Canning Terms

This list should help all beginners understand the terms used by Canners….


  • Acetic Acid A pungent, colorless liquid acid that is the primary acid in vinegar (vinegar is 5% acetic acid). Acetic acid is what makes vinegar sour.
  • Acid Any substance in a class of sour compounds.
  • AlumAn ingredient used in older pickling recipes to add crispness and firmness to pickles. Alum, if consumed in large doses, may cause nausea and/or gastrointestinal problems and is no longer recommended for use in pickling recipes. If used, it must be thoroughly rinsed away. The chemical name is potassium aluminum sulfate.
  • Altitude The vertical elevation (distance in feet or meters) of a location above sea level.
  • AntioxidantA substance, such as citric acid (lemon or lime juice), ascorbic acid (vitamin C) or a blend of citric and ascorbic acids, that inhibits oxidation and controls browning of light-colored fruits and vegetables. Antioxidants are believed to neutralize free radicals, harmful particles in your body that can cause long-term damage to cells and lead to disease.
  • Artificial SweetenerAny one of many synthetically produced non-nutritive sweet substances. Artificial sweeteners vary in sweetness but are usually many times sweeter than granulated sugar.
  • Ascorbic Acid The chemical name for vitamin C, a natural, water-soluble vitamin that is commercially available in a concentrated form as white, odorless crystals or powder. It is used as an antioxidant to inhibit oxidation and control browning of light-colored fruits and vegetables.


  • Bacteria – Microorganisms, some of which are harmful, found in the soil, water and air around us. Some bacteria thrive in conditions common in low-acid preserved food and produce toxins that must be destroyed by heating to 240°F (116°C) for a specified length of time. For this reason, low-acid foods must be processed in a pressure canner.
  • Blanch – or scald. A process to loosen skins on fruits and vegetables and kill enzymes prior to preserving. Submerge food in boiling water for amount of time indicated. Then remove and plunge in cold ice water to stop cooking.
  • Boil To heat a liquid until bubbles break the surface. At sea level, this happens at 212°F (100°C). At elevations above 1,000 feet (305 m), the boiling point is reached at a lower temperature. A boil is achieved only when the liquid is continuously rolling or actively bubbling. See also boil gently or simmer or boil, full rolling.
  • Boil gently or simmerTo cook food gently just below the boiling point (180°F to 200°F/82°C to 93°C). Bubbles rise from the pot bottom, only slightly disturbing the surface of the food.
  • Boil, full rollingA rapid boil, usually foaming or spurting, that cannot be stirred down, achieved at a temperature of 220°F (104°C). This stage is essential for attaining a gel when making cooked jams or jellies.
  • Boiling pointThe temperature at which liquid reaches a boil (212°F/100°C at sea level).
  • Boiling Water Bath Canner – Specialized pot used for water bath canning. It comes with a rack to hold jars off the bottom of the canner.
  • Boiling water methodThe fresh preserving method used to process high-acid foods. Heat is transferred to the food product by the boiling water, which completely surrounds the jar and two-piece closure. A temperature of 212°F (100°C) is reached and must be maintained for the time specified by the recipe. This method is adequate to destroy molds, yeasts and some bacteria, as well as to inactivate enzymes. The boiling water method must not be used to process low-acid foods.
  • Botulism – A type of food poisoning that may be fatal. Pressure canners are the only canning method that will reach the high heat needed to prevent it.
  • Bouquet GarniA spice bag, or a square of cheesecloth tied into a bag, that is filled with whole herbs and spices and is used to flavor broth, soup, pickling liquid and other foods. This method allows for easy removal of the herbs and spices after cooking.
  • Brine A salt-water solution used in pickling or when preserving foods. Although salt and water are the main ingredients, sugar and spices are sometimes added.
  • Briney picklesSee fermented pickles.
  • BrowningThe unfavorable color change caused when the cut surface of some fruits and vegetables is exposed to the oxygen in the air. The reaction is called oxidation.
  • Bubble removerA non-metallic utensil used in fresh preserving to remove or free air bubbles trapped inside the jar. To ensure appropriate head space, air bubbles should be removed before the two-piece closure is applied.
  • Bubbling – The process of removing any air bubbles from your jars before applying the lids and rings. This is done to help prevent liquid loss during or after processing.


