A loud BANG in your pressure cooker is not what you want to hear.  Today I heard that sound.  Fortunately, I was just canning water (LOL...I know).  I was trying out a new canner, an All American pressure cooker which I'd cheaped out on all my life.  They're not cheap, BUT...I figured I better try it out and figure out what I'm doing.

Originally I was going to do green beans (easy stuff), but I thought I'd just test this thing out first.  (side note) When you bolt this puppy down, it makes some serious steam!  Holy cow!  It even looks skeery on the stove!  I pressured this badboy up with a quart of hot water inside just to test.  About 15 minutes into the steam, and before I got to pressure I heard this really loud..BANG!.  I was out in the garage when this happened.  The 15 lb jiggler hadn't even moved at this point, but...BANG!.  I figured the damn pot was gonna' blow up the joint; had the wife get the valuables and dogs (the ones we like anyway), and head for the hotel.  Damn joint was goin' sky high, near as I could tell.

I'll make this story short(er), (ala, TLDR style), and then fill in the blanks later.

TLDR version - No, the damn thing didn't blow up and fuck the whole joint up.  I was worried about that though.  It did, however, blow up the jar inside, a quart jar filled with hot water just as a test.  The freeking jar blew like a grenade inside that pot.  Dammit!  BUT, I didn't really know what happened...it just didn't sound good.

Well, 45 minutes later I cooled the pot down enough to open it (and it took a while).  Glass jar exploded inside the pot.  Hmmm...lesson learnd.  Glad I didn't have any food in there, or multiple jars in there, because that jar exploding would have exploded all the other jars.

Live and learn I guess.

I think that the manufacturing has changed on mason jars. The newer jars seem prone to catastrophic failure from nothing more than relatively minor temperature changes. Minor with respect to their expected tolerance.

I've lost three or four just pouring hot coffee into them (I use them for everything) and another two or three just quietly fractured while in the water bath. I now rinse my jars under warm water before pouring coffee if it's articularly cold.

I use the pressure cooker for decarboxylizing cannabis, then a lower temp for extracting into the oil. I have adapted my methods to prevent losing any batches. It can be recovered because of the oil and water, but that would be a total pain in the ass.

I bought an Instant Pot just because it has convenient settings to process cannabis and it can be done in individual mason jars start to finisb, but I love that thing for cooking now. I've got two gluten free ginger spice cakes in it right now. I don't really cook roasts any other way.

(11-03-2024, 08:36 PM)Ksihkehe Wrote: I think that the manufacturing has changed on mason jars. The newer jars seem prone to catastrophic failure from nothing more than relatively minor temperature changes. Minor with respect to their expected tolerance.

I've lost three or four just pouring hot coffee into them (I use them for everything) and another two or three just quietly fractured while in the water bath. I now rinse my jars under warm water before pouring coffee if it's articularly cold.

I use the pressure cooker for decarboxylizing cannabis, then a lower temp for extracting into the oil. I have adapted my methods to prevent losing any batches. It can be recovered because of the oil and water, but that would be a total pain in the ass.

I bought an Instant Pot just because it has convenient settings to process cannabis and it can be done in individual mason jars start to finisb, but I love that thing for cooking now. I've got two gluten free ginger spice cakes in it right now. I don't really cook roasts any other way.

I would love to know your process, this is something i would like to learn.

(11-03-2024, 08:36 PM)Ksihkehe Wrote: I think that the manufacturing has changed on mason jars. The newer jars seem prone to catastrophic failure from nothing more than relatively minor temperature changes. Minor with respect to their expected tolerance.

I've lost three or four just pouring hot coffee into them (I use them for everything) and another two or three just quietly fractured while in the water bath. I now rinse my jars under warm water before pouring coffee if it's articularly cold.

I use the pressure cooker for decarboxylizing cannabis, then a lower temp for extracting into the oil. I have adapted my methods to prevent losing any batches. It can be recovered because of the oil and water, but that would be a total pain in the ass.

I bought an Instant Pot just because it has convenient settings to process cannabis and it can be done in individual mason jars start to finisb, but I love that thing for cooking now. I've got two gluten free ginger spice cakes in it right now. I don't really cook roasts any other way.

