Canning jars

[Muse]

They aren't Pyrex, but I'm wondering if you can pour boiling hot fluid (e.g. water) into cold canning jars and safely assume they won't crack the way ordinary glass jars often do.

 

[highland145]

Don't canners boil the jars 1st anyway to kill bacteria?


Calling Dr. P.

 

[skyking]

I always preheat things a bit.
One method is to run the oven on warm. Use a gloved hand to retrieve the jar and then ladle in the hot contents.

 

[Muse]

I always preheat things a bit.
One method is to run the oven on warm. Use a gloved hand to retrieve the jar and then ladle in the hot contents.

What I've been doing for years is basically par-boil them for a few minutes before ladling in contents. However, I wonder how necessary that is. If I'm going to process in pressure cooker the bacteria will be taken care of that way. Question is, it seems, is there a chance the jars will crack due to the thermal stress?

Sometimes I just want to pour boiling hot liquid in a jar which I want to refrigerate for a week or so. I sometimes pour half in, let the glass heat up, then pour in the rest. Is it necessary to wait? Is the glass they use resistant to cracking from thermal stress, more so that ordinary jars?

 

[skyking]

I have no idea. My spider sense says don't do it.

 

[Ns1]

i would not make that assumption

 

[highland145]

Still....wouldn't you want to kill any bacteria in the jar 1st? Bacteria + your stock = waste.

Or am I missing something?

 

[MongGrel]

I'd preheat Ball/Mason jars, if I remember things right there would be jars heating up in kettles of water.

They could probably take it fine, but still.

Even used to make some equipment for Ball Brothers in my younger days, Muncie, Indiana right near Ball State University when I worked at Yorktown Tool and Die.

Went through my apprenticeship there, Yorktown was kinda of a little suburb of Muncie,

Sad that place is shuttered down these days, was a large toolshop, along with the Borg Warner Gear that was near it and many others.

Many women in the family have been doing it for generations, usually involves pressure cookers and things too from my past experience.

I was usually involved in the processing part of it when I was younger, rather than the actually canning.

 

[skyking]

Still....wouldn't you want to kill any bacteria in the jar 1st? Bacteria + your stock = waste.

Or am I missing something?

I wash in a hot bath of antibacterial soap, rinse it hot and then they get the oven treatment. I'd go right from the bath but sometimes I'm a little busy stirring stuff.
We canned 36 qt of peaches, 16 pints of pear preserves, 8 pints of smoked salmon, 30qts of tomatoes. 40 half pints of various jams. Made a few gallons of freezer jam too. It had been years since we had canned and we went a little wild.

 

[Muse]

Still....wouldn't you want to kill any bacteria in the jar 1st? Bacteria + your stock = waste.

Or am I missing something?

No, you're correct, as a general thing, assuming I want to keep it more than a couple of days. I don't always, but usually do. :thumbsup:

 

[Muse]

I wash in a hot bath of antibacterial soap, rinse it hot and then they get the oven treatment. I'd go right from the bath but sometimes I'm a little busy stirring stuff.
We canned 36 qt of peaches, 16 pints of pear preserves, 8 pints of smoked salmon, 30qts of tomatoes. 40 half pints of various jams. Made a few gallons of freezer jam too. It had been years since we had canned and we went a little wild.

OMG, that's a canning frenzy!

I canned peaches here until the dwarf peach trees died, first one, then the other. Canned peaches were really nice to have, I had them in ~12 oz. jars. They are not cloying like the canned peaches you see in the super markets, which are so sweet. I didn't skin mine, I like the texture of unskinned canned peaches, and they weren't toooooo sweet. I don't buy canned peaches anymore. I wouldn't like them after having enjoyed my home canned ones.

I have canned jams of various kinds (have literally gallons stored in jars from 8 oz. to quarts) and have been canning my tomatoes every year, done this for many many years. I have never ever processed any of that and never had a problem. As long as the jars were heated in ~1" of boiling water in a covered pot and the contents were ladled in boiling hot and the jars quickly covered (and I immediately turn them upside down for a couple of minutes to insure that any fungus spores are killed), the jars keep for literally decades. What I have done is gone to adding citric acid to my tomato concoctions just to insure that they are acid enough to insure against botulism growth. However, I never knowingly had a problem with that before going the citric acid route. I notice no difference in the product, I just want to be safe.

