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Canning jar sterilization

post #1 of 24
Thread Starter 

I've always wanted to can things but never did it the right way.  Now is the time to get things right.  But a couple of questions:

 

1.  When sterilizing lids, is it also necessary to sterilize the rings?  I know they must be in place before water-bath processing but do they need to be sterile since they never touch the food?

 

2.  I'll be boiling jars this time, but what about other sterilization methods such as iodine sterilization used for beer bottles?  Is this a reasonable alternative to boiling?

post #2 of 24
I'm not an avid canner, but I've done it a time or two, and for me, I just sterilize everything in a water bath, just to be safe. I mean, you're going to preserve the product in the water bath anyways, right?
post #3 of 24
Thread Starter 

Right!  That is what I'm doing at this moment.  I was wondering and then remembered (after reading a USDA brochure on canning) that hot jars are better to pack hot contents into.  Duh... what I've done in the past is hot pack acidic items but not water bath process since the lids sealed OK.  Then I was refrigerating but now I want to be sure that they will be 'shelf stable".  Thanks very much.

 

Also I've been noting that the recommendations for processing have changed a lot - from 10 min at sea level to 5 minutes.  It is confusing when perusing a bunch of guides from different eras!

post #4 of 24
In addition, what I've read in various sources the head space as well as processing time varries depending upon what it is that you are canning.
post #5 of 24

You can sterilize rings if you want but not needed. DO NOT boil the lids, they should be placed into water that is barely at a simmer for the time suggested in the recipe or on the lid box. This is to soften the glue that seals the jar.

post #6 of 24
Thread Starter 

Thanks for that good advice, Mary.  Before getting too far into my adventure I read the USDA booklets on canning and the material provided at the Ball web site.   Interestingly, Ball does not even recommend simmering lids anymore.  So I wiped them off and put them onto the jars after filling and processed in water bath.  It all worked great.  Now I have 4 pints of zucchini relish and I'm ready to make something else soon with my new-learned skills.

post #7 of 24

Isn't that fun?

That's what makes cooking exciting

post #8 of 24

As to your query about alternatives to boiling the jars, I don't believe you have many options without resorting to chemical additives for preserving the product.

Generally speaking it's the acidity of the food being processed that's the key.

 

Two schools of thought here.

 

Many home cooks simply simmer the jars, and lids, have the product hot, fill the jars, wipe clean, place the lid and ring, tighten and Viola.

 

While this may work, it is not a guarantee that the product will be as safe to eat.

 

Alternately the product jars should be processed in a hot water bath for the allotted time to kill any potential bacteria.

post #9 of 24

I have a particular way of sterilizing my jars for making jams. Might not work for anyone, might not work for any kind of food canning but I never had a problem with canning jams. However, working absolutely clean is a must. I always recycle my own jars; many times I need to buy new lids.

 

For my jam, I only have a glass jar and a lid to care for. The lids are clad on the inside with a white rubbery layer like most modern lids.

I always wash my jars and lids first in very hot water with a good plain and simple washing liquid. Then rinse carefully, put them upside down to drain for a while. Then I turn them back up and... they go in my oven, set at a temperature of 110°C, a good tad above boiling temperature. The washed lids cannot go in the oven or you will never be able to open your jars once filled! Keep them after the cleaning in hot warm water until use.

 

The jars stay in the oven until needed, moments before filling them. How long? The time I need to boil the jam, mostly 15-20 minutes in total. When ready, I take a few jars out of the oven at a time, using kitchen tongs. Fill, put a lid on, grab a towel to turn the jars upside down and leave to cool; done! You'll be surprised how much force you're going to need to open a jar! Last week, I opened a new jar that was dated... 2 years ago; nothing unusual for me!

 

Heating the jars to such a high temperature allows me to pour extremely piping hot jam in them, coming straight from the heat! I never had a jar that burst.

When filling, make sure not to spill one single drop on the edges, use a funnel with a wide opening (available in cooking shops).

post #10 of 24

"Empty jars used for vegetables, meats, and fruits to be processed in a pressure canner need 
not be presterilized. It is also unnecessary to presterilize jars for fruits, tomatoes, and pickled 
or fermented foods that will be processed 10 minutes or longer in a boiling-water canner."

 

http://nchfp.uga.edu/publications/usda/GUIDE%201%20Home%20Can.pdf

 

I always process my stuff for 10 minutes so I don't have the extra step of sterilizing. If you have to boil a bunch of jars anyway you might as well put the food in first, right?

