45 Essential Canning Glossary Terms You Should Know

New to canning and still learning all the lingo? Turn to this canning glossary whenever you come across a term that you don't know.


Alum. Photo © Erin Huffstetler

An ingredient used to add crispness to pickles. The aluminum ions in alum strengthen the pectin of the food to be pickled, thereby creating the desired crispness. Alum is toxic in large doses; and because of this, pickles soaked in alum must be rinsed thoroughly before they are placed in the brine or vinegar that they will be preserved in. Alum is no longer recommended for use in pickle recipes.

Also Known As: Potassium aluminum sulfate

Aspirin/Salicylic Canning

Aspirin. Photo © Erin Huffstetler

An old-­fashioned method of canning in which aspirin (which contains salicylic acid) was added to foods in lieu of heat processing, or as a means of acidify low­-acid foods, so that they could be water-­bath canned (see term #45). Both practices have been deemed dangerous, and the USDA advises against any use of aspirin in canning.

Also Known As: canning powders


Canning Jar Band. Photo © Erin Huffstetler

A metal screw-on band that goes on over top of a canning jar lid. It is used to hold the lid in place during processing​ so that a vacuum seal forms.


Brine. Meredith Heuer/The Image Bank/Getty Images

A salt­ water solution used for pickling foods. Other ingredients, like sugar and spices, can be added to enhance the flavor. 

Brined Pickles

Brined Pickles
Brined Pickles. Westend61/Getty Images

 see Fermented Pickles

Bubble Remover Tool

Bubble Remover Tool. Photo © Erin Huffstetler

A non-­metallic tool used to remove air bubbles from filled canning jars before they are processed. If you don't already own one, a rubber spatula can be used in its place.

Also Known As: bubble freer

Canning Funnel

Canning Funnel. Photo © Erin Huffstetler

A wide-mouth funnel designed to sit on top of a canning jar, so that food can be ladled into the jar more easily and with less mess.

Canning Rack

Canning Rack. Photo © Erin Huffstetler

A metal rack that fits inside of a canner and holds the jars in place during processing.

Canning Salt

Pickling. Westend/Getty Images

see Pickling Salt 

Cold-Pack Method

Cold-Pack Method
Cold-Pack Method. gtaylor57?E+/Getty Images

​ see Raw-Pack Method

Dishwasher Canning

Dishwasher. Photo © Erin Huffstetler

A method of canning in which jars are filled with food and then run through a dishwasher cycle for processing. Since dishwashers do not reach 212 degrees and heat unevenly, dishwasher canning is not one of the USDA­-recommended canning methods.

Fermented Pickles

Fermented Pickles
Fermented Pickles. Kinga Krzeminska/Getty Images

Vegetable pickles that have been placed in a salt water brine and allowed to ferment for up to six weeks.

Also Known As: brined pickles

Finger-Tip Tight

Finger-Tip Tight. Photo © Erin Huffstetler

When a canning jar band is screwed on as tight as your fingers can get it, without exerting any extra force. Tightening a lid beyond this point could cause the lid or band to buckle during processing, and is therefore undesirable.

Also Known As: finger­-tight

Freezer Jam

Freezer Jam
Freezer Jam. apixel/E+/Getty Images

A type of jam made by combining mashed fruit, sugar and pectin. It does not have to be heat processed, but must be kept in the freezer, since it's not shelf stable. A thawed jar will typically keep for up to three weeks in the refrigerator. Note that freezer pectin must be used, instead of regular pectin (it doesn't require heat to gel).

Fresh-Pack Pickles

Pickles. Jamie Grill/Getty Images

Cucumber pickles that have been preserved in vinegar (usually with the addition of spices) and allowed to cure for four to six weeks.

Also Known As: quick-process pickles, refrigerator pickles

Fruit Butter

Crockpot Apple Butter
Crockpot Apple Butter. Photo © Erin Huffstetler

A sweet spread made by cooking down fruit and sugar until it reaches a smooth, spreadable consistency.

