The fact that one-piece lids are available as an option in canning, whether or not they should be used for home food preservation is clear.
You can use one-piece lids for canning, but it is not recommended by the National Center for Home Food Preservation. You should only use them under controlled temperatures. If not closed at the perfect temperature, it traps air inside the jar, causing bacteria to grow.
Now that you know it’s not ideal to use one-piece lids for canning due to potential safety issues, let’s look at why they are on the market and how you can safely use them. This article will also discuss alternatives to one-piece lids.
What Are One Piece Lids, and What Are They Used For?
One-piece lids are the lid of the jar in one complete piece; they are available in both metal and plastic. One-piece lids were initially sold for at-home canning before people realized the possible dangers. They are now more popular for food storage rather than canning.
The disadvantages of one-piece metal lids are that they are susceptible to corrosion and the mouth is generally narrow. You could opt for a plastic one-piece lid if you prefer a wider mouth. Remember that you should never use plastic one-piece lids to process hot jars.
You should use one-piece lids only for storing goods that do not spoil, such as tea bags, sugar, pasta, etc. They are easy to use and allow for simple access to their contents. However, they are less than ideal for proper canning practices, which require a two-piece lid system to ensure proper sterilization.
Why Do Mason Jar Lids Come in Two Pieces?
It would be best if you always used two-piece lids for at-home canning as they offer optimal sealing without worrying about pressure and temperature control. Two-piece lids are simple to use, and it is easy to tell if you seal the lid correctly.
Mason jars are an example of two-piece lids. Their lids have two parts; a flat metal lid and a metal band. These two parts stay in place during processing. People typically used Vacuum systems for canning a while back, but the two-piece lid has since replaced it for home use.
Mason jar lids come in two pieces to form an airtight seal. The lids are corrugated around the bottom edge, creating a trough with a plastisol sealing compound that acts as a gasket. When you heat the jars, the higher temperatures force air out of the jar, forming the airtight seal.
The USDA currently recommends the two-piece lid system for at-home canning.
Do One Piece Canning Lids Pop?
Many one-piece canning lids have a safety button, or dimple, that forms a vacuum after the canning process is complete.
Yes, some one-piece canning lids do pop. They may pop when you process your jars, and the vacuum forms, pulling the lid down and creating a concave shape in the middle. The second instance is when you open the lid; the safety button will pop because you will release the vacuum seal.
When purchasing your one-piece lids for canning, ensure you buy the ones with a safety button in the middle, as this helps with better sealing. If your one-piece lids fail to pop, it’s not a good sign. You most probably failed to process them long enough and could not meet the correct temperatures to affect the vacuum seal.
Can You Use Plastic Lids for Canning?
When canning at home, it is always best to use metal lids. Plastic lids do not have a vacuum seal, so they offer no protection against bacteria when working with heated foods such as jams, fruit sauces, and pie fillings.
You cannot use plastic lids for canning. The canning process involves using a water bath with boiling water because boiling point destroys most bacterial cells. Plastic lids will also melt or become misshapen when exposed to high temperatures.
If you don’t process your jars at a boiling point, this could allow for bacterial spores to grow and may result in the deadly Botulinum toxin forming inside your jar. Plastic lids are great for storage once you open your mason jars and are reusable and easy to clean.
They are also handier than the two lid mason lids, which often separate during the washing process and are more prone to rust over time.
How To Use One-Piece Lids Correctly
Two-piece lids are often in short supply, and sometimes the only option is to use a one-piece lid. Let’s look at how you can safely do this at home.
Please be advised this is not a recommended or approved method of canning.
Process of Canning With One-Piece Lids
- Place your lids in a saucepan, cover them with water, and put them on the stove.
- Bring to a boil. Continue to boil for 10 minutes.
- Using a jar lifter (Amazon Link), remove the lids from the water.
- Screw the lids onto the jar using a towel to prevent your hands from burning. Tighten to the point when you feel the rim make contact with the jar, not tighter
- Place the jars into the water bath for processing.
- Once completed, remove the pot lid and let the jars sit in hot water for 5 minutes.
- Remove the jars from the hot water.
- After some time, the button will pop and look concave; this means you have successfully sealed your jar.
If you doubt that you sealed your jar sufficiently, keep it in the fridge and use the contents as soon as possible.
If you cannot access the recommended two-piece lids for canning, you can use one-piece lids. The best is to purchase one-piece lids with the safety button as they offer a vacuum seal, making contamination less likely.
The USDA does not approve one-piece lids for canning, so be aware of the risks involved. It is best to use these lids for storage rather than canning. If you are canning goods to resell, you should only use two-piece lids as they offer the most secure seal.
For more, don’t miss A Guide to Proper Use of Mason Canning Jars | What Are They Safe For?
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