Home canners understand the value of food preservation and preventing waste, and many undertake the practice as a way to not only be prepared for tough times, but also to save money upfront.
Nonetheless, at-home canning, of any kind, has its own associated costs. Clever and frugal folks are always looking for ways to cut expenses where they are able, and the nickels and dimes really add up over time.
Probably the biggest ongoing cost associated with canning aside from food is the jars and lids. This begs the question of whether or not it is possible to reuse your canning lids. If it’s possible, is it actually safe?
No, standard canning lids are not safely reusable. Typical canning lids are designed to be used once only in order to achieve a secure, airtight seal. Re-use might be possible, but degradation of the sealing compound means a far greater risk of spoilage.
When it comes to canning, some individuals believe that they can get away with reusing lids or grew-up learning to do so from the person who taught them.
However, this is not wise as the practice is just not safe. There is a lot to know about canning in general, including plenty of reasons why reusing lids is not a good idea. Keep reading and I will tell you all about it…
Why Isn’t it Safe to Reuse a Canning Lid?
Simply put, re-using canning lids can lead to spoiled or contaminated food. When re-used, the weakened seal on a lid may allow air and bacteria to enter and then flourish in the canned goods spoiling them.
This risk of contamination from dangerous bacteria makes the canned goods unsafe for consumption. Food poisoning can easily result from this and is something you don’t want to risk.
A Canning Jar Lid is Usually Not One Piece
The usual lid arrangement for mason-type canning jars is composed of two pieces that, working together, form the lid and a secure seal over the jar and its contents. These parts are the disc and band.
The band, a threaded metal hoop mates with the threads on the neck of the jar and keeps the disc pressed firmly in place atop the jar’s rim. The disc itself is a flat sheet of thin metal with a wax-like substance on its underside.
This substance, being a sealing compound, melts during the canning process and forms the airtight seal that is so vital to the success of the operation.
Of these two parts, it is the disc that is a “one-shot” item, and the part that will fail and let you down if reused.
A Re-used Disc May Work, but Is Likely to Fail
To clear the air, it is indeed possible for a twice-used disc to function more or less normally during canning. It will still likely form an airtight seal on the jar, and it will still be leakproof and appear for all the world like a completed, sealed jar you usually turn out.
In fact, it might even be entirely sufficient for common kitchen purposes, just not for long-term storage of canned food.
For instance, if you reuse a disc on a jar of herbs, brine, oil, vinegar and the like it will work fine.
It will keep enough air out that your food stays fresh, and these are items you are going to be opening and closing on the regular anyway.
But this is not the case for proper canning. Despite the fact that many canners have reported successful experiences with reusing discs, I cannot recommend this practice as it is not reliable enough to ensure safety.
A compromised seal can lead to spoilage, or even worse problems like the development of the botulism toxin (Clostridium botulinum) in some cases!
Why Do Discs Fail When Reused?
When it comes to why discs fail, the answer is simple. A disc works during canning thanks to that ring of wax-like sealing compound I mentioned above.
After a disc is heated, cooled and then removed its sealing compound loses the ability to reliably reseal a jar effectively when put through the process again.
Given the low cost of replacement, it is not worth taking chances by reusing old canning lids. Just buck up and buy new ones unless you are truly desperate or are willing to lose your harvest.
Can New Sealant Be Put On Used Discs?
Without a doubt, it is possible to do this. But practically speaking, it is a foolish idea for a couple of reasons…
First, the process would be highly tedious and messy. Second, the new sealing compound won’t stick and form as effectively to the metal lid when you do it as it would when applied at the factory where it was made.
Third, the sealing compound is not a simple wax but a compound designed especially to bond with metal and glass when heated.
Lastly, if you’re messing around with getting any replacement compound, you are better off spending the money on new lids, and problem solved!
Also, know that applying sealant at home will not deliver the same reliability as a factory-fresh disc.
Even if you can spread it evenly and thinly enough, which is highly unlikely given its consistency, there’s no way to guarantee its performance when the moment of truth comes and you complete the canning process.
You Can Reuse Part of the Lid
I know this is a major downer for some of you, but cheer up: You can, in fact, re-use one part of the lid. You can re-use the metal band!
Those metal bands that secure the discs are very durable and long-lasting, so you won’t have to replace them often.
Though they will eventually wear out from the pressures of canning over time, you won’t need to be buying new ones often.
Bottom Line: Use a Fresh, New Disc Every Time
If you want to cut to the chase, I will tell you to use a brand-new disc every time you close up a jar.
I know there is something of a shortage at the moment, but even so they are pretty cheap, and the extra assurance that your goods will keep is worth the few cents. New discs mean happy returns.
But, if you are dead-set on saving money on lids one way or the other, keep reading as I have some tips for you.
Invest in Reusable Lids to Reduce Waste and Save Money
Let’s say you’ve plain had it with one-use discs. You are bound and determined to re-use your lid components and you aren’t going to take no for an answer.
But you also don’t want to risk mass spoilage through re-use. Is there anything you can do?
Yes, there is: Reusable lids.
Instead of single-use, there are some tried-and-true gasket-style lids that feature a silicone or rubber ring instead of a one-use ring of sealing compound.
These advanced canning lids can be adapted to typical mason jars, and are a feature of some European-style jars, often permanently attached on a hinge.
These lids don’t require you to buy new ones for every batch and can be reused until their solid seals start to eventually wear out.
Depending on the type and brand, reusable lids may come in two or three-piece options and you can still find some one-piece designs.
To use your existing jars with such a lid, you need only buy the compatible lids separately. It is also possible to buy a set of jars that come with reusable lids.
Always Inspect Jars and Lid Components
Using new discs or not, you should know that the disc might not be the reason why a can loses its seal and spoils (though it is a common one).
If your components are old or well-used, the metal bands may be corroded or compromised, making it hard to secure a good seal with the disc in the first place.
Additionally, worn threads on both bands and jars can make tightening them enough to hold dodgy.
And you should never forget that sometimes a brand new jar, band or disc could simply be defective, preventing proper performance.
Take the time to give each part of the process a once-over and be on the lookout for damage or irregularities.
And as long as you are inspecting things, take a good look at the jar after canning and cooling, too.
If it is properly sealed, the lid should be sucked down tight to the brim of the jar. (This is called ‘buttoning’). If the seal isn’t buttoned-down, or if the jar is leaking, the lid probably wasn’t firmly secured or it was not a good seal.
In such cases, your only option is to throw away the contents and start over. This is why some folks like to can test batches of components with a single lid or two – so they don’t waste all their hard work if something goes wrong!
Tom has lived and worked on farms and homesteads from the Carolinas to Kentucky and beyond. He is passionate about helping people prepare for tough times by embracing lifestyles of self-sufficiency.