  • Calcium chloride A naturally occurring salt found in some mineral deposits, used as a crisping agent. The food-safe ingredient is added to the jar before processing, or used in a solution with water as a pre soak. Calcium chloride is used commercially to produce crisp, firm pickles. See also Pickle Crisp® granules.
  • Candy or jelly thermometerA kitchen thermometer that usually comes with adjustable hooks or clips to allow it to be attached to the pan. During the preparation of soft spreads without added pectin, it is used to determine when the gel stage is reached (this occurs at 220°F/104°C, or 8°F/4°C) above the boiling point of water). Always insert the thermometer vertically into the jelly and ensure that it does not contact the pot surface.
  • CannerEither one of two pieces of equipment used in fresh preserving to process jars filled with a food product and covered with a two-piece closure. The two types of canners recommended for use in fresh preserving are a boiling water canner for high-acid foods and a pressure canner for low-acid foods.
  • Canning/preserving liquidAny one of many types of liquids, such as water, cooking liquid, pickling liquid, broth, juice or syrup, used to cover solid food products. Adding liquid prevents darkening of food exposed to the surface and allows for heat penetration.
  • Canning Rack – A shallow rack that elevates your jars slightly off the bottom of the canning pot. It can be a rack designed precisely for this purpose or it can be a round cake cooling rack. Canners use these racks for two purposes. The first is to keep the jars from being in direct contact with the heat of the stove. The second is to ensure that the boiling water is able to be in contact with all facets of the jars.
  • Cheesecloth A loosely woven cotton cloth originally used in cheese making; 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 – A form of acid that can be added to canned foods. It increases the acidity of low-acid foods and may improve the flavor and color.
  • Citrus press A device used to squeeze juice from the citrus fruits.
  • ClearJel®A commercially available modified food starch that is approved for use in fresh preserving. Unlike regular cornstarch, products thickened with ClearJel® do not break down when heated to high temperatures and/or cooled and reheated. ClearJel® can be ordered from online sources or by mail order.
  • Clostridium Botulinum A harmful bacterium that triggers botulism, a food-borne illness that can be deadly.
  • Cold packed – Sometimes called raw pack, means the food is raw when it’s packed in the jars. Hot liquid is added over the raw food. Raw packed is actually a better term. You never want to put ‘cold’ jars in your hot canner. The jars may break.
  • Conserves A jam like preserve made from fruit steeped in heated sugar mixture for a short period of time.
  • Crisping agent – Any one of many substances that make pickles crisp and firm. Some older pickling recipes call for pickling lime, alum or grape leaves to crisp pickles, but these are no longer recommended. Using fresh, high-quality produce, the correct ingredient quantities and a current, tested fresh preserving recipe will produce firm pickles without the addition of crisping agents. The texture of some quick-process or fresh-pack pickles, however, can be enhanced with the use of a product called Pickle Crisp® Granules.
  • Cucumber, pickling – A small variety of cucumber used to make pickles. Pickling cucumbers are usually no more than 6 inches (15 cm) in length. Cucumbers deteriorate rapidly at room temperature and should be stored in the refrigerator and used within 24 hours of harvest.


  • Dextrose – A naturally occurring form of glucose. Dextrose is available as a white crystal or powder and is less sweet than granulated sugar. It is also called corn sugar or grape sugar. Dextrose is widely used as an ingredient in commercial food products. It is found in commercial pectin and produce protectors and functions as a bulking agent or filler.
  • Dial-gauge pressure canner – A pressure canner fitted with a one-piece pressure regulator and a gauge to visually indicate the correct pressure level.
  • Dill – A pungent, aromatic herb that can be used fresh or dried. Fresh dill has feathery green leaves. The most useful dried form is dill seeds. In fresh preserving, dill is primarily used for pickling. One head of fresh dill is equivalent to 1 to 2 tsp (5 to 10 mL) dill seeds or 2 tsp (10 mL) dried dill weed.