 

When I had a dishwasher I kept the jars hot in there or just rinsed in hot tap water before filling. That was plenty hot enough to keep them from breaking when filling. 

post #11 of 24
Thread Starter 
Quote:
Originally Posted by Chefross View Post
 

...

 

Two schools of thought here.

 

Many home cooks simply simmer the jars, and lids, have the product hot, fill the jars, wipe clean, place the lid and ring, tighten and Viola.

 

While this may work, it is not a guarantee that the product will be as safe to eat.

 

Alternately the product jars should be processed in a hot water bath for the allotted time to kill any potential bacteria.

So this I exactly the transition I'm making.  I generally would hot-pack into clean (not necessarily sterile, though) jars and cap with sealing lids.  Then cool and the lids would "pop".  But then I'd refrigerate or freeze for storage since I was concerned about food safety.

 

Now I'm more interested in shelf storage.

 

I asked my mother-in-law about her canning history and she took the first approach, shelf stored, and was happy to report that nobody ever got sick eating her canned fruits.

 

Maybe the water bath (or pressure) processing is excessive but the more I research the more I think I believe that for shelf storage over a longer period of time it may be worthwhile.

post #12 of 24
Thread Starter 
Quote:
Originally Posted by ChrisBelgium View Post
 

I have a particular way of sterilizing my jars for making jams. ...

Thanks; a lot of good information to consider!

post #13 of 24
Thread Starter 
Quote:
Originally Posted by mtullius View Post
 

"Empty jars used for vegetables, meats, and fruits to be processed in a pressure canner need 
not be presterilized. It is also unnecessary to presterilize jars for fruits, tomatoes, and pickled 
or fermented foods that will be processed 10 minutes or longer in a boiling-water canner."

 

http://nchfp.uga.edu/publications/usda/GUIDE%201%20Home%20Can.pdf

 

I always process my stuff for 10 minutes so I don't have the extra step of sterilizing. If you have to boil a bunch of jars anyway you might as well put the food in first, right?

 

When I had a dishwasher I kept the jars hot in there or just rinsed in hot tap water before filling. That was plenty hot enough to keep them from breaking when filling. 

Thanks very much. I found that entire series of booklets yesterday.  Great reading, but it did dissuade me a  bit from thinking about canning anything requiring pressure sterilization (I don't have a pressure cooker and wouldn't know where to store a large one anyway).

 

I was thinking the same about pre-sterilizing the jars.  Seems like a potentially extra step if everything gets sterilized during the waterbath processing.  The dishwasher seems like a very reasonable way to get "near sterile".

post #14 of 24
I've also heard you can put the jars in the oven to steralize... never tried it, so can't vouch for it. .
post #15 of 24

Oven sterilizing is an untested and unproven method. Want to bet your health on it? Might not get sick doing it 4 times, 5thmight bite you with botulism or some other nasty. I follow the instructions given for each recipe and do not gamble with my health.

post #16 of 24
Quote:
Originally Posted by MaryB View Post
 

Oven sterilizing is an untested and unproven method. Want to bet your health on it? Might not get sick doing it 4 times, 5thmight bite you with botulism or some other nasty. I follow the instructions given for each recipe and do not gamble with my health.


I don't gamble with my health at all. I did this oven sterilization hunderds of times and I'm still around and I will keep on doing it.

post #17 of 24
I would not recommend attempting sterilization in an oven but would do it in combi oven. These units can produce high temp steam. You can sterilize the jars and then process the sealed, filled jars without the hassle of a water bath.
Edited by saleschef - 6/29/14 at 2:58pm
post #18 of 24

I will stick to proven methods until the USDA says it is safe to use an oven. The only jars that really need it are those with short water bath times or for making my refrigerator pickles where boiling brine is poured over packed jars, lids and bands put on then let cool(They usually seal while cooing). Once cool they go into the fridge for storage up to a year.

post #19 of 24

Wow, what an interesting topic to me! 

 

First, I think you're pretty darned smart, Brian, to take this to the next level. The type of canning you used to do is called "open kettle" in USDA lingo. It's not recommended for shelf stability (but great for refrigerating) because open kettle does not create a true vacuum. If the safety seal punches down, it does so only because the ingredients have cooled and contracted, but the oxygen in the head space is still there, and will remain there until a high heat process (water bath or pressure) is applied and the molecules exit the headspace through the 2-part lid. 

