The Home Canning Guide
The Canning Wheel
The Canning Wheel, conceptualized and designed by Container and Packaging, shows which processes should be used with which foods. It also shows you the types of closures that we recommend for those processes.
Hot Bath Canning is the most common home canning processing method. Sterilized and heated glass jars are filled, sealed and submerged in boiling water for a specific amount of time (processing times are usually indicated in each recipe). We recommend lug and twist closures with plastisol for this process.
Pressure Canning involves a heavy, thick pot that is fitted with a steam-venting lid. Jars are placed in the pot with a couple of inches of water, the lid in screwed tight over the top of the pot and the jars are processed in the pressure cooker to temperatures of 240 degrees and higher. This method is typically used for processing meats, poultry and seafood. We recommend high heat lids (often called retort lids). Please contact us for availability of high heat liners and retort lids.
Hot Fill Canning involves filling sterilized jars with a boiling or simmering liquid, sealing the jar with a sterilized one piece lid and inverting the jar (the heat from the hot liquid sterilizes the inner surface of the jar and the bottom of the lid). Unfortunately, while the hot fill method is probably the easiest, it is not as safe hot bathing or pressure canning.
Get the right closure
The longevity of your preserves depends completely on the sealing capabilities of your lid. There are three different types of lids that you should consider for your canning project:
Lug and Twist Closures are metal caps with a non-continuous threading system. These threads are called lugs. These caps only require a 1/4 to 1/2 turn, and are ideal for hot bath processing. These caps are lined with plastisol. Plastisol is a solid material that becomes liquidus when heated properly and forms around the landing of the container. As the jar and cap cool, it begins to cure, or solidifies, which then creates a tight vacuum seal. When removed, a plastisol cap makes a schlurr-pop sound, which indicates a proper seal was achieved. We stock over 20 different colors and sizes. View Lug and Twist Caps.
High Heat Liners (Retort lids) are metal caps with a specialized rubber-based lining that are specifically made for high heat processes. These caps are used in pressure canning and steam canning applications. Container and Packaging does not stock high heat liners, but can get them for you.
Continuous Thread Closures are metal caps with a continuous threading system. These caps require at least a full turn to seal. The plastisol* liners of continuous thread closures has a lower heat tolerance and should not be used for hot bath processing. We stock nearly 25 different colors and sizes. View Continuous Thread Caps.
Start with Clean Jars
You need to sterilize your glass jars before you fill them. You're trying to preserve food from decay, not create a petri dish for decay to multiply in. Combinations of the following three sterilization methods is optimal.
Boil. Submerge glass jars in warm water. Bring to boil. Boil 12 to 15 minutes. Remove and keep warm. Pro tip: Boiling your jars is the most HIGHLY recommended sterilization method for home canning applications.
Bake. Place glass jars in a cool oven. Turn to 225 °F and bake for 20 minutes. Remove and keep warm. Pro tip: Bake freshly laundered towels in a shallow cake pan filled with water to reduce stress on glass and breakage.
Bathe. Submerge glass jars in a weak bleach solution. Let sit for 15 minutes. Remove and keep warm. Pro tip: Use three drops per gallon of water. Best if combined with other methods. Bathtub NOT recommended.
A Few Cautionary Tips
When doing home canning, it's important to remember that you're working with fragile glass, boiling liquids, steam, and heavy objects. Please be cautious. A few thing to remember:
Glass is fragile. Glass can tolerate high heat levels … much higher than most plastic jars. That's why it's perfect for preserving foods. However, treat it gently, both when cool and hot. Glass is solid, but it's also brittle.
Be cautious of thermal shock. Glass needs to warmed up and cooled down. Sudden temperature changes to glass can cause it to weaken, crack or even shatter. A general rule is to not force glass to make sudden temperature jumps of more than 90 degrees. Many canners sterilize their jars (by putting them in warm water, and then bringing them to a boil), then immediately fill them, and then immediately process them in small batches. This allows the glass to gradually get warmer.
Hot stuff burns. A boiling vat of water is hot. Cooked food is hot. Things splash and slosh. Things get sticky and slippery. Use oven mitts, jar-lifter tongs, hot pads, aprons, rubber gloves, long sleeves, and closed-toe shoes. Be careful working with steam.
Dull things cut, too. Keep your knives sharp. They're safer and easier to use than dull knives. Because a dull knife causes you to work harder, the likelihood of cutting yourself increases.
A Quick Disclaimer
We aren't professional canners! Sure, we know a thing or two about canning. We do it ourselves (well, we, the people that work here do).
This Home Canning Guide, is a guide. It is not an authoritative resource for how to process and preserve food. It does, however, attempt to explain the difference between the technical restrictions and specifications of the three different types of food processing lids: continuous thread closures, lug/twist closures, and high-heat/retort lined closures.
These closures should be used as they were intended to use. Don't use a retort liner for a hot fill process. The correct seal will not be achieved.
As with any packaging project … test it. We believe in it so much that we offer samples (and heck, they're so inexpensive, you can even purchase a handful without breaking the bank).
And finally, our lawyers insist that we post our official product disclaimer. Here it is, and happy canning!
DISCLAIMER: Container and Packaging, Inc. assumes no responsibility for suitability of any container or closure for customer's particular use. It is the customer's responsibility to do product compatibility testing with containers and closures selected by the customer. We are not responsible for consequential damages arising from customer's selection and use of containers and closures supplied by us.
A note about sources: Information in this Home Canning Guide has been accumulated over several years by researchers at Container and Packaging. Information has been pulled from professional home canning courses taken from trained professional food preservers, interviewing experienced home canners, personal experience, interviewing official representatives of closure manufacturers, and past articles posted to the Container and Packaging Blog. Container and Packaging claims no responsibility for the validity or lack thereof of the information contained herein.