So now my question is why it works?

Here is a link that might be useful: NCHFP how to can tuna

You mean why canning in oil works? Because the tuna falls into the except in a few tested recipes category.

Due to the high risk, I doubt there's anything more carefully tested than the processing time for fish, with or without added oil.

Also, I thought I would clarify that raw-pack of tuna as the OP mentioned doing is safe. Instructions are available in other reliable Extension documents (like Oregon State University Extension Canning Seafood).

The reason the NCHFP doesn't provide instructions is because tuna, particularly, can be excessively strong in flavor if raw-packed. We do raw-pack tuna but we trim very very well and just accept the fact that there's more waste.

Carol

Here is a link that might be useful: OSU Canning Seafood

I raw pack my tuna every year too (per WSU and Oregon State edu), and even without adding oil or water, the jars are 1/2 to 2/3s full of oil/liquid when they come out of the canner anyway :)

I meticulously remove anything dark or resembling dark. The fish has a stronger smell than commercially canned tuna before draining opened jars, but I don't find the taste strong - or I wouldn't be going to the trouble to can it.

Many years ago, my MIL used to take fish to a self help cannery, bake and cut, pack the cans, top with olive oil, leave the rest to the cannery to finish and return to her.

IMO, it was a pretty Ho-Hum product, not significantly different that what can be purchased. It wasn't until I tasted raw packed tuna that I began doing my own, a couple of decades ago. There are about 55#s of jar ready trimmed and individually wrapped loins in my freezer right now, waiting for the right weekend :)
(The day I picked it up, we were just coming to the end of 49 days of guests from Europe, there was not a foreseeable good canning day.)

cb, if you are still reading....raw packed fish, nothing added, will come out of the canner after 100 min. processing, pressure reduction and 10 min to rest with significant bubbling in the jars for several additional minutes. I haven't had reason to time it but 25 minutes would not surprise me.

yes after doing a couple more batches of different things, I am seeing that bubling is normal as the vacuum increases and the can cools. what a good forum this is BTW!

I had a quart jar of okra to do this bubbling for hours and hours. This was after it was out on the cabinet cooling. It was still bubbling in the middle of it the next evening! I've NEVER had one do it for that long! It was sealed and everything. My daughter told me, Momma that thing is STILL bubbling (this was the next evening) in the center of it. I left it sitting off to itself to watch it and it stayed sealed. I thought it was really weird.
This is so interesting by the way. When I saw your topic I just knew by bubbling you meant that it was ruined until I started reading on then I realized it must have done the same thing my okra did which I found really weird.

Next time I can tuna I am adding vegetable broth. The commercial cans have it in there. I can't see an issue with just vegetable broth since it now says to use water in jars of tuna.

Just posted on Cooking forum - should have come here first and done a search. All of this information is very helpful. I will be doing Tuna when the weather cools -and- when my new gasket and pressure plug arrive.

DL

Just processed a batch of raw tuna with oil like I've been doing for 15 years or so and this is the first time I can recall the tuna bubbling for so long. It's been about 1-1/2 hours now. The jars get some oil on the outside so I always scrub them down after they seal and before I label them. The jars are plenty cool enough to handle, but still bubbling. I'd have been a bit concerned if I hadn't found this site.

BTW I find home canned tuna is much milder and even sweeter than store bought.