  • E. coli – A species of bacteria that is normally present in the human intestines. A common strain, Escherichia coli 0157:H7, produces high levels of toxins and, when consumed, can cause symptoms such as diarrhea, chills, headaches and high fever. In some cases, it can be deadly.
  • Enzyme – Enzymes start the process of decomposition, enzyme action slows in the freezer. Increases between 85 and 120 degrees and stops above 140 degrees. That is why we blanch foods before freezing… it stops the enzymes.
  • Ethylene gas – An odorless, colorless gas that occurs naturally in nature. It is produced by and released from fruits during the ripening process. In turn, the ethylene gas acts as a ripening agent and, when exposed, speeds up the ripening of under-ripe fruits.
  • Exhausting – Removal of air from within and around food and from jars and canners. Blanching exhausts air from live food tissues. Exhausting or venting of pressure canners is necessary to prevent a risk of botulism in low-acid canned foods.


  • 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.
  • Fermented pickles -Vegetables, usually cucumbers, that are submerged in a salt-water brine to ferment or cure for up to 6 weeks. Dill, garlic and other herbs and spices are often added to the brine for flavoring. Fermented pickles are also called “brined pickles.”
  • Firming agent – See crisping agent.
  • Fingertip-tight – The degree to which screw bands are properly applied to fresh preserving jars. Use your fingers to screw band down until resistance is met, then increase to fingertip-tight. Do not use a utensil or the full force of your hand to over-tighten bands.
  • Fresh Preserving – A modern term used to describe the process of preserving fresh produce and freshly prepared foods in glass preserving jars with lids and bands in the presence of heat to destroy microorganisms that cause spoilage. This term is synonymous with home canning.
  • 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.
  • Fruit pickle – Fruit, usually whole, that is simmered in a spicy, sweet-sour syrup until it becomes tender or transparent.
  • Funnel – A plastic utensil that is placed in the mouth of a fresh preserving jar to allow for easy pouring of a food product into the jar. Funnels help prevent spillage and waste.


  • Gasket – A rubber ring that sits along the inside circumference of a pressure canner lid and comes in contact with the base when locked into place. The gasket provides a seal between the lid and the base so steam cannot escape.
  • Gelling agent – Any substance that acts to form a gel-like structure by binding liquid.
  • Gel stage – The point at which a soft spread becomes a full gel. The gelling point is 220°F (104°C), or 8°F (4°C) above the boiling point of water.



  • Head space – The empty space between a jar’s lid and the food inside. In canning, leaving head space is required, because the canned food expands during processing.
  • Hermetic seal – An absolutely airtight container seal which prevents reentry of air or microorganisms into packaged foods.
  • High Acid food – A food or food mixture that contains sufficient acid — naturally or added as an ingredient — to provide a pH value of 4.6 or lower. Fruits, fruit juices, tomatoes, jams, jellies and most soft spreads are naturally high-acid foods. Food mixtures such as pickles, relishes, salsas and chutneys contain added vinegar or citric acid, which lowers their pH, making them high-acid foods. High-acid foods can be safely processed in a boiling water canner.
  • High-methoxyl pectin – A type of pectin that requires a high sugar content and the presence of acid to produce a gel when making jams and jellies. Powdered and liquid commercial pectin products are usually high-methoxyl.
  • Home Canning – The process of preserving fresh or prepared foods in glass jars with two-piece closures, using heat processing to destroy microorganisms that cause spoilage. See also fresh preserving.
  • Hot pack – Filling jars with preheated, hot food prior to heat processing. Preheating food expels excess air, permits a tighter pack in the jar and reduces floating. This method is preferred over the raw-pack method, especially for firm foods.


  • InversionA fresh preserving method in which hot foods are ladled into jars, two-piece closures are applied and the jars are turned upside down (inverted) for a period of time. Since no heat processing takes place, this method is not recommended.


