Guide to Canning Jar Lids

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Canning jar lids might seem a simple topic, but there are things to consider. What is suggested? What alternatives? How do you use canning lids? Where do you get them? Find out more in this canning jar lid guide.

How canning lids work: As the food in the jar is being processed, oxygen will be pushed out of the jar. The sealing compound in the lid warms and softens fitting itself tightly against the jar. As the food cools, the contents shrink and the lid will be sucked down and form a tight seal protecting the food from any further contamination.

Regular and wide mouth Ball flats and rings.

I thought this would be a short post… but when I started there were so many things to share!  Be sure and check the Table of Contents. 

How Canning Lids Work

When you put your filled jars in a canner to process, the screw band fits over the flat lid and screws down to hold the flat lid in place during processing.  Bacteria or spoilage causing organisms are killed by the correct level of heat in the canner.

NOTE: A pressure canner gets to a much higher heat than a water bath or steam canner. This is why we use pressure canning for vegetables and low acid foods. Learn how to choose the right processing method here.

There is a vacuum seal formed during the cool down period. The sealing compound on the inner rim of canning lids sits against the jar, as the food cools it shrinks and sucks down on the lid, the gasket forms the all-important seal.

Tightening a ring on a jar of chicken soup.
When placing your screw band, you do not need to be too forceful. Finger tight is fine. 
Learn how to get your canning jar lids finger tight.

Types of Jar Lids.  

There are 2 types of canning jar lids commonly used in the US.  

  • 2 piece set consisting of a flat metal lid and a screw band. 
  • Re-useable canning lids which are plastic with a gasket.  These actually have 3 pieces but are very similar to the metal lids.

There are also reusable lids and glass Weck brand jars and lids. 

Let’s go over all these types of jar lids. 

Sizes

All of these lids come in 2 sizes to match the opening of the 2 commoncanning jar mouth sizes.

  • Standard jar mouth opening is about 2-3/8 inches.
  • Wide mouth jars have openings of about 3 inches.

The screw bands that hold the lids on the jars also come in the same 2 sizes: Standard and wide mouth. 

Traditional Metal Canning Lids 

The National Center for Home Food Preservation (NCFHFP) recommends using the standard 2-piece lid system. 

  • Have been extensively studied
  • Are easy to use
  • Easy to determine if they are sealed
  • Extremely reliable

The system consists of a screw band and a flat metal lid, sometimes referred to as ‘flats’ or ‘seals’.   The ‘flat’ usually comes with a food safe coating on the bottom portion that contacts your food.   Around the rim is a rubber like compound that acts as a gasket. This is the part that forms that ever important seal.  

What are the gasket in the lids made of?

The gasket in lids are made up of either rubber or silicone.  Different brands will use different products.    The coating on the lid is also something to consider.  Many companies have a BPA free coating as well.  Your best bet is to check with the company for their exact specifications.

What Brands are Recommended?

The NCFHFP does not officially endorse any specific brand.  But…please note… there are different qualities available.  Watch for reviews and watch for cheap copycat websites.  I’m not saying anything not Ball is bad.  On the contrary I listed some good companies to buy from just below.  But there have been many sites popping up with poor quality.  Some even claiming to be Ball… but when you get your lids, they are not.   

Why are recommended mason jar lids two pieces?

You’ll see one piece canning lids being sold as well as the two piece.  The reason the two piece is recommended is how the lid vents, and how you can see if it has sealed properly. 

This is a good explanation. From the North Carolina State Extension. 

“When used as intended, with recommended headspaces, the standard two-piece metal lid system first; allows for very good exhaustion of air from the headspace during the canning process (this is necessary for the formation of a strong vacuum), second; provides a visual indication that a vacuum has been pulled and maintained, and third; maintains an excellent seal throughout storage of the canned food.”  

Other Options 

The following options have not been officially endorsed by the NDFHFP.  There was a limited study done with both Tattler brand reusable canning lids, and Weck canning jars and lids.