I actually heated up the mason jar beforehand, and also filled it with the same temp (hot) water I had in the canner.  It didn't bust until the canner came up to pressure, so I'm not sure what happened.  Headspace was good (1", and I measured).  I think the fact I put the lid on with the warm water inside might have caused my 'finger tight' to be tighter than I thought, so the jar burst from internal pressure.  Not sure, but that's my theory.  Tomorrow I'm doing the beans come hell or high water, so I guess I'm gonna' find out.

Yeah, I've got an instant pot also, but up here they don't really get hot enough (hold enough pressure) for proper low acid canning.  Plus the new canner holds (18) jars.  We have another one, Fagor I think, but it's hard to tell what the temp inside is (i.e. it's just either sealed or not).

Not sure what 'decarboxylizing' is (but I should probably know, chemistry and all), but I'm pretty sure I understand what the oil extraction is.  When I was in college we used to get this stuff called 'hash oil' which, if I'm not mistaken, is pretty much the same thing.  Yeah, I don't think trying to separate the oil from water would be a whole lot of fun, but you gotta' do what you gotta' do to not lose your investment.

We use the instant pot for cooking, and the canners pretty much exclusively for canning.  Instant pot cooks a mean corned beef in about an hour or so!  Man, that stuff is great!  I buy 'em on sale after St. Paddy's day and stick them in the freezer.  Cook 'em up for cloak and dagger's and reubens.  Total bomb material!!

(11-03-2024, 10:17 PM)Theatreboy Wrote: I would love to know your process, this is something i would like to learn.

I'll be glad to share what I know, but honestly I'm kinda' new to pressure canning.  I've done it before by the seat of my pants and didn't die (so I guess that's a win), but not really with all the right gear like I've got now.  I've done tons of water bath canning (i.e. high acid), but this is kind of my first deep dive into low acid stuff like meat, chicken, seafood and other low acid foods.

There's quite a bit of good info out there on the web though.  Best advice I have initially is to stick with certified recipes.  The National Center for Home Food Preservation, and Ball Jar's website, (among others) have some great recipes and starter info.  Also the Amish Canning Cookbook, and Complete Guide to Pressure Canning, are some great books.  I highly recommend both (and have both).

Pressure canning is a bit more involved than water bath canning, and you kind of need to know what you're doing.  Modern canners are pretty safe, but you need to get the recipes right for long term storage else you can get sick.

For what it's wort when pressure canning you should always have at least two quart jars or four pint jars to prevent breakage.
I don't know why this is the 'rule' but that's what I was taught from my multi-generational canning family.

If I only had enough produce for one quart jar I was taught to add another quart jar of water.

Breakage happens as jars age; every few years I'd end up with a mess to clean up. Just par for the course.

I never, ever left my pressure canner unattended. Too many family horror stories of holes in the ceiling kept my eyes on the pot the whole time. lol

(11-04-2024, 01:38 AM)Nugget Wrote: For what it's wort when pressure canning you should always have at least two quart jars or four pint jars to prevent breakage.
I don't know why this is the 'rule' but that's what I was taught from my multi-generational canning family.

If I only had enough produce for one quart jar I was taught to add another quart jar of water.

Breakage happens as jars age; every few years I'd end up with a mess to clean up. Just par for the course.

I never, ever left my pressure canner unattended. Too many family horror stories of holes in the ceiling kept my eyes on the pot the whole time. lol

Interesting!  I did not know that.  And I'd had a canning lady tell me just the day before yesterday to do exactly what I did, but your observation makes sense.  I'm going with your advice in the future.

I'm doing beans today, so I'll have plenty more than just two jars in there.  Probably about (5-6).  Which brings up another question...can you go with anything less than a full first layer (i.e. (7) jars)?  Or, does it risk one falling and breaking?

Thanks for the input!  Very helpful.

(11-04-2024, 06:05 AM)FCD Wrote: Interesting!  I did not know that.  And I'd had a canning lady tell me just the day before yesterday to do exactly what I did, but your observation makes sense.  I'm going with your advice in the future.