This year, for the first time, I started canning my kabocha squash (Japanese pumpkin). I have canned about 11 gallons of soup in quart jars (and around 4 quarts of straight cooked kabocha). Those, I have processed in my large pressure cooker (4 jars at a time) at 10-11 lb. pressure for 90 minutes, according to instructions. The soup is fabulous.

Now, not processing is very dangerous if you are canning certain things. Tomatoes (in particular if you add citric acid) are so acid that botulism isn't a concern. With the amount of sugar I add to my fruit when I make jam, nothing except maybe a fungus gets interested. Heated over 160 degrees, fungi cease to be a problem, so in my experience processing is just too fussy to bother with. I have jams on my shelf that are from the last century that taste fine when opened. I even have tomato sauces from ~1999 that are fine!

 

[GagHalfrunt]

They aren't Pyrex, but I'm wondering if you can pour boiling hot fluid (e.g. water) into cold canning jars and safely assume they won't crack the way ordinary glass jars often do.

Define "cold". Canning jars can take boiling, they're usually boiled prior to use to kill bacteria. You can safely pour boiling liquids into room temperature jars and they won't crack. If for some odd reason you store your jars in the freezer and pour boiling liquids into them while they're still frozen you're on your own. That could be enough of a temperature differential to crack them.

 

[tsiunltdus]

The jars should be sterilized prior to adding the food your canning. Yes the contents of the jars is canned in a pressure canner or boiling bath but it still is the best and safest measure prior to canning. Sterilize those jars.

 

[Ns1]

OMG, that's a canning frenzy!

I canned peaches here until the dwarf peach trees died, first one, then the other. Canned peaches were really nice to have, I had them in ~12 oz. jars. They are not cloying like the canned peaches you see in the super markets, which are so sweet. I didn't skin mine, I like the texture of unskinned canned peaches, and they weren't toooooo sweet. I don't buy canned peaches anymore. I wouldn't like them after having enjoyed my home canned ones.

I have canned jams of various kinds (have literally gallons stored in jars from 8 oz. to quarts) and have been canning my tomatoes every year, done this for many many years. I have never ever processed any of that and never had a problem. As long as the jars were heated in ~1" of boiling water in a covered pot and the contents were ladled in boiling hot and the jars quickly covered (and I immediately turn them upside down for a couple of minutes to insure that any fungus spores are killed), the jars keep for literally decades. What I have done is gone to adding citric acid to my tomato concoctions just to insure that they are acid enough to insure against botulism growth. However, I never knowingly had a problem with that before going the citric acid route. I notice no difference in the product, I just want to be safe.

This year, for the first time, I started canning my kabocha squash (Japanese pumpkin). I have canned about 11 gallons of soup in quart jars (and around 4 quarts of straight cooked kabocha). Those, I have processed in my large pressure cooker (4 jars at a time) at 10-11 lb. pressure for 90 minutes, according to instructions. The soup is fabulous.

Now, not processing is very dangerous if you are canning certain things. Tomatoes (in particular if you add citric acid) are so acid that botulism isn't a concern. With the amount of sugar I add to my fruit when I make jam, nothing except maybe a fungus gets interested. Heated over 160 degrees, fungi cease to be a problem, so in my experience processing is just too fussy to bother with. I have jams on my shelf that are from the last century that taste fine when opened. I even have tomato sauces from ~1999 that are fine!

is this your compound? you are clearly prepping for the apocalypse.

 

[DrPizza]

I've read that the jars are supposed to be warm when filling.

That said, for me, I'm always adding boiling hot food (or at least boiling liquid in the case of syrup for some fruits) into the sanitized jars that are sitting on kitchen towels. Then putting the lid and ring on the jar, and submerging into already boiling water. Never had a problem, regardless of the starting temperature of the jar.

I usually sanitize the jars in the dishwasher - sanitize cycle, plus my tap water is 160 degrees. But, by the time I get to the 3rd or 4th batch, the jars are approaching room temperature. Sometimes, I sanitize the jars by boiling them for a few minutes. But, I sanitize all of the jars prior to processing any of them - the water in the water bath has to be deeper, because the water is going to fill the volume of the jar while sanitizing. Whereas when canning, the jars are going to displace a lot of water, raising the water level. Usually, if the jars are cooler, I'll turn them on their side and submerge them for a few seconds each to warm the jars. Not because I'm worrying about cracking, but so that after filling them, the cool jars aren't cooling the contents, leading to insufficient processing. Note: do NOT submerge jars by rapidly plunging them straight down into the water. As the water rapidly fills, it'll lead to a large splash from the center of the jar as the water rushing in from one side meets the water rushing in from the other side. Boiling water in the face isn't pleasant. If you forget this, you'll learn the hard way.