Fruit Conserve

Fruit Conserve
Fruit Conserve. William Reavell/Corbis Documentary/Getty Images

A fruit jam made from a mixture of two or more fruits. It usually contains citrus fruit, nuts, ​and raisins.


Headspace. Photo © Erin Huffstetler

The unfilled space left between the top of the food and the lid. It's required to give the food room to expand when it's heat processed and to ensure a proper seal. Different foods require different amounts of headspace; adhere to the guidelines closely. Too much or too little headspace will interfere with the canning process.

High-Acid Foods

High-Acid Foods. Photo © Erin Huffstetler

Foods that contain enough acid to have a pH of 4.6 or lower. Fruits, fruit juices, jams, jellies, marmalades, fruit butters, and most tomatoes are naturally high­-acid foods. Pickles, sauerkrauts, relishes, chutneys, and salsas that include vinegar or citric acid as an ingredient are also considered high­-acid foods.

According to current USDA guidelines, high­-acid foods may be processed safely in a water-bath canner (see term #45).

Note: Modern tomatoes aren't as acidic as they used to be, and must have an acid added to them to be considered a high-­acid food.

Hot-Pack Method

Hot-Pack Peaches
Hot-Pack Peaches. Ronbailey/E+/Getty Images

A method of canning in which foods are brought to a boil, and ladled into jars while still hot. This helps to expel air from the jar, ensures a tighter fill, and contributes to a better seal. Foods that are hot-packed have less tendency to float in the jar, suffer less discoloration and have a longer shelf life. If you'll be water bath canning your foods, the hot-pack method is preferred over the raw-pack method.

Inversion Canning

Inversion Canning. Photo © Erin Huffstetler

A method of canning in which hot foods are ladled into jars, closed and then turned upside down. Since there is no processing time involved, this method of canning is considered extremely dangerous.

According to current USDA guidelines, all home-canned foods need to be processed in a water-bath canner or a pressure canner to remove the risk of bacterial contamination.


Blackberry Jam. Photo © Erin Huffstetler

A thick spread made from crushed fruit. It often includes sugar and pectin. 

Jar-Lid Wrench

Jar Lid Wrench. Photo © Erin Huffstetler

​A tool that's used to remove stuck lids from canning jars.

Jar Lifter

Jar Lifter. Photo © Erin Huffstetler

A tool used to lift hot jars out of a canner.


Apple Jelly. Photo © Erin Huffstetler

A spread made by cooking fruit or vegetable juice with sugar to create a gel. Pectin is often added to assist in the gelling process.

Jelly Bag

Jelly Bag
Jelly Bag. Ian O' Leary/Dorling Kindersley/Getty Images

A cloth bag used to strain fruit pulp from juice when making jelly. It is often used in conjunction with a jelly strainer.

Jelly Strainer

Jelly Strainer. Photo © Erin Huffstetler

A metal stand that's made to hold a jelly bag. The legs clip onto the top of a bowl, so you can strain the juice into the bowl.


Mason Jar Lid. Photo © Erin Huffstetler

A flat metal disk with sealing compound around the inside edge. It is used in conjunction with a screw band to form a vacuum seal during the processing of home-canned foods.

Low-Acid Foods

Kidney Beans
Kidney Beans. Lee Roger/E+/Getty Images

Foods that contain very little acid, and have a pH higher than 4.6. This includes meats (including poultry), seafood, milk, vegetables, broth, and beans.

According to current USDA guidelines, low-acid foods must be processed in a pressure canner.

Magnetic Lid Lifter

Magnetic Lid Lifter. Photo © Erin Huffstetler

A stick with a magnet on the end of it that is used to lift canning lids and rings out of boiling water. Tongs can be used to do the job, but a lid lifter makes the job easier and faster.


Orange Marmalade. Photo © Erin Huffstetler

 A spread made from citrus fruit (oranges, grapefruit, lemons, etc.). It includes small pieces of fruit and fruit peel in the finished product.

Mason Jar

Mason Jar. Photo © Erin Huffstetler

A glass jar designed specifically for home canning. It features a two­-part closure (lid and band) and thick, tempered glass walls that are capable of withstanding high temperatures and years of use.