“These findings continue to demonstrate the expected success with the traditional two-piece metal lid system while not discouraging the use of the plastic and glass lids.”

Basically the results resulted in a strong recommendation for the metal 2 piece style lids, but stop short of stating metal or glass lids are dangerous.  They simply need to be tested more. 

So… use these at your discretion.  :). 

Reusable Canning Lids

Reusable cunning’s are slightly different but very similar to the ‘2 piece’ system that I mention above.  These have a flat lid that is plastic, a separate reusable gasket and are used with the same screw bands.  I’ve gotmore on my personal experience with reusable canning lids here.

Weck Jars and Lids 

Weck jars are not very common in the US.  They are expensive but sooo beautiful.  I have not used them myself.  If I were to ever get some I’d consider using them for things like jams and jellies.   They would be perfect for gift giving. Check out more here… Weck Jars

Where Can I Buy Canning Jar Lids?

Lids can be purchased with both the bands and the flats. Or if you already have screw bands, reuse those and just purchase more flats.

I’m always a fan of buying local. Our local Ace Hardware carries canning supplies. If you use a lot of lids and want to buy them all at once, ask for a discount. I asked at our store and they gladly worked with me on the purchase of a case. Other big box stores also carry canning lids.

Online purchasing is convenient but please use caution to avoid scams. Be sure you are buying from a legitimate, established business. With the recent shortages of canning supplies, there are scammers out there. Check websites for informational about pages, location, and clear copy on the website, including a clear return policy. 

Buying Lids in Bulk

If you are placing orders online, often you will get them cheaper per box if you buy several boxes at a time. Bulk lids in sleeves are another great way to buy. 

I do this myself. Fillmore Container is a sponsor of SimplyCanning, and they carry canning lids in bulk sleeves. These are generic, but they are from a good supplier. I’ve had good luck with them.  (Remember not all off brands or generic lids are poor quality.  It is more about the reputation of the company you purchase from and the quality they provide.) 

Bulk sleeves of canning jar lids.

Buying Lids Secondhand

Can you buy second-hand lids if they are new and in the box unused? I am a fan of bargain shopping. However, use caution if you are buying lids secondhand. Even if the lids you purchase are “new in the box”, you need to inspect them. Make sure they are not bent and more importantly, check the rubber sealing compound. It needs to be rubbery, soft, and not dried out.

A Little Story…

I purchased some seals at an auction. Now, I LOVE auctions! My husband and I regularly scour through old boxes of “stuff.” We enjoy it. We get some great deals at times.

This time was not one of those. I found a box full of jars and some boxes of seals. The seals were very old, but they were in the original box and had not been opened or used. At first glance, they looked like new. I thought I’d found a great deal.

However, when I heated them before placing them on my jars, I noticed that the sealing compound was peeling. Definitely not usable. The sealing compound was totally dried out. Very flat. No rubbery feeling to them at all. They were just too old.

Jars Sold with Lids in Place Are a Bummer

Sometimes jars are sold with lids on them in the box, which can cause indentations….I hate it when they do that. So check those lids when you take them off new jars. You’ll have to decide if the lid is in good enough condition to use.

This, of course, leads to the next question…does it matter? My answer is “Yes, it does matter.” Remember that sealing compound? If it is damaged, it can make a failed seal more likely if you try to reuse the lid. I don’t like to waste my time and food for a higher chance of failure.

I’m sure the boxes probably get warm while in storage, either with you after you purchase, or with the store before it is stocked. The heat will just exacerbate the problem as the sealing compound gets soft when heated.

Your best bet is to remove the lids from the jars when you get them. As far as them still being useable, it will depend on how deeply the jar seals are marked. That is something I can’t really tell you. You’ll just have to decide if it is worth risking a failed seal. If the indentation is very light, they may be fine…they may not. If it is deep though, I don’t recommend trying it.