  • 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.
  • Jar – Canning jar sometimes called a mason jar. specially designed to withstand home canning procedures.
  • Jelly A translucent spread made from filtered fruit juice; jellies are firm and spreadable with a vibrant color.
  • Jelly bag – A mesh cloth bag used to strain juice from fruit pulp when making jellies. A strainer lined with many layers of cheesecloth may be substituted. Both the jelly bag and cheesecloth need to be dampened before use.
  • Jelly strainer – A stainless steel tripod stand fitted with a large ring. A jelly bag is placed over the ring. The stand has feet that hold it onto a bowl to allow juice to strain from the bag into the bowl.
  • Juicing – The process of squeezing out juice from fruits or vegetables, often using a juicer or a citrus press.


  • Kosher salt – See salt, kosher.
  • kPa (kilopascal) – A metric unit of atmospheric pressure (force).



  • Liter – A metric unit of volume. One liter is similar in volume to 1 U.S. quart.
  • Lactic Acid – The acid produced during fermentation. The fermentation process converts the natural sugars in food to lactic acid, which, in turn, controls the growth of undesirable microorganisms by lowering the pH (increasing the acidity) of the food product and its environment. Lactic acid also adds a distinctive tart flavor and transforms low-acid foods into high-acid foods that can be safely processed in a boiling water canner.
  • Lemon Juice – Juice extracted from lemons that is added to food products to increase the acidity. Lemon juice can also be purchased commercially. In fresh preserving, lemon juice is added to certain foods to increase acidity and ensure proper processing. In some soft spread recipes, especially those prepared with added pectin, the acid in the lemon juice also aids with gelling. The acidity of freshly squeezed lemon juice is variable, depending on the lemon variety and harvest conditions, whereas bottled lemon juice is produced to consistent acidity standards. In recipes that specify bottled lemon juice, it is crucial for the success of the final product not to use freshly squeezed lemon juice. Where bottled is not specified, either freshly squeezed or bottled lemon juice may be used.
  • Lid – A flat metal disc with a flanged edge lined with sealing compound used in combination with a metal screw band for vacuum-sealing fresh preserving jars.
  • Lime – See pickling lime.
  • Long-Boil Soft Spread – A sugar and fruit mixture boiled to concentrate fruit’s natural pectin and evaporate moisture until a thick or gelled texture is achieved. Long boiling works best with fruits containing naturally high pectin levels. It yields smaller quantities per amount of fruit used and creates a caramelized fruit flavor. It may require a smaller measure of sugar as an ingredient, but the final cooked-down product isn’t necessarily lower in sugar than other products.
  • Low-Acid Food – A food that contains little natural acid and has a pH higher than 4.6. Vegetables, meat, poultry and seafood are all low-acid foods. Bacteria thrive in low-acid foods. The only recommended and practical means of destroying bacteria naturally found in low-acid foods is to heat the food to 240ºF (116ºC) (at sea level) for a specified time in a pressure canner.
  • Low-Methoxyl Pectin – A type of pectin that does not require the presence of sugar to produce a gel when making jams and jellies. No sugar needed fruit pectins are usually low-methoxyl.


  • 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.
  • Microorganisms – Independent organisms of microscopic size, including bacteria, yeast, and mold. When alive in a suitable environment, they grow rapidly and may divide or reproduce every 10 to 30 minutes. Therefore, they reach high populations very quickly. Undesirable microorganisms cause disease and food spoilage. Microorganisms are sometimes intentionally added to ferment foods, make antibiotics, and for other reasons.
  • mL (milliliter) – A metric unit of volume, 1/1000th of a liter. Measures for dry ingredients are available in 1, 2, 5 and 25 mL spoons and 50, 125 and 250 mL dry measures. Metric liquid measures, usually glass or plastic, show levels for quantities divisible by 10.
  • Mold – A fungus-type microorganism whose growth on food is usually visible and colorful. Molds may grow on many foods, including acid foods like jams and jellies and canned fruits. Recommended heat processing and sealing practices prevent their growth on these foods.
  • Mycotoxins – Toxins produced by the growth of some molds on foods.


