alum Until recently, a common ingredient in pickling recipes. It has been found to cause stomach problems.

antioxidant Keeps food from browning. Examples include lemon and lime juice.

bacteria Organisms that may be harmful if not destroyed properly. Any low-acid recipes must be processed in pressure canners to 240°F for a specific length of time.

blanch A fast bath in boiling water, usually followed by an ice or cold-water bath. Prepares many fruits and vegetables for preserving.

boiling-water canning Process requiring jars be completely immersed in boiling water for a set length of time in order to bring the food to 212°F and create a vacuum seal on the lids.

botulism A toxin that may grow in foods that haven’t been properly processed (allowing bacteria to reproduce). Canning and preserving methods strive to eliminate these toxins by removing air and the use of acids and high temperatures that kill spores.

brine A mixture consisting primarily of salt and water, used in pickling.

candying Encrusting with sugar, often through the use of boiling syrup. A common method of preserving fruit rinds and ginger for baking purposes.

canning salt A fine salt with no iodine or anticaking ingredients that can discolor vegetables.

cheesecloth A cloth used to strain pulp or juice, especially for jelly making. It’s also useful in pickling for holding spices unwanted in final jars.

chutney A slow-cooked blend of fruit, vegetables, spices, and/or vinegar.

cold pack A canning process in which fruits and vegetables go into the jar raw. Afterward, some type of canning liquid is added (usually hot) and the jars processed.

conserve Jam-like spread, often using two or more fruits, and possibly including nuts.

crisping agent Sometimes called Pickle Crisp. A commercial product used to keep pickles fresh in lieu of alum.

dial gauge Part of pressure canner that shows what pressure level the canner has reached.

fermentation A method of preserving food by introducing yeasts. Unanticipated fermentation can indicate other micro-organisms that can cause sickness.

gelling point A temperature of 220°F brings various liquids to gel.

headspace Amount of room left between the top of the food and the lid in a canning jar. This room is necessary to create a vacuum seal.

high-acid food Food with a pH value of 4.6 or less, like tomatoes and many fruit juices. Can be processed using boiling-water methods.

hot pack A form of canning where food goes into the jars hot to be processed.

jam Crushed fruit and sugar (sometimes nuts) processed together into a spread.

jelly A firm spread made from juice and sugar to which pectin may be added.

low-acid food Foods with a pH higher than 4.6. Examples include most seafood, meat, and vegetables. These foods must be pressure canned, heated to 240°F.

marmalade A spread that includes fruit and peel pieces mingled into a jelly base.

pectin A fruit and vegetable carbohydrate frequently used to make jelly, jam, and other spreads.

pickling A preservation process that uses vinegar with spices and water. Foods are processed in hot-water canners.

preserves A spread that preserves fruit in sugar syrup. The fruit retains its shape.

pressure canning A process used on low-acid foods that cooks them to 240°F throughout, killing bacteria.

processing Heating canning jars to specific temperatures for a specific amount of time to kill bacteria, mold, and yeast. Also creates the vacuum seal on canned foods.

raw pack Filling jars with unheated meat or fish prior to processing.

relish A blend of diced vegetables or fruits in a seasoned vinegar solution.

reprocessing Removing and reheating the lid, cleaning and reheating the jar, and reheating the food inside the jar according to the recipe, followed by processing again, to try to save food when the jar doesn’t seal properly.

smoke curing A way of preserving food by smoking it. Also adds flavor to the preserved item.

syrup A blend of sugar and other liquids used to cover ingredients in a jar before processing.

venting Heating of canning jars to force the air out.

weighted gauge A on pressure canners consisting of weights, normally for 5, 10, and 15 pounds of pressure, which go on top of a valve. When the weight rocks, the right pressure has been achieved.