Do Canning Lids Expire? How Long Will They Last?

Canning lids do have a shelf life. I am talking about unused lids in the box. Not lids on jars. I’ve seen it recommended that you not buy more than what you will use in a year. But then, I’ve also seen that unused lids will be good for 5 years. Seems like they contradict, right?

This is the quote I found from the NCHFP:

“Gaskets in unused lids work well for at least 5 years from date of manufacture. The gasket compound in older unused lids may fail to seal on jars. Buy only the quantity of lids you will use in a year.”

My opinion: I used to think that the 5-year date is a good number to go by. However, I do know that lids have changed and the quality varies. It seems like the rubber compound is not the same as it used to be. I recommend you don’t buy too many. 

You might as well not push that date. One year’s supply is pretty good, but if you go over, certainly don’t throw your lids away. Even planning for 2 years would probably be okay.

More importantly, store your lids safely. No high heat! (Hot garages or sheds are not a good idea.)

How Can You Tell If a Canning Jar is Sealed? 

The best way to tell if your lid sealed properly is to allow the jar to cool naturally to room temperature. Overnight is what I always do. 

Then remove the screw band and lift the jar by the edge of the lid. The lid should be able to hold the weight of the jar and will not come off. 

You can also check that the lid is sucked down and has a vacuum. Press your finger on the middle of the lid; there should be no give. It should not pop up and down.  

Can You Reuse Metal Canning Lids?

The screw band part is reusable but the flat lid is not. The flat lid has a sealing compound on the inside rim which, after use, will become indented. You can see this indentation. This dent might interfere with a new sealon any future batches. It can cause it to not seal at all, or just create a weak seal that may come loose in storage.

Notice I say “may” and “might.” It is a risk that some people are willing to live with. For me, I’d rather know my lids will be secure.

Now having said that…you might have a zillion lids laying around or you feel like surely there is something you can do with these instead of tossing them in the landfill. It IS okay to recycle lids for purposes other than processing. I’ve got more on recycling canning lids here.

How to Tell If Your Lids are New or Used

It’s all in the seal.

I was asked how to tell if a lid has been used. You can tell by the sealing compound. If it is used, it will show an indentation from the rim of the jar. If not used…it will be smooth. I took a picture of two lids. One is used, one is new. Can you tell the difference? (Answer below the picture…)

A new canning flat with a used canning flat beside it.

It might be hard to tell, but the lid with the gold finish is the new lid. The lid with the white finish is the used lid. It is not the color (white or gold) that indicates which is new or used. Canning jar lids are made in both colors. It is the condition of the sealing compound that you need to look at. If you see those indents, the jar is likely used.

Are Canning Lids Supposed to Pop?

  • How long does it take for jar lids to pop when canning? 
  • And what happens if lids don’t pop?

You will generally get a popping sound within an hour or so of taking them out of the canner. But it is not always so, and that is okay. It does not indicate a problem. 

Is the jar sealed, even if you didn’t hear that ping? Find out more on this canning chat about popping lids.

An Unusual Situation. 

I received this question in my inbox.  I’ll share it here just in case you’ve been in a similar situation.  

Question : Is a Jar with Two Lids Stuck Together Safe?

I canned somedill pickles and discovered after the fact that two lids had stuck together on one of the jars. The top lid is sealed, but I wonder about the lid underneath it. I did not want to disturb it as I thought that could break the seal. What do you think? Perhaps I won’t know until I open the jar.

Answer: What I would do is test the seal just as if there were only one lid. Lift the jar off the counter by the edges of the lid. The seal should be able to support the weight of the jar. As long as it does, I would think your seal is probably fine. Don’t be afraid to jiggle it a little. If the lid comes off easily, then it wasn’t strong in the first place. You want to know that now, not later.

I Talk Canning Jar Lids Live

Jars of peaches labeled accordingly on the flat lids.