  • Open Kettle an old method of canning that is no longer recommended. In open kettle canning the foods are boiled and packed into hot sterilized jars. They are then left to cool with no processing. Sometimes turned upside down on their lids.
  • Oven canning/preserving – A fresh preserving method in which jars are placed in the oven and heated. This method is not recommended.
  • Overnight – A period of time from 8 to 12 hours.
  • 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.


  • Paraffin Wax – A pure, refined wax used in an older fresh preserving method. The wax was melted and poured over soft spreads in the jar. It is not a reliable method of preventing contamination by microorganisms, and in many instances mold growth will occur. Since no heat processing takes place, paraffin wax has not been recommended as a safe closure for soft spreads for many years.
  • Pasteurization – Heating of a specific food enough to destroy the most heat-resistant pathogenic or disease-causing microorganism known to be associated with that food.
  • Pectin – A natural substance found in most fruits. This is what causes the jelling of fruits when making jellies or jams. Pectin can also be purchased in both powdered and liquid form.
  • pH (potential of hydrogen) A measure of acidity or alkalinity. Values range from 0 to 14. A food is neutral when its pH is 7.0: lower values are increasingly more acid; higher values are increasingly more alkaline.
  • Pickle Crisp® Granules – A crisping agent that uses calcium chloride, a naturally occurring salt found in some mineral deposits, to enhance the texture of pickles. Pickle Crisp® Granules may be added to jars of quick-process or fresh-pack pickles before processing. Look for it where fresh preserving supplies are sold.
  • Pickling – The practice of adding enough vinegar or lemon juice to a low-acid food to lower its pH to 4.6 or lower. Properly pickled foods may be safely heat processed in boiling water.
  • Pickling Lime (calcium hydroxide) – A white, almost insoluble powder, also known as slaked lime, used in some older pickling recipes to add crispness to pickles. Due to its caustic nature, pickling lime is no longer recommended for making homemade pickles. Failure to remove lime adequately may increase the risk of botulism. Lime can also cause gastrointestinal problems if too much is ingested.
  • Preserve – To prepare foods to prevent spoilage or deterioration for long periods of time. Some methods of preservation are fresh preserving (home canning), freezing, dehydration, pickling, salting, smoking and refrigeration. The method used determines the length of time the food will be preserved.
  • Preserves A fruit spread similar to jam in which pieces of fruit are kept intact.
  • Pressure Canner A specifically designed metal kettle with a lockable lid used for heat processing low-acid food. These canners have jar racks, one or more safety devices, systems for exhausting air, and a way to measure or control pressure. Canners with 20- to 21- quart capacity are common. The minimum volume of canner that can be used is 16-quart capacity, which will contain 7 quart jars. Use of pressure saucepans with less than 16-quart capacities is not recommended.
  • Pressure Canning/Preserving Method – The fresh preserving method used to heat-processs low-acid foods. Low-acid foods must be processed in a pressure canner in order to destroy potentially harmful bacteria, their spores and the toxins they produce. In practical terms, this can be done at 240°F (116ºC). Because the steam inside the canner is pressurized, its temperature can exceed the boiling point of water (212°F/100°C). In a weighted-gauge canner at sea level, the temperature will reach 240°F (116ºC) at 10 lbs (68 kPa) of pressure.
  • Pretreatment – Blanching or treating produce with an antioxidant to prevent browning, slow enzyme action or destroy bacteria.
  • Processing or Heat Processing – Heating filled jars of food to a specified temperature for a specified time to inactivate enzymes and destroy harmful molds, yeasts and bacteria. Heat processing is essential for the food safety of all home-preserved foods. Processing destroys microorganisms that are naturally present in food and/or enter the jar upon filling. It also allows gases or air to be vented from the jar to create an airtight vacuum seal as the product cools, thus preventing re-contamination of the food.
  • Processing Time – The time in which filled jars are heated in a boiling water canner or a pressure canner. The processing time must be sufficient to heat the coldest spot in the jar. The processing time is specified for every current, tested fresh preserving recipe and depends on several factors, such as acidity, type of food product and size of jar.
  • Produce Protector – A commercially available antioxidant that prevents cut fresh produce from browning when exposed to the oxygen in the air, a reaction known as oxidation.



