There are one-piece canning lids (aka “Twist-top lids”), such as you see on commercially-purchased bottled goods, that are sold for home canning use.
You put them on jars and process the jars. According to the manufacturers, if a dimple (sometimes called a “safety” button) in the middle gets sucked downwards afterwards, that is how you know they sealed. [1] McClellan, Marisa. Canning 101: How to Use One Piece Lids. Blog post. 9 October 2012. Accessed March 2015.
You will see these types of lids sold with many European and British preserving jars. Some people say that in the parts of the world they live in, they can only buy one-piece lids and have no other option.
But in North America, they are specifically recommended against for home canning.
The University of Minnesota says,
(Q:) Can I use one piece canning lids for home canning? (A:) No. One piece screw type canning lids are not designed or approved for home canning use. This type of lid is used in food processing as a hot-fill-hold process under very strict time and temperature controls. In home-canning a two-piece lid is needed to let the air escape during the boiling water or pressure canning process. A one-piece lid doesn’t allow the air to escape resulting in blowing out the bottom of the jar or the lid to buckle. [2]Driessen, Suzanne. Food Preservation FAQs. University of Minnesota Extension. 2014. Accessed June 2015 at https://www.extension.umn.edu/food/food-safety/preserving/general/food-preservation-faqs/.
In the interest of balance, and deeper understanding, it’s important also to take notice of this explicatory note in So Easy to Preserve (whose authors assist with the USDA Complete Guide):
Some of these jars have one-piece or other types of lid systems that may or may not offer the same type of air venting and sealing success as the two-piece metal lid system….. As long as the proper jar type, size and shape is used with properly researched canning procedures, the lid choice itself (e.g. two-piece metal, plastic or one-piece metal lids) does not affect the microbiological safety of the canning process. The issues become ease of use, success in sealing and maintenance of vacuum and food quality during storage.” [3]Andress, Elizabeth L. and Judy A. Harrison. So Easy to Preserve. University of Georgia Cooperative Extension. Bulletin 989. Sixth Edition. 2014. Page 24.
Popular one-piece lids include those made by Quattro Stagioni.
Many people re-use the one-piece lids and in fact they are often sold as re-usable.
Some one-piece lids are made with “buttons” embossed in the centre, which are meant to be visually “depressed” when there is a vacuum present. Healthy Canning has found though that just how “depressed” counts as “depressed” appears to be open to interpretation by various people, especially if a vacuum is weak.
Healthy Canning does note that in Australia and New Zealand, many people who otherwise try to follow modern canning recommendations from reputable sources do none-the-less often find themselves compelled for economic reasons to consider using one-piece lids, simply owing to the often prohibitive prices of two-piece lid systems in those countries.
In any event, the recommendation against is not based on a microbiological safety issue per se, but rather on operational issues:
- Do all one-piece lids provide sufficient venting during home canning processing to create a strong and lasting vacuum seal, and how strong does that vacuum rate in comparison to that created with two-piece lids?
- Do all one-piece lids provide a way for home canners to check on the integrity of the seal, without actually having to open the jar at a time when they don’t actually want to?
In any event, as we noted, the recommendation at the present time (2017) in North America is against using one-piece lids for the operational reasons listed above. The National Center for Home Food Preservation (which coordinates home canning research on behalf of the USDA) has simply not had the funding yet to study the issue enough to be able to recommend it positively at the present time. They aren’t allowed to “guess”, and when they make a recommendation, it has to be good for hundreds of millions of not-always careful users, not just one careful household, and the last thing they would want is a flood of complaints from people who had seals fail on the shelf and food spoil.
NOTE: Healthy Canning also notes that even commercially-purchased jars of food with one-piece lids sometimes are not actually sealed. We would advise consumers not to take a safe seal for granted on any jars, even store-bought ones, and to take a second to examine the jar lid first before opening.
History
One piece canning lids used to be made under the Kerr name a long time ago. In 1976, a firm called Klik-It Corp. in Chicago began selling one piece Mason caps called “Klik-It” lids, but they don’t seem to have survived in business. [4] Brookshire, Paula. New Lids Here to Stay? Milwaukee, Wisconsin: The Milwaukee Journal. Wednesday, 12 May 1976. Page 5.
References
| ↑1 | McClellan, Marisa. Canning 101: How to Use One Piece Lids. Blog post. 9 October 2012. Accessed March 2015. |
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| ↑2 | Driessen, Suzanne. Food Preservation FAQs. University of Minnesota Extension. 2014. Accessed June 2015 at https://www.extension.umn.edu/food/food-safety/preserving/general/food-preservation-faqs/. |
| ↑3 | Andress, Elizabeth L. and Judy A. Harrison. So Easy to Preserve. University of Georgia Cooperative Extension. Bulletin 989. Sixth Edition. 2014. Page 24. |
| ↑4 | Brookshire, Paula. New Lids Here to Stay? Milwaukee, Wisconsin: The Milwaukee Journal. Wednesday, 12 May 1976. Page 5. |
Stephanie
Of course American authorities are telling people that tried-and-true methods, such as the Quattro Stagioni 1-piece lids, are “not qualified for home use” – they can sell more 2-piece, 1-use lids that way! But I will tell you now that, here in Switzerland, and in Italy, Germany, Britain, and indeed every other European country that I have lived in or been in for any amount of time (I’ve lived in Switzerland for 30 years) use the 1-piece QS lids. I’ve used them (in hot-bath canning) repeatedly, without problems! I use the same lid for canning until it’s either dented or showing signs of rust. They seal without fail every time.
