As can be expected with a product as unique as reusable canning lids, we receive a lot of questions. Here are a few, and our answers, in our effort to help further your understanding of Harvest Guard Reusable Canning Lids.
The lids will last a lifetime, and beyond quite honestly. They are BPA and Phthalate free, and made from a food grade plastic known as Acetal Copolymer, designed to withstand temperatures well beyond what you will find in a safe canning environment. Assuming you don’t exceed recommended temperatures in a pressure canner (240 degrees F), your Harvest Guard Reusable Canning Lids will outlast you!
Yes! While we can’t attest to their actual longevity, due to the varying conditions of use, we can say you should expect at least 6-8 uses per gasket before considering replacement. Much depends on the type of canning being done, and the length of time in storage on sealed jars. A gasket used in for pressure canning, and stored for long periods of time will not last as long as one used in a water bath and opened within a few months of processing. Stronger vacuum created in pressure canned jars, and long periods of storage will compress the gaskets more, keep them compressed longer, and therefore make them want to retain that compressed state faster. That being said, a pressure canned gasket, stored for 1-2 years, will still provide at least 6 uses before stretching to the point of needing replacement.
Additionally, the gaskets are also made from a food grade material, in this case, food grade nitrile rubber. They contain no silicone and therefore not prone to silicone related allergies.
Sorry, they don’t pop… But you will easily know they have sealed once you remove the metal screw band after the jars have cooled. After doing so, simply grasp the rim of the plastic lid with your fingertips and lift. A failed seal will lift easily from the jar without resistance. The same for a jar that loses its seal in storage. A quick check of jars in storage, by gently lifting or running your hands over sealed jars will identify if a seal has failed. It is our experience that once sealed, few jars lose that seal, even after several years.
Interestingly, metal lid manufacturers have recently begun advertising their seals will last 18 months. That doesn’t seem very long to us, as we have jars that remain sealed after many years. In most cases jars processed with Harvest Guard Reusable Canning Lids will remain sealed beyond the time frame considered acceptable to open and consume the contents.
We are often asked how Harvest Guard Reusable Canning Lids differ from single use, metal lids. Since a picture is said to be worth a thousand words, we came up with this simple diagram which shows how our lids and rings are applied to a canning jar.
The key to success is ensuring the metal screw band is not applied too tightly prior to processing, so as not to trap pressure in the jar. It is also necessary to tighten the band, within just a few minutes of removing jars from the canner, while they are still hot, using caution due to the hot contents.
This process will ensure pressure is released properly during the canning process, and allow the vacuum created during cooling to properly seal the jars after removal from the canner.
As always, use extreme caution when handling hot jars of processed food, and if you find a lid that appears “domed up” in the center, allow at least 15 minutes before tightening the metal band as this is indicative of pressure trapped in the jar which can be violently released if handled improperly.
Harvest Guard Reusable Plastic Canning Lids are manufactured using an FDA and USDA approved, food grade plastic generally referred to as Polyoxymethylene Copolymer (POM) or Acetal Copolymer. It is comprised of a BPA and Phthlate free plastic compound that is safe for direct contact with food products and has been used extensively in the food and medical industries since the 1940’s, provided users do not exceed the limitations listed below.
This product is formulated using polyacetal base resin and complies with applicable FDA regulations for food contact applications according to (CFR), Title 21, 177.2470. Any additives, that may be present, comply with appropriate, specific FDA Regulations.
- Types of food: Acetal Copolymer is safe with all types of food except those containing 15% or more alcohol.
- Not recommended for tinctures where alcohol content exceeds 15%.
- Conditions of Use: Use temperature not to exceed 250 deg F per 177.2470.
Additionally, Acetal Copolymer plastic is approved by the USDA for direct contact use with meat and poultry products, and meets the Sanitary Standards 3A Compliance for the Dairy and Food Industries Supply Association (DFISA).
Considering the temperature ranges found in the home food canning environment, and the acceptability of POM by the USDA and FDA for direct food contact, we believe this is the perfect product for home canners. An investment in Harvest Guard Reusable Canning Lids today, means a lifetime of safe, enjoyable canning, and a lifetime of savings.