Storing home canned food: metal rings off or on?

Home canning requires jars, lids, and rings (metal screw bands).  You place the food in the jar, position the metal lid on with the gasket side down, screw on the ring, and then process your jars.  After you remove the jars from the canner, some of the lids will already have formed a vacuum seal and others will make a popping sound as the vacuum forms a few minutes later as they cool down.  You then leave them alone for 12-24 hours, at which point they are ready to store.

So the burning question is: do you store the jars with the rings off or on or does it even matter?  My mother stored them both ways, as I often have, too.  I always thought this was because most people end up with more jars and lids than rings (jars initially come with lids and rings if you buy them new; after that you just buy replacement lids, unless you buy the jars used, in which case they will usually come with no lids or rings).

However, I’ve read on several sites that you should always store home canned goods with the rings off.  For example, Jennifer at Self-Reliant School advises:

Remove the rings. If the rings stay on and the lid fails (becomes unsealed) while the ring is on, the lid may reseal itself. However, bacteria has already invaded the jar and the food should not be eaten; with the ring left on there is no way you will know about the resealing. If the rings are off the lid has no pressure to reseal itself so if the lid seal fails then you’ll know and you can throw that jar out.

I thought about that for awhile, and I wondered if a lid could really re-form a vacuum seal just from the pressure of a ring.  I looked on the websites of the major manufacturers, but I couldn’t find any specific recommendations about this.

The National Center for Home Food Preservation says to store jars with the rings off:

If lids are tightly vacuum sealed on cooled jars, remove screw bands, wash the lid and jar to remove food residue; then rinse and dry jars. Label and date the jars and store them in a clean, cool, dark, dry place. For best quality, store between 50 and 70 °F. Can no more food than you will use within a year.

Do not taste food from a jar with an unsealed lid or food that shows signs of spoilage. You can more easily detect some types of spoilage in jars stored without screw bands.

So according to the government experts, you should store them with the rings off, but only because it is easier to detect a failed seal, not because a failed lid can reseal itself.  But I still wasn’t sure about that, so I decided to contact the Ball-Kerr company directly to see what they had to say.  Here is their reply to me:

Hi Sunshine,

Thank you for contacting us- hopefully we can help set the record straight regarding our suggested methods of storing your jars.

Although many of our consumers do choose to store their jars with the bands on, we don’t recommend doing so for two reasons. The first relates to the mechanism of the two-piece lid. The two-piece lid, initially marketed by the Kerr brand in 1915, is recommended for use due to the ease of determining seal quality. When spoilage occurs, gas builds up in the jar- the resulting pressure will cause the lid to come unsealed or pop.

Since the lid seals via an integrated gasket on the rim of the jar and the band grips the jar from a position below the rim, leaving the band on can indeed hold the lid to the jar when it shouldn’t be and make it appear sealed although spoilage has occurred. Earlier one-piece lids sealed on the bead or the shoulder of the jar –below the threads and rim- and thus couldn’t indicate a comprimised seal.

The second reason we don’t recommend storing your jars with the bands on is that it can, in some cases, impact the lifespan of your bands. Moisture that may be caught between the band and jar can cause the bands to corrode prematurely.

We hope this information helps! Please let us know if you need clarification.

Sincerely,

The Consumer Affairs Team

So there you have it: store your jars with the rings off so that if the lid seal fails, you’ll know it right away.  But if you store them with the rings on, when you take the ring off, just check that the lid is still vacuum-sealed onto the jar; if it is, then the seal has not failed because it cannot reform once it fails (but still check the contents of any jar with a visual inspection and a sniff whenever you open a new one).

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My now-ringless jars in the basement pantry

Canning mock lemon pie filling made with zucchini.

If you think you’re tired of hearing about my zucchini, just imagine how tired I am of dealing with it. 🙂  But I press on!  Waste not, want not and all that.

I really did grow other things besides zucchini, and soon I will tell you about how I’m preserving those.  But for now…

I found this recipe for Zucchini “lemon” pie filling at the site for Self-Reliance Magazine: Basic Skills for Living Well.  Since I’m trying to use and preserve as much of my over-abundance of garden zucchini as possible, I decided to give it a try.

Ingredients:

12-15 lbs. giant zucchinis, peeled and grated
58 oz. bottled lemon juice
lemon peel, grated, from 2 lemons
6 cups sugar

Directions: Mix all ingredients. Bring to a boil and simmer for 20 minutes. Fill sterilized jars with mixture, topping with remaining juice to leave ½ inch headspace. Process in boiling water bath, for 25 minutes.
To use filling for lemon meringue pie: Mix ½ cup sugar with 2 Tbsp. of cornstarch. Stir into “lemon” filling. Heat, just till thickened. Pour into baked pie crust, top with meringue and bake (400 degrees, 8-10 minutes) till meringue is slightly browned.

A few tips from me: I used the shredder side of the grater to make finer bits of zucchini.  I also used a lemon zester for the lemon peel.

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After you cook it for twenty minutes, it looks a lot like lemon curd,  We don’t eat lemon meringue pie all that often, but I will easily use these up making lemon bars.  I have school-aged children, which means I often need to provide baked goods for some event or other in which they’re involved.  I had thirteen pounds of zucchini, which yielded six quarts of “lemon” pie filling.

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I also made some zucchini bread to freeze today, leaving one loaf out for us to eat.  I usually use my mother’s recipe, which is moist and not too sweet, but I didn’t have applesauce, which the recipe calls for.  Instead, I tried Mom’s Zucchini Bread from All Recipes, and my husband preferred it.  I thought it was a bit too sweet but had a very nice texture and cinnamon-y taste.  Zucchini bread freezes well.

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I really think I am going to cut down the zucchini vines after tomorrow, though, and toss them on the compost pile.  Enough is enough already! 🙂

Sunday afternoon I’m planning to make rose hip jam, and if it goes well, I’ll share the details with you.

Complete Guide to Home Canning: useful, thorough, and free!

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Occasionally the government does something rather useful.  The National Center for Home Food Preservation is one of those useful things resulting from a partnership between the county extension at the University of Georgia and the United States Department of Agriculture.  If you go on their website, you can find the USDA’s Complete Guide to Home Canning, a free 196-page document broken into downloadable “guides”.  Here are the topics covered:

Guide 01: Principles of Home Canning
Guide 02: Selecting, Preparing, and Canning Fruit and Fruit Products
Guide 03: Selecting, Preparing, and Canning Tomatoes and Tomato Products
Guide 04: Selecting, Preparing, and Canning Vegetables and Vegetable Products
Guide 05: Preparing and Canning Poultry, Red Meats, and Seafood
Guide 06: Preparing and Canning Fermented Food and Pickled Vegetables
Guide 07: Preparing and Canning Jams and Jellies

If you are new to canning, read Guide 1.  It’s only about 35 easy-to-read pages long but it covers all the basics in a simple fashion.  I used a recipe for pickles from one of the guides and it was very easy to follow.   The recipes aren’t gourmet but they are straightforward, and they base their processing suggestions on research into the temperatures and times needed to safely kill all microorganisms for various foods.