 

[Muse]

is this your compound? you are clearly prepping for the apocalypse.

No, that's not my compound. However, you are correct in that I am preparing for the apocalypse, at least in part. I can partly because my crops are so big, if I don't a lot of stuff will spoil, unless I give it away, which I sometimes do. But the apocalypse stuff is just that I'm adequately prepared for a large earthquake. I do live ~1.5 miles from what's regarded as the most dangerous earthquake fault in the USA, the Hayward Fault. My house's foundation is byzantine (the kind of stone and mortar stuff they were doing ~2000 years ago!). But mostly it's to have stuff on hand... it keeps indefinitely is my experience. I sometimes make pasta and Italian sauce or pizza, and I always have plenty of that on hand in canning jars, plus other tomato concoctions which when heated up go nicely on cold winter mornings. I never buy jam, always make my own. It's better than the stuff they sell. I make batches, several to many jars at once, label them, store on shelves for whenever. Keeps indefinitely, is my experience. I never process my jams, they seem impervious to fungi or bacteria as stored when canned boiling hot.

 

[skyking]

I took inventory just now. 28 quarts of peaches, 9 quarts of tomatoes. I think I'll get two 20 lb lugs of each tomorrow and can on Sunday.

 

[Raizinman]

From Wiki

In home canning, food is packed into the jar, leaving some empty "head space" between the level of food and the top of the jar, then the lid is placed on top of the jar with the integral rubber seal resting on the rim. The band is screwed loosely over the lid, allowing air and steam to escape. The jar is heat sterilized in boiling water or steam. The jar is then allowed to cool to room temperature. The cooling of the contents creates a vacuum in the head space, pulling the lid into tight contact with the jar rim and creating a hermetic seal. Once cooled, the band is removed to prevent residual water between the jar threads and the lid from rusting the band. If the jar seal is properly formed, internal vacuum will keep the lid tightly on the jar. Most metal lids are slightly domed to serve as a seal status indicator: the vacuum in a properly sealed mason jar pulls the lid down such that the dome is concave, but an improper or failed seal or microbial growth will cause the dome to pop upward.

 

[dphantom]

I've read that the jars are supposed to be warm when filling.

That said, for me, I'm always adding boiling hot food (or at least boiling liquid in the case of syrup for some fruits) into the sanitized jars that are sitting on kitchen towels. Then putting the lid and ring on the jar, and submerging into already boiling water. Never had a problem, regardless of the starting temperature of the jar.

I usually sanitize the jars in the dishwasher - sanitize cycle, plus my tap water is 160 degrees. But, by the time I get to the 3rd or 4th batch, the jars are approaching room temperature. Sometimes, I sanitize the jars by boiling them for a few minutes. But, I sanitize all of the jars prior to processing any of them - the water in the water bath has to be deeper, because the water is going to fill the volume of the jar while sanitizing. Whereas when canning, the jars are going to displace a lot of water, raising the water level. Usually, if the jars are cooler, I'll turn them on their side and submerge them for a few seconds each to warm the jars. Not because I'm worrying about cracking, but so that after filling them, the cool jars aren't cooling the contents, leading to insufficient processing. Note: do NOT submerge jars by rapidly plunging them straight down into the water. As the water rapidly fills, it'll lead to a large splash from the center of the jar as the water rushing in from one side meets the water rushing in from the other side. Boiling water in the face isn't pleasant. If you forget this, you'll learn the hard way.

I do the exact same thing. Run a load thru the dishwasher to clean and sterilize. I process a couple hundred pints/half pints of jams each year, then peaches, various fruit pie fillings and vegetables from my garden. anything left over I make soup since I buy 1/2 a steer every year and always have some stew meat left over.

 

[jaha2000]

They will break for sure if you poor very hot stuff into them. I did that once, made a huge mess.
You either need to cool your stuff or temper the jars before filling.