# Why boil/sterilize jars?



## Itsroger (Aug 28, 2015)

If the pressure canner gets hot enough to kill all living organisms, why boil the jars to sterilize them before filling them? I figure most of them get contaminated anyway, not trying to be a smart "A" , just wondering if there is a legitimate reason, besides, "we've always done it" .


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## Raeven (Oct 11, 2011)

I don't. I make sure they're clean, and I do preheat them either in the dishwasher or boiling water, but that's only to bring the jar temperature up enough so it won't stress the glass when I put hot contents into the jar before the canning processing period takes place. If you're sterilizing everything in and out of the jar during the pressure canning process, then sterilizing the jars before you add the contents is redundant, in my opinion.

In short, I think the same way as you do and haven't yet heard any reason why I shouldn't.


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## arrocks (Oct 26, 2011)

According to the guidelines you do not have to boil sterilize jars when used for anything that will be processed for longer than 10 minutes - either BWB or PC. You DO have to make sure they are good and warm if adding hot foods to them to avoid thermal shock breakage.
http://nchfp.uga.edu/publications/nchfp/factsheets/sterilizing.html


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## Itsroger (Aug 28, 2015)

Thanks, makes sense that a cold jar can break if filled with boiling liquid.


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## Murby (May 24, 2016)

If you are pressure canning, there is no need to "hot pack" your jars.. Just good warm or even hot water is fine but it doesn't need to be boiling. If you can hold your finger in the water, it won't crack a jar that is at room temperature. If it does, it was going to break anyhow.

No need to sterilize anything as a pressure canner at 240 deg pretty much does that anyhow.


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## arrocks (Oct 26, 2011)

Murby said:


> If you are pressure canning, there is no need to "hot pack" your jars.. Just good warm or even hot water is fine but it doesn't need to be boiling. If you can hold your finger in the water, it won't crack a jar that is at room temperature. If it does, it was going to break anyhow.
> 
> No need to sterilize anything as a pressure canner at 240 deg pretty much does that anyhow.


Well you can choose to ignore them of course but the instructions for pressure canning many things do call for "hot packing" the jars. But hot packing isn't the same thing as sterilizing.


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## Evons hubby (Oct 3, 2005)

I think a lot of people got in the habit of sterizing the jars while doing cold or hot packing, and simply carry it over into their pressure canning. Better safe than sorry and like that. There is no reason for it when pressure canning due to the greater heat involved. I don't monkey with washing perfectly clean jars either, I wash them as I empty them, place them upside down on a clean shelf ready for next time. They may have a bit of dust settle on their bottoms but that's on the outside, no harm no foul. A quick rinse in hot water (mostly to warm up the jar) and they are ready to be filled with whatever and pressure canned again.


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## termite76 (Apr 3, 2015)

I used to run my thru the pots and pans cycle on the dish washer instead. Now I just wash in hot soapy water, rinse. I do heat them up in the water bath canner to heat them up as I hot pack, for the glass stress reasons others stated.


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## GBov (May 4, 2008)

My book says to put food into HOT jars but, as I am canning raw, very cold fish, that seems a recipe for disaster to me.

So I have been heating the jars in the oven and letting them cool.

Would LOVE to skip that step, it already takes ages just to get the fish ready.


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## arrocks (Oct 26, 2011)

The guidelines for canning raw fish do not call for hot jars but you mind find that the processing time in the current guidelines is longer now than what your book may say.

http://nchfp.uga.edu/how/can_05/fish.html


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## GBov (May 4, 2008)

arrocks said:


> The guidelines for canning raw fish do not call for hot jars but you mind find that the processing time in the current guidelines is longer now than what your book may say.
> 
> http://nchfp.uga.edu/how/can_05/fish.html


 My book says HOT jars, even for raw packing fish. Its the booklet that came with my American canner.

100 min for fish and the bones are so soft and the fish tastes sooooo nice, I love it!

But the hot jar thing does confuse me, have to admit.


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## arrocks (Oct 26, 2011)

I understand what you are saying. However the current tested and approved guidelines do NOT call for hot jars.