 

As long as you stick to high-acid foods, water bathing will be enough. BTW, I'm privy to many commercial applications of food safety. You may wash your jars and then store them on trays in the oven, on low heat, until you need them. The risk is this: if the oven heat is cranked too high, there is the chance that the glass jars, when introduced to the cooler kitchen air, will crack, or worse, explode in the cook's face. All commercial canneries keep their jars hot (but not immersed in water) before filling them. 

 

I teach canning using USDA consumer methods, with a few commercial methods thrown in. Many students are worried that they will encounter relatives (who don't use USDA methods) who'll give them a hard time for processing their jars because "no one ever got hurt."  I'm going to tell you the story I tell them.

My Quote:

"Let's say every day I drive to Kroger. Might be for a lot of groceries, but it might be for a cup of coffee. Kroger is my second home, only 2 miles away! I relax on the drive, because it's a quick and pretty, and I've never had an accident.

 

So one day I tell my kids, don't buckle up. Heck, we're only driving to Kroger. I can drive there in my sleep, and nothing has EVER happened to me -- or us!

 

So my kids jump into the back seat with no seat belts. 

 

Halfway to Kroger, a car approaches mine. The driver is texting and doesn't see me. He suddenly swerves into my lane and crashing into my car head on, flipping it. My unbuckled kids go flying out the window and are killed. (OK, I HATE this part of the story...)

 

I didn't expect that driver. I couldn't control him. If I'd only taken a few seconds to buckle in my children, we'd all be safe."

 

Of course, the driver is botulism. It is unpredictable and undetectable. At least you can smell and see yeast or mold (the two other bad boys in canning), but botulism cannot be seen or smelled. It is a natural force of nature that may be present in low-acid foods, and can only be killed in ultra-high temperatures brought by pressure canning.

 

Yeasts and molds are killed by a quick water bath -- easy. After all, good fruit is hard to come by, and who wants to take the time to cook a fabulous strawberry preserve in June, only to find gross hairy mold enjoying it immensely in February? 

 

Sounds like you enjoy high-acid canning. So simmered lids, room temperature bands, hot jars, hot ingredients, and water-bathing for the time allotted by a qualified canning recipe will keep you and your family safe, while allowing you to have delicious, shelf-stable items on your shelves.  Sorry, this is more information than you asked for, but this is a topic I savor...  Let us know what you create!

post #20 of 24

well said @jamlady

post #21 of 24
Quote:
Originally Posted by jamlady View Post
 

.... You may wash your jars and then store them on trays in the oven, on low heat, until you need them. The risk is this: if the oven heat is cranked too high, there is the chance that the glass jars, when introduced to the cooler kitchen air, will crack, or worse, explode in the cook's face. All commercial canneries keep their jars hot (but not immersed in water) before filling them. ..

 

 

 

I put my jars in a 110°C/230°F oven, which is not particularly low, it's well above the boiling temperature of water. I'm pretty sure bacteria and molds are dealt with. And as explained earlier, this allows me to fill the jars with piping hot jam which is at that moment on an even higher temperature than the hot jars! You cannot do this with jars at low temperature or they will burst. I never had trouble with jars heated to 110C/230F. On the contrary, nothing but advantages as far as I can tell from my extended experience with jams. The vacuum that is created is incredibly strong, but that could also be the result of the quality of the used jars and more specific, the lids! I still have jams that are jarred more than 2 years ago that still are perfect and will be consumed.

All of the jams that I posted in this thread and many others are jarred that way; http://www.cheftalk.com/t/77349/what-kind-of-jams-are-you-making-its-jam-time

post #22 of 24
So Chris, are you using lids that have been used on previous jars?
I was told that I should never reuse lids, only rings... But then you're use one piece lids, is that correct?
post #23 of 24
Quote:
Originally Posted by kaneohegirlinaz View Post

So Chris, are you using lids that have been used on previous jars?
I was told that I should never reuse lids, only rings... But then you're use one piece lids, is that correct?


That's precisely what I wrote in post #9.

post #24 of 24

Hi Chris,

 

I like your temperature. That's what I call "low", as opposed to the general 350 that a lot of people automatically turn their oven to. Some digital ovens won't even go as low as 110, so you've got great flexibility with your stove. 

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