Canning Jar Lids

The 2 piece canning jar lids that the USDA recommends consist of a screw band and a flat lid.

The flat lid has a sealing compound on the inside rim. I've also heard them called 'flats' or 'seals'.

The screw band part is reusable but the flat lid is not. After use the sealing compound will become indented which might interfere with a new seal.

Take a flat lid that has not been used and one that has and compare them. Look at the inside of the lids where the sealing compound is. You'll notice that after it has been used it will show an indentation where it sealed to your jar. This indentation flattens the sealing compound and it may not seal the second time around.

These can be purchased as a set of both parts or you can just purchase the flat lids.

How they work

Canning jar lids work by the vacuum seal formed by processing. The sealing compound on the lid sits against the jar and forms the all important seal.

The screw band fits over the lid and screws down to hold the flat lid in place. When placing your screw band you need to screw it down firmly but you do not need to be too forceful. Finger tight is fine.

As the food in the jar is being processed oxygen will be pushed out of the jar. As the food cools the lid will be sucked down and the rubber seal will form a tight seal protecting the food from any further contamination.

canning lids

Can you buy used?

Use caution if you are buying lids second hand. The flats are not reusable.

bac canning seals Even if they are "new in the box" you need to inspect them. Make sure they are not bent and check the rubber sealing compound. It needs to be rubbery and not dried out.

I purchased some seals at an auction. These were very old but they were in the box and had not been 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.

Where can I buy canning jar lids?

Canning jar lids can be found most anywhere canning supplies are sold. Walmarts may have them. I say may because for whatever reason the WM in my area does not bother to stock much canning supplies. They run out early. Don't know if they are all the same.

Ace Hardware Stores are your best bet. 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.

For online buying bulk the best price I have found is at Lehmans.

Click here to go to their canning section. Do a search for bulk canning lids. They have a great deal on these. These are generic brand and come in brown paper sleeves.

I split my order with a friend and ordered both wide and narrow mouth lids. I also purchased a canning rack for my canner. I was pleased with my purchases.

Lehmans sent my order in a timely manner. When placing my order on line I had a question and called the 800 number provided. The answer I got was friendly and helpful. I like friendly and helpful!