Excerpt from the Popular Kitchen Series magabook Canning & Preserving with permission from its publisher, BowTie magazines, a division of BowTie Inc. Purchase Canning & Preserving here.
Ascorbic acid: vitamin C in powdered form; used to prevent discoloration of light-colored fruits; can be purchased at a pharmacy.
Bacteria:naturally occuring microorganisms that can spoil food.
Blanch: briefly cooking produce in boiling or steaming water, then plunging it into ice-cold water to stop the cooking process and preserve the color.
Boil: to heat a liquid to the point that bubbles appear, and to cook food in boiling liquid. Water boils at 212 degrees Fahrenheit at sea level.
Boiling-water canner: a device that sterilizes canned food so that it can be preserved without refrigeration. Many boiling-water canners consist of a pot, lid and wire rack to hold glass jars.
Cheesecloth: a loosely woven cotton cloth originally used in cheesemaking; often used for other culinary purposes such as straining and lining.
Chutney: a food that has as similar consistency to jelly and relish, contains fresh ingredients – such as herbs, fruits, spices and sugar – that are combined and slowly simmered; often used as a sweet condiment with a light vinegar flavor, although some chutneys also can be spicy.
Citric acid: juice from citrus fruits, such as lemons; used to increase acidity in recipes and to prevent discoloration of fruits and vegetables.
Citrus press: a device used to squeeze juice from the citrus fruits.
Clostridium botulinum: a harmful bacterium that triggers botulism, a food-borne illness that can be deadly.
Conserves: a jamlike preserve made from fruit steeped in heated sugar mixture for a short period of time.
Fermentation: a process in which carbohydrates are converted into alcohol or acid. Under specific conditions, yeast can convert sugar into alcohol, while in other foods, bacteria ferments and produces lactic acid; pickling relies on fermentation to preserve foods.
Freezer burn: damage to frozen food caused by air exposure, which typically occurs when food has not been packaged properly in air-tight containers. The air dries out the food, causing grayish-brown spots to appear.
Freezing: a method of food preservation in which food is stored at 0 degrees Fahrenheit or below to inhibit the growth of microorganisms and the processes that deteriorate food.
Fruit butter: a fruit spread that is categorized with jams, jellies and preserves. Fruit butter doesn’t require pectin, nor does it contain pieces of fruit, as it is puréed to achieve a butter-like texture.
Headspace: the empty space between a jar’s lid and the food inside. In canning, leaving headspace is required, because the canned food expands during processing.
High-acid: a food with a pH level of 4.6 or less.
Hot packing: filling jars with cooked, heated food before canning.
Jam: preserved fruit pieces, usually of one fruit; the fruit’s juice and pulp is combined with water and sugar and then heated, producing a soft, gelled spread in which fruits aren’t distinguishable and evenly distributed. Jam does not contain liquid.
Jelly: a translucent spread made from filtered fruit juice; jellies are firm and spreadable with a vibrant color.
Juicing: the process of squeezing out juice from fruits or vegetables, often using a juicer or a citrus press.
Low-acid: a food with a pH level of more than 4.6.
Marinate: soaking food in a seasoned, acidic liquid to add flavor. Marinades usually contain vinegar, wine, lemon juice, and spices and herbs.
Marmalade: a sweet preserve that has the translucent quality and consistency of a jelly, and the texture and structure of a jam; contains chopped fruit pieces and peel; traditionally made from tangy citrus fruits.
Oxidation: a process caused by a food’s exposure to oxygen. When food is exposed to air (e.g. a sliced apple), its chemical composition is altered, diminishing the food’s nutritional value, causing discoloration and shortening the food’s shelf life.
Pasteurization: a method of food preservation in which food is heated to slow enzymatic activity and the growth of microorganisms that cause spoilage as well as to kill disease-causing bacteria.
Pectin: a water-soluble gelling agent found in fruit tissue.
Petcock: the valve on a pressure canner that controls the flow of steam.
pH: the measure of the acidity or alkalinity of a solution. Food that has a pH level of 4.6 or less is considered high-acid while food with a pH level of more than 4.6 is considered low-acid.
Pickling: a method of food preservation in which food is soaked in an acidic solution, such as vinegar or brine, to inhibit enzymatic activity and microbial growth that causes spoilage.
Preserves: a fruit spread similar to jam in which pieces of fruit are kept intact.
Pressure canner: a device that uses steam and high levels of heat to process low-acid foods.
Raw packing: filling jars with unheated or raw food before canning.
Reamer: a hand-held device used to extract fruit juice.
Relish: a pickled condiment consisting of finely chopped vegetables.
Root cellaring: storing hardy vegetables in a dark, humid environment.
Salting: a method of food preservation in which salt is packed onto food to create an environment harmful to bacteria and other pathogens that destroy food.
Screw band: a metal screw-on band that goes over the lid of a canning jar to hold it in place during processing.
Sea level: the measurement of land elevation in relation to the average height of the ocean’s surface, which is the halfway point between the mean high and mean low tides. Cooking food at higher altitudes requires different cooking times.
Simmer: to cook food gently just below the boiling point (180 to 200 degrees Fahreheit).
Smoke box: a preservation device – typically used for meats and fish – that dries food. The smoke acts as an antioxidant, which reduces the potency of microorganisms.
Two-piece lid: the flat metal top and metal band that fits on top of canning jars to seal in food.