If you’ve never preserved your garden abundance by canning, the system can be a little confusing. A friend of mine—one who’s never canned before—was asking about home preservation and I was reminded that although I grew up understanding how a canning jar works, many people just don’t.
The jars most commonly used for home preservation these days come from Ball and Kerr (both made by Jarden Corporation). They are glass and come in a variety of sizes, from small four-ounce containers to half-gallon sized. All of these jars are approved for home canning use except for the half-gallon size (I use the half-gallon size for storing dry goods). The small sizes are good for jams and jellies, especially those that you plan to give as gifts. Jars come in both a standard or wide mouth, referring to the size of the jar’s opening. Wide mouth jars are useful for preserving larger items like peach halves or for pickles that need to be placed in the jar by hand.
Glass canning jars can be washed and reused from year to year. I’ve collected a good quantity of jars over the years by keeping my eyes open at garage sales. If you’re looking for second-hand jars, just remember that jars with chips around the rim should not be used for preservation, as the chip can compromise the seal.
Canning lids are typically metal, a flat disk with a ring of rubber around the perimeter. This rubber ring allows the food to remain sealed inside the jars after processing. Lids come in both standard and wide mouth sizes to correspond with the jars. Jarden rolled out BPA-free lids in early 2013.
Metal canning lids cannot be reused for home preservation. Once a lid has been used, the seal becomes compressed and it will be more difficult to get the necessary airtight seal. (That seal is critical to creating a product that is safe and free of botulism.) You must purchase new lids for each new canning project. Lids are sold in sets of twelve and can be purchased separately from jars and rings.
An alternative to metal canning lids are the plastic lids made by Tattler. These come in two pieces — a plastic disk and a rubber ring. Tattler canning jars are BPA-free and can be reused from year to year.
Metal rings (also called bands) also come in both standard and wide mouth sizes. These are screwed over the lid to hold the lid in place during the canning process. Once your jars have cooled and the lid is sealed, rings are removed and can be used to process another batch of jars. This means that you don’t need as many rings as you have jars. Rings can be reused indefinitely, but they do tend to rust over time.
The jars from Weck are in a category of their own. Both the jars and lids are made from glass, and thus reusable. The sealing ring is rubber and also reusable. The sealing process with a Weck jar requires a couple of metal clips that hold the rubber ring and glass lid in place during processing.
Weck is a European company and while the jars are available on their website, you won’t find them readily available in the USA.