Glossary

Glossary: Home Canning Terms Explained in Plain English

Canning words get used loosely, and some of the mix-ups matter. This glossary explains the words used on this site in plain English. It says where each explanation comes from.

by the editorial team Last checked against sources November 2, 2026 2 min read

The words below are in A to Z order. Each one explains the word only. For processing times and recipes, use a tested source and your manual. For short answers, see questions and answers.

If you are new to all this, what a pressure canner is and low-acid foods are good places to begin. The overview of all machines sorts the kinds.

Which mix-ups cause real trouble?

The guide to electric canner types goes through them with the machines.

Pressure canner and pressure cooker. On Amazon, "pressure cooker" also covers canners, and many titles use both words. The National Center says its advice does not apply to electric multi-cookers, so the difference matters.
A quart of capacity and a quart jar. The size on the box is the size of the pot. A 4-quart cooker does not hold four quart jars. A 23-quart canner holds seven quart jars, says Presto.
Electric canner and electric pressure canner. The Ball EasyCanner and many no-name units are plug-in and have no pressure at all.
Electric stove and plug-in canner. "Pressure canning on an electric stove" means a stovetop canner on an electric range. That is not a plug-in machine.
Approved and listed. The USDA and the National Center publish tested steps. They approve no equipment. ETL and UL are electrical safety marks, not food-safety claims.
A maker's claim and an expert's statement. When a box says a machine follows USDA guidelines, the maker is the one saying it. K-State says Presto's round badge was made by Presto.
Heat and pressure. The USDA says heat held for long enough kills germs. The National Center stresses the heat inside the jars. A sensor in a canner does not measure heat inside your jars.
Four quart jars and a proven process. The National Center lists size along with venting and keeping the canner at the right pressure. Holding four quart jars is one of several conditions. It proves nothing about heating up, holding and cooling down.
A canning button and a canner. A button shows what a menu offers. The National Center's 2019 statement covers multi-cookers that have one.
Smart canner. This is a product name used by NESCO and Carey. It is not a kind of machine. See what the experts say about plug-in canners.

One more that sounds alike. The National Center's warning about multi-cookers leaves out the older Ball Automatic Home Canner, for high-acid foods only. Do not carry that over to the newer Ball water bath machine.

Air vent/cover lock: Presto's name for a small part in the cover that lets air out and shows there is pressure inside. Presto says it also keeps the cover from being opened under pressure. Other canners may differ, so follow your manual.
Botulism: A deadly kind of food poisoning that can come from germs growing in canned food, says the USDA Complete Guide. The CDC names home-canned vegetables as the most common cause of botulism outbreaks in the US.
Clostridium botulinum: The germ behind botulism. The USDA says it is heat held for long enough that kills germs, not the pressure itself.
Combination cooker-canner: A plug-in machine sold for both pressure cooking and pressure canning, such as the NESCO NPC-9. Penn State Extension says it cannot recommend these, because research on their safety is missing. Penn State names no brand. Putting a model in this group is our reading.
Dial gauge: A pressure gauge with a needle on the lid of a stovetop canner. The National Center for Home Food Preservation says to have it checked once a year.
Electric multi-cooker: A plug-in pressure cooker with many settings, such as an Instant Pot, sometimes with a canning button. The National Center does not support USDA canning steps in these. The CDC says not to use them to can low-acid foods (vegetables, meat, chicken, fish).
Electric pressure canner: A plug-in canner made just for pressure canning jars, with its own heater and automatic controls. It is not the same as a plug-in pressure cooker or a plug-in water bath canner. The USDA doesn't approve any canner.
Electric water bath canner: A plug-in pot that heats jars in boiling water with no pressure, such as the Ball EasyCanner. It is for tested recipes for high-acid foods (jam, most fruit, pickles). The CDC says boiling water does not protect against botulism in low-acid foods.
ETL listing: A product safety mark, such as the "ETL Approved" line on NESCO's NPC-9 product page. It is not a food-safety claim. It says nothing about whether the food in your jars was canned correctly.
Extension: Your state's university extension office, which gives free local food-safety advice, such as Penn State, K-State and NDSU. The CDC names them as reliable canning sources. The USDA and CDC say many county offices check dial gauges.
Gasket: The rubber ring that seals a canner's lid to its body. Presto calls it a sealing ring. The USDA says nicked or dried gaskets let steam leak. The All-American canner seals metal to metal and has none.
Headspace: The empty space between the food and the lid in a jar. The USDA says it is needed for expansion during processing and for a seal as jars cool. This site gives no headspace amounts, so take them from your tested recipe.
Low-acid food: Food that is not very acidic: red meat, seafood, poultry, milk and all fresh vegetables except most tomatoes, says the USDA. It says these must be canned in a pressure canner.
Overpressure plug: A rubber safety plug in the cover of a Presto canner. Presto says it pops out and lets steam escape if the vent pipe is blocked. It should be replaced each time the sealing ring is. All-American canners have one too.
PSI: Pounds per square inch, the unit for pressure. The USDA says it is the heat, not the pressure itself, that kills germs. The National Center stresses that the heat inside the jars decides safety, not the pressure reading.
Regulator: A part that sits on a canner's vent pipe. NESCO's guide calls it a jiggler. Presto says its 3-piece regulator controls the pressure. It says the one-piece regulator on its dial canners is a safety part. NESCO's NPC-9 guide uses two regulators, depending on altitude.
Temperature sensor: The part Presto says its digital canners use to run the process instead of a gauge. A sensor in the canner does not measure heat inside your jars. Presto has not published its jar data.
Tested recipe: A recipe with a process worked out for that food and jar. It comes from the USDA Complete Guide, the National Center or a state extension office. This site gives no recipes and links to those sources.
the National Center for Home Food Preservation: The National Center for Home Food Preservation, the US canning experts at the University of Georgia. It publishes canning advice. It approves no canner brand, says K-State Research and Extension.
USDA Complete Guide to Home Canning: The US government's home canning guide, revised in 2015. The CDC names it as a reliable source. It does not mention plug-in pressure canners.
Venting: Letting air and steam escape from a pressure canner before it builds pressure. The USDA says all pressure canners must be vented. How it works depends on your machine, so follow your manual.
Weighted gauge: A stovetop canner control that uses a weight instead of a needle dial. The National Center's tables list different altitude bands for dial and weighted gauges. Use the table that matches your canner.

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electricpressurecanner.com Editorial Team

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We are the editorial team at electricpressurecanner.com. We read manuals, spec sheets and the statements of NCHFP, USDA, CDC and Extension services, and we report who says what, with dates. No lab work happens here, and this site publishes no processing times or recipes of its own.

Manuals and food-safety guidance read
Sources and dates on every page
No lab tests, stated openly
No own processing times or recipes

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