That is one example of why using the canner booklet for canning instructions is not recommended. Not only are they not kept current, seldom revised as the guidelines change, and often contain errors. There are far better sources for canning information than canner manuals. They are fine for cooking instructions but not for canning.

The link posted above to NCHFP is considered THE definitive source for safe home canning instructions. It is the source that all other canning resources are based on.


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## bobp (Mar 4, 2014)

From a point of view of food safety, I'd rather sterilize them, just in case. 

Commercial Packers start with clean containers and the sterilize them, before packing and pastuization. Even canned pet food gets the treatment. 

I suppose it's as much for peace of mind if nothing else. 

We don't boil our jars though, we put them in the oven on the racks at 210Â°. When we're ready to fill just get out what you need.


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## GBov (May 4, 2008)

arrocks said:


> I understand what you are saying. However the current tested and approved guidelines do NOT call for hot jars.
> 
> That is one example of why using the canner booklet for canning instructions is not recommended. Not only are they not kept current, seldom revised as the guidelines change, and often contain errors. There are far better sources for canning information than canner manuals. They are fine for cooking instructions but not for canning.
> 
> The link posted above to NCHFP is considered THE definitive source for safe home canning instructions. It is the source that all other canning resources are based on.


 Ah, and here I was thinking that the booklet would HAVE to be better than the rest as it came with the equipment! 

Shall print out the link, it is soooo close to the booklet information but will rather have the latest, best information with no errors.


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## morninglory (Aug 7, 2003)

If I am using jars new to me, I boil them 20 minutes just like the old days of boiling baby bottles. if they are jars from my own " used many times" collection then I only concern myself that they are hot so that adding hot contents doesn't cause breakage.


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## TerriLynn (Oct 10, 2009)

I think in part that sterilizing jars falls back to a time when the "open kettle" method of canning was used. The open kettle method was to bring your tomatoes, or salsa or whatever you were canning to a boil in a kettle. After keeping your contents boiling for at least 10 min, you filled your sterilized jars and put the lids on they would seal. No further processing was done. I remember my grandma and my aunts using this method when I was a kid.


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## bobp (Mar 4, 2014)

The open kettle, or water bath method is still used with foods high in acids such as tomatoes, jams, preserves ect with sugar as a preservative...


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## arrocks (Oct 26, 2011)

Except that "open kettle canning" as normally defined didn't include any processing - you just slap the lid on and hope for a seal. They also used to call it the "inversion method" where the jars were just turned upside down after the lid was put in place. That lack of follow-up BWB processing is why the method has since been prohibited.



> *Why is open kettle canning not recommended?*
> In open kettle canning, food is cooked in an ordinary kettle, then packed into hot jars and sealed without processing. The temperatures obtained in open kettle canning are not high enough to destroy all spoilage and food poisoning organisms that may be in the food. Also, microorganisms can enter the food when it is transferred from the kettle to jar and cause spoilage.


 NCHFP FAQs


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## bobp (Mar 4, 2014)

OK what I was thinking as open kettle, would be the water bath method. Boiling for a prescribed amount of time after jarring up. Which is what I was describing for the jams jelly's high acids such as tomatoes ECT.


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## HoofPick (Jan 16, 2012)

Last year or the year before they changed the sterilization requirements. If the food processing time is more than 10 minutes then sterilizing the jars before hand is not required.


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## seehorse (Jul 20, 2008)

I have been successfully, and happily using a steam canner vs a water bath canner for about 30 years. Before I fill the jars, while I am prepping, I turn the jars over on the steam holes and let them get VERY HOT prior to the fill; This has always been a very effective method for me. I do the same thing when pressure canning just because when I am canning I am usually doing both (steam and pressure canning), it's a true adventure of love, it's like meditation for me. Good Luck


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## kenworth (Feb 12, 2011)

If my food is hot, they go in hot jars that I keep in the canner with water so they are about the same temperature. Cold pack go in slightly warm jars and the water temperature the same. This way all temperatures are relatively the same. Ingredients, jars, water. Just what I do


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