Jen
I’d like if I could to just add a bit of personal observation to the discussion of the Quattro Stagioni one piece lids. I am in no way recommending anyone ignore the USDA advice or view anything I write as advice, I just have a lot of personal experience with these particular lids that I thought in the interest of an open dialog on the topic someone may find of interest. It seems that the USDA has lumped all one piece lids together and stated they are not safe for a few specific reasons, however in my personal experience with these particular one piece lids, I found that the USDA’s statements are not consistent with what I have observed. Again I am not implying that my personal observations account to a scientific study, I just thought someone might find my observations that conflict with the USDA’s statements useful.
The USDA states that one piece lids do not allow air to evacuate during the home canning process, however this is not what I have observed over hundreds of uses with the Quattro Stagiono one piece lids. I have boiling water bath processed jars with Ball two piece lids right alongside jars with the one piece Quattro Stagioni lids and I have seen them both evacuate air in bubbles in what appears to me to be the exact same rate. When I peer into the canner while it’s heating up, for example, I can watch the air bubbles come out of both types of lids identically and can observe no difference in the air evacuation during processing between the one piece Quattro Stagioni and two piece Ball lids. Also, both lids have a very similar tacky sealant ring around the underside edge of them. On the Ball it’s orange and on the Quattro Stagioni it’s white. I’m not really sure how the QS one piece lids are able to work in what appears to be the same way as the two piece lids in terms of air evacuation during canning, but they do appear to allow air to evacuate just like the two piece lids as I can observe no difference when comparing them side by side over and over for years.
Additionally, the USDA says that there isn’t a safety mechanism on the one piece lids to see that they are sealed, however the Quattro Stagioni one piece lids have 2 safety checks. First of all the QS one piece lids have the same domed shape as the Ball lids where the center part of the lid is raised up and when it isn’t sealed can be flexed up and down when you press on it. Just like with the Ball lids, the QS lids very audibly “ping” after processing when the center of the lid pops down and becomes depressed visually and tactilely and becomes rigid and no longer flexes when pressed down. In practice the QS lids act and appear and feel just like the Ball lids in this respect. The first safety check with the QS lids, just like with Ball, is that you can just push down on the center of the lid to check if it’s still firm and concave to know that it’s still sealed. Again in this respect, to me they function in the same way as the two piece lids. Also, with the Quattro Stagioni lids, there is a second safety check, which is when you go to actually open the jar. If the lid is still depressed and sealed then when you open the jar you will hear a very loud “pop” sound…this is loud and unmistakable. What is nice about this feature is that one can choose to be extra cautious and decide that even if the lid passes the test of not flexing when pressed in the middle and being still in the popped down position like the Ball two piece lids, with the QS lids to be extra cautious one could also decide that if they do not also hear the distinct pop when opening the jar then they will not use the contents even if the lid was still popped down and rigid. Now personally I have never had a QS one piece lid ever become unsealed and they have always both remained concaved down in the center after they ping when removed from the canner, and they have all also loudly popped when opening the jar for the first time after sealing. But still, my rule personally has always been that I would only use the contents if they passed both of those safety checks and I’m glad to have the 2 ways to know the jar has remained sealed.
So again, I am not advocating the use of the one piece lids from this or any other brand, and I am not suggesting that any of my observations are scientific studies. I simply have noticed that the particular reasons the USDA has stated for not recommending any one piece lids don’t actually seem to mesh with what I have observed over and over again with the particular Quattro Stagioni one piece lids that I have used. I understand that it is likely because the role of the USDA is to be a place we can turn to for absolutely safe information and they haven’t likely done much research into various styles and brands of these lids and it makes sense for them to lump them all together etc. I simply thought I might add a bit of information to the discussion on this topic in case anyone is interested because I haven’t seen where anyone has ever commented specifically on the particular reasons the USDA has used to outlaw these lids, I have only seen general comments about them being well respected in their country of origin. Hopefully I have made it clear that my observations are not recommendations but simply information I felt someone else might find relevant in their research on the topic. I personally like to read all the information I can find on a topic like this when I am trying to learn more about something and I haven’t been able to find a lot of details on these particular lids on the internet so I thought I would share my personal experience.
Richard Convers
One piece lids work just fine for hot water bath canning. They will take longer to “pop”, up to an hour, but they seal fine. Been using them for years.
Jonathan
I have a query on the type of lids. Can I use one self sealing lid jar (using in the commercial) to can in the pressure canner? As there is no right information regarding on this type on one lid self sealing jar.
Thanks
C
Thanks for the insightful article. Any updates since on one piece lids for hot water canning? Specifically plastisol lined lug lids. Thanks in advance!
Healthy Canning
As of 2020, we have heard nothing about any funding being provided either to the “National Center for Home Food Preservation” nor to any extension service to do any testing on one-piece lids — let alone much of anything!