I'm doing beans today, so I'll have plenty more than just two jars in there.  Probably about (5-6).  Which brings up another question...can you go with anything less than a full first layer (i.e. (7) jars)?  Or, does it risk one falling and breaking?

Thanks for the input!  Very helpful.

I only had a single layer canner but found this for you, which I would feel perfectly comfortable following:

Pressure Canning Two Layers
Pressure canning allows you to process multiple layers of jars simultaneously, making it a convenient and efficient way to preserve food. Here are some guidelines and tips for pressure canning two layers:

General Guidelines
Rack usage: Most pressure canners come with two racks. One rack goes under the first layer, and the second rack goes between the two layers of jars. If your canner doesn’t have two racks, you can use a wire rack or a plate to separate the layers.
Staggering: When stacking jars, stagger them to ensure even circulation of steam and water around each jar. This prevents hot spots and ensures proper processing.
Water level: Maintain the recommended water level in the canner, which is usually 2-3 inches deep. This ensures proper steam circulation and prevents jars from touching the bottom or sides of the canner.
Jar size and type: Use jars of the same size and type (e.g., pint or quart) to ensure even processing. Avoid mixing jar sizes or types within a single canning session.
Specific Tips
Presto canners: According to Presto’s instructions, you can double-stack jars without a second rack, but you must stagger the second layer of jars. Each top jar must be stacked upon two bottom jars.
Other canners: If your canner doesn’t have a specific guideline for double-stacking, use a wire rack or plate to separate the layers. This ensures proper steam circulation and prevents jars from touching each other.
Fill to capacity: Fill the canner to its recommended capacity to ensure even processing and prevent hot spots.
Processing time: Use the recommended processing time for the specific food being canned, regardless of the number of layers.
Examples from Search Results
A user with a Mirro 16 qt. canner reported that it can hold 10 pints or 7 quarts, with an extra rack to separate the layers.
Another user with a Presto 23 Qt. canner mentioned that it can hold 20 pints, but only 7 quarts, with an extra rack to separate the layers.
A user on Reddit shared their experience with double-stacking in a Presto canner, stating that they used the regular mouth Ball pint jars and staggered the second layer of jars.
By following these guidelines and tips, you can successfully pressure can two layers of jars, ensuring your food is properly preserved and safe to eat.

The reason you off-set them is for even heating of contents which is critical if you want to be absolutely sure your not going to be promoting the growth of botulism. It's a good idea to have your gage checked each year before canning season; it's free at your county extension office.
I canned one entire season with an inacurate gage, which cured me of not taking this viyal step; thankfully it was reading lower than it should so I actually over-processed everything. If it had ben reading higher I might not be telling you this.....

The FDA has canning guidelines on the internet that are really helpful if you don't have any generational canners to work with. Timing, altitude adjustment, properly maintained equipment and cleanliness are of the utmost importance.....and lots of elbow grease.

Lots of people who learn to pressure can use it for processing everything and turn their waterbath canner into a laundry soaking tub.  

Just don't leave your canner unattended-beans look terrible on the walls, floor and ceiling. 

P.S. I'm sure you know beans require a full inch of headspace, but I had to say it so I could sleep tonight. I'd rather be in your kitched ubtil you get your wings....

(11-04-2024, 07:02 AM)Nugget Wrote: I only had a single layer canner but found this for you, which I would feel perfectly comfortable following:

Pressure Canning Two Layers
Pressure canning allows you to process multiple layers of jars simultaneously, making it a convenient and efficient way to preserve food. Here are some guidelines and tips for pressure canning two layers:

General Guidelines
Rack usage: Most pressure canners come with two racks. One rack goes under the first layer, and the second rack goes between the two layers of jars. If your canner doesn’t have two racks, you can use a wire rack or a plate to separate the layers.
Staggering: When stacking jars, stagger them to ensure even circulation of steam and water around each jar. This prevents hot spots and ensures proper processing.
Water level: Maintain the recommended water level in the canner, which is usually 2-3 inches deep. This ensures proper steam circulation and prevents jars from touching the bottom or sides of the canner.
Jar size and type: Use jars of the same size and type (e.g., pint or quart) to ensure even processing. Avoid mixing jar sizes or types within a single canning session.
Specific Tips
Presto canners: According to Presto’s instructions, you can double-stack jars without a second rack, but you must stagger the second layer of jars. Each top jar must be stacked upon two bottom jars.
Other canners: If your canner doesn’t have a specific guideline for double-stacking, use a wire rack or plate to separate the layers. This ensures proper steam circulation and prevents jars from touching each other.
Fill to capacity: Fill the canner to its recommended capacity to ensure even processing and prevent hot spots.
Processing time: Use the recommended processing time for the specific food being canned, regardless of the number of layers.
Examples from Search Results
A user with a Mirro 16 qt. canner reported that it can hold 10 pints or 7 quarts, with an extra rack to separate the layers.
Another user with a Presto 23 Qt. canner mentioned that it can hold 20 pints, but only 7 quarts, with an extra rack to separate the layers.
A user on Reddit shared their experience with double-stacking in a Presto canner, stating that they used the regular mouth Ball pint jars and staggered the second layer of jars.
By following these guidelines and tips, you can successfully pressure can two layers of jars, ensuring your food is properly preserved and safe to eat.

The reason you off-set them is for even heating of contents which is critical if you want to be absolutely sure your not going to be promoting the growth of botulism. It's a good idea to have your gage checked each year before canning season; it's free at your county extension office.
I canned one entire season with an inacurate gage, which cured me of not taking this viyal step; thankfully it was reading lower than it should so I actually over-processed everything. If it had ben reading higher I might not be telling you this.....

The FDA has canning guidelines on the internet that are really helpful if you don't have any generational canners to work with. Timing, altitude adjustment, properly maintained equipment and cleanliness are of the utmost importance.....and lots of elbow grease.

Lots of people who learn to pressure can use it for processing everything and turn their waterbath canner into a laundry soaking tub.  

Just don't leave your canner unattended-beans look terrible on the walls, floor and ceiling. 

P.S. I'm sure you know beans require a full inch of headspace, but I had to say it so I could sleep tonight. I'd rather be in your kitched ubtil you get your wings....

Thanks! 

I wasn't actually wanting to go with 2 layers (I can in this cooker, but that wasn't really what I was asking).  What I meant to ask was if I can go with less than a full single layer?  I suppose I could fill up the excess space on layer #1 with water jars, but was just wondering if I could go without.  Hopefully that makes sense.

Oh, and no, I won't leave it unattended.  I'm too much of a micro-manager for that.  Last night I was watching every second, except for the 5 seconds I stepped away to grab something out of the garage (which is like 10 feet from the stove).  Of course, that's when the jar blew.  But there were no dramatic changes during those 5 seconds, it's just when the jar chose to blow.  You know, it's sort of like your phone ringing when you step into the restroom.  LOL!  (Seems like it happens every time).

Thanks again!

(11-04-2024, 01:21 PM)FCD Wrote: Thanks! 

I wasn't actually wanting to go with 2 layers (I can in this cooker, but that wasn't really what I was asking).  What I meant to ask was if I can go with less than a full single layer?  I suppose I could fill up the excess space on layer #1 with water jars, but was just wondering if I could go without.  Hopefully that makes sense.

Thanks again!

FDA canning site says you can do a partial canner batch with no mention of anything seperating the jars, unlike WB canning. I think it's because the water in a pressure cooker isn't doing a rolloing boil, but more of a slow simmer to heat the contents thoroughly. 
I checked a couple of other canning sites and they don't mention any sort of mechanical seperation either. I think you're fine; a full canner still has to have space between the jars for proper heat penetration. 
I tried to find the reason why canning just one jar would cause it to break but didn't have any luck. It probably has something to do with space/pressure/weather and what's on CNN, which is beyond my ability to figure out. 


I found it!
" In a pressure canner, the water level and the weight of the jars help to cushion and distribute the pressure. With only one jar, there may not be enough cushioning to absorb any minor vibrations or movements during processing, increasing the risk of breakage."