Also Known As: canning jar

Open-Kettle Canning

Open-Kettle Canning
Open-Kettle Canning. Roman Adams/The Image Bank/Getty Images

A method of canning where the food is brought to boiling, ladled into jars, and a lid and band is applied. The jars are not processed in a water bath canner or pressure canner. Instead, this approach relies on the heat of the food to seal the jar. 

This is not a USDA-recommended canning method. The food isn't heated to a high enough temperature to kill bacteria and mold or seal the jars properly.

Oven Canning

Oven. Photo © Erin Huffstetler

A method of canning in which jars are filled with food and then baked in the oven. USDA testing has shown that bacteria can thrive in oven-canned foods, and the method is no longer deemed safe.

Also Known As: oven preserving

Paraffin Wax

Paraffin Wax. Photo © Erin Huffstetler

A type of wax that used to be melted and added to the top of jars of jam, jelly and other soft spreads as a seal. This method of preserving does not provide adequate protection against toxic molds and is not recommended by the USDA.

Also Known As: canning wax


Pectin. Photo © Erin Huffstetler

A naturally occurring carbohydrate in plants that gives cells structure. It's extracted from fruits — mainly apples and citrus fruits — and used as a gelling agent in jams and jellies. You can buy pectin in powdered or liquid form, or you can make it yourself.


Refrigerator Pickles. Photo © Erin Huffstetler

Preserving food in an acid (usually vinegar). 

Pickling Lime

Pickling Lime. Photo © Erin Huffstetler

A white powder used in older pickle recipes to add crispness. It works by introducing calcium to the pectin of the food to be pickled.

Pickling lime is alkaline ​and must be washed off completely before the food is placed in vinegar. Failure to do so could result in a less acidic pickling solution and create an environment where bacteria are able to thrive. Botulism cases have been linked to this problem; and for this reason, the use of pickling lime is no longer recommended.

Also Known As: calcium hydroxide, slaked lime

Pickling Salt

Pickling Salt. Photo © Erin Huffstetler

A salt product tailored to the needs of pickling and preserving. It does not contain iodine or an anti­-caking agent, like most salts because they are known to cause discoloration and cloudiness in home-­canned foods.

Also Known As: canning salt


Preserves. Photo © Erin Huffstetler

A spread that has been made (preserved) by cooking a fruit or vegetable.

Also Known As: jam

Pressure Canner

Pressure Canner
Pressure Canner. RyersonClark/E+/Getty Images

A large, heavy pot equipped with a locking lid, pressure gauge, safety valve and vent that is capable of reaching 240 degrees Farhenheit — the temperature required to kill bacteria. A pressure canner must be used to process all low-acid foods.

Processing Time

Kitchen Timer
Kitchen Timer. Kristin Duvall/The Image Bank/Getty Images

The length of time that filled jars must be heated in a water-bath canner or pressure canner to kill any bacteria or mold present in the food. Processing times vary by the type of food being canned and the size of the jar being used.

Raw-Pack Method

Raw-Pack Method
Raw-Pack Method. Jeffrey Coolidge/Photo library/Getty Images

A method of canning where you pack jars full of raw, unheated foods, before processing them in a water bath canner or pressure canner. This is an accepted method of canning but is usually reserved for vegetables that will be processed in a pressure canner.

This approach leaves more air in the jar than the hot-pack method, which may cause the food to float to the top of the jar, and could cause food discoloration over time.


Relish. Photo © Erin Huffstetler

Chopped fruits or vegetables cooked in a seasoned vinegar solution until they are pickled. Relish can be sweet, sour, spicy or mild in taste, and often includes hot peppers in the mixture.

Water Bath Canner

Water Bath Canner
Water Bath Canner. Sara Sanger/E+/Getty Images

A large pot used for canning, which comes equipped with a rack for holding jars and a lid. It is designed to be deep enough for the canning jars to be completely covered with boiling water while they are being processed.

Also Known As: boiling water