Related Pages

What About the Canning Jars? – What are the different sizes and shapes of canning jars? What brands are out there? Can I reuse jars from the store or vintage jars? Get all of your canning jar questions answered here!

What Happens If You Don’t Hear that Pop of the Canning Lid? – Is it sealed? What might have prevented that seal when it comes to your lids? Learn some common mistakes here.

Can You Recycle Other Glass Jars for Canning? – Specifically, can you reuse jars from other products like store-bought pickles for canning? SimplyCanning gets this question often. Here’s the scoop.

Canning Jar Lids

Resources:

  • https://blogs.extension.iastate.edu/answerline/2022/03/15/are-two-piece-lids-really-necessary/
  • https://getd.libs.uga.edu/pdfs/sivanandam_geetha_201412_ms.pdf?fbclid=IwAR3fwuyoYV0CxnMGp698NSjEtNK9BrYphAI0VTC0RRTEh1bkQdPlhLIv_Q8
  • https://foodsafety.ces.ncsu.edu/2020/10/two-is-better-than-one-especially-when-it-comes-to-canning-lids/

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Cindy
Cindy
1 year ago

I heated more lids than I ended up using. Will I be able to use those lids in the future?

sharon
sharon
1 year ago

Do you sterilize your lids? If so, how do you do it? Thanks

Karl
Karl
2 years ago

I’m having a tough time getting a definitive answer to a question regarding seal gaskets. Which material is better for heat/pressure canning…rubber or silicone?

Johnnie Searle
Johnnie Searle
2 years ago

My first batch of tomatoes(raw pack/water bath) have a couple of jars that didn’t seal. Can I use new lids and try to get them to seal? Reprocess?

Pat
Pat
2 years ago

Hi
Is it necessary to vacuum seal powdered chili verde enchilada mix? The ingredients are: peppers, garlic, onion and salt.

Rachel Abernathy
Admin
Rachel Abernathy
2 years ago
Reply to  Pat

It would be up to your preference. 🙂

-Rachel (Sharon’s assistant)

Pat
Pat
2 years ago

Thank you for your consideration and time!

Donna
Donna
2 years ago

How do you know if a lid is sealed if it doesn’t have a pop button?

Rachel Abernathy
Admin
Rachel Abernathy
2 years ago
Reply to  Donna

From the page: “The best way to tell if your lid sealed properly is to allow the jar to cool naturally to room temperature. Overnight is what I always do then remove the screw band and lift the jar by the edge of the lid. The lid should be able to hold the weight of the jar and will not come off. You can also check that the lid is sucked down and has a vacuum. Press your finger on the middle of the lid, there should be no give, it should not pop up and down.” If you’re using… Read more »

Marbella M Perea
Marbella M Perea
2 years ago

On the wide mouth lids that I use there is in the middle a round circle that is lifted a little bit. Does this mean the lid is new and will go down after the processing. Is this what pops?

Rachel Abernathy
Admin
Rachel Abernathy
2 years ago

Yes, exactly right! As Sharon says on this page, “You can also check that the lid is sucked down and has a vacuum. Press your finger on the middle of the lid, there should be no give, it should not pop up and down.”

-Rachel (Sharon’s assistant)

Vivian
Vivian
2 years ago

Where are thecanning lids made?

Rachel Abernathy
Admin
Rachel Abernathy
2 years ago
Reply to  Vivian

It would depend on the brand, Vivian. I think Ball lids are made in the USA, however.

Rachel (Sharon’s assistant)

Kate
Kate
2 years ago

Any idea what the “sealing compound” material is? Rubber? A polymer?

Cher
Cher
3 years ago

Do you know what the sealing compound around the lids is? What is it made of?
Many Thanks.

JENNIFER
JENNIFER
3 years ago

Are off brand lids safe to use? Due to the pandemic the few Ball brand lids I find on Amazon are over priced but off brand ones are reasonable. I’m new to canning and am loving the information you provide!