  • Raw Pack – The practice of filling jars with raw, unheated food. Acceptable for canning low-acid foods, but allows more rapid quality losses in acid foods heat processed in boiling water.
  • Re-processing – Repeating the heat processing of filled, capped jars when a lid does not seal within 24 hours. The original lid must be removed and the food and/or liquid reheated as recommended by the recipe. The food and/or liquid must be packed into clean, hot jars and covered with a new, clean lid with the screw band adjusted. The filled jars must then be reprocessed using the preserving method and full length of processing time recommended by the recipe.
  • 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.
  • Salt, kosher – A coarse-grained, textured salt that is free of additives. Kosher salt may be used when making pickles. Because of the variance in density and form, contact kosher salt packers for information regarding equivalencies.
  • Salt, pickling or preserving – A fine-grained salt used in pickling and fresh preserving. It is free of anti-caking agents, which can cause the pickling liquid to turn cloudy, and iodine, which can darken the pickles.
  • Salt, table – A free-flowing, fine-grained salt. Table salt is the most common salt and is used as a table seasoning. It contains additives that may yield unfavorable results when pickling. Iodized table salt (sodium iodide) is not recommended for pickling because it contains an anti-caking ingredient that can make brines cloudy, as well as iodine, which may darken the pickles. Non-iodized table salt can be used for pickling. The pickling liquid may be cloudy, but the pickles will not be dark.
  • Salt, sea – A type of salt produced by the evaporation of sea water. It comes in fine- and coarse-grained textures and is usually more costly than other types of salt. Sea salt should not be used for pickling because it may contain minerals that could darken the pickles.
  • Saucepan, large – An 8- to 10-quart (8 to 10 L) heavy pot essential for cooking soft spreads. The pot must have a broad, flat bottom for good heat distribution and deep sides to prevent food from boiling over.
  • Screw BandPart of a canning lid. This is a metal ring which is screwed down to hold the flat lid against the jar.
  • Scald see blanch
  • 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.
  • Sealing Compound – The red, shiny material, also called plastisol, found in the exterior channel on the underside of the flat metal lid. The sealing compound comes in contact with the lip of the jar and forms a seal when the jar cools after processing.
  • Set Point – 220 degrees. Also known as the gel point. This is what you look for when cooking jam without pectin.
  • Simmer To gently cook just below the boiling point.
  • Skimmer – A metal kitchen utensil that has a long handle attached to a wide, flat surface with perforated holes. Skimmers are used to skim foam from soft spreads after cooking or to drain hot liquid from hot vegetables.
  • 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.
  • Spice bag – A closable fabric bag used to extract spice flavors in pickling solution.
  • Spoilage – the growth of undesirable bacteria, molds and other pathogens that can cause illness, injury or degrade the taste or other qualities of foods.
  • Style of Pack – Form of canned food, such as whole, sliced, piece, juice, or sauce. The term may also be used to reveal whether food is filled raw or hot into jars.
  • Sterilization – The process of killing all living microorganisms. In fresh preserving, this is achieved by heating food in capped jars to a high enough temperature for a length of time sufficient to destroy the most heat-resistant microorganism known to be associated with that food.
  • Storage – A cool, dry, dark place where fresh preserved goods can be kept until ready to be consumed.
  • Straight Walls – Some glass preserving jars possess straight sides that taper downward and allow for expansion during the freezing process. Jars with straight walls can be used when freezing.
  • Syneresis – The separation of liquid from a gel. In fresh preserving, this can happen to soft spreads, usually during storage. It is not a safety concern.
  • Syrup – A sugar water combination used for canning fruits. sweetness levels range from very light to heavy. More sugar = heavier syrup.


  • Thermal Shock Breakage – Stress exerted on preserving jars when glass is exposed to sudden temperature differentials. This stress weakens the glass and can lead to glass breakage, commonly evidenced by the bottom breaking out.
  • Two-Piece Closure – A two-piece metal closure for vacuum-sealing fresh preserving jars. The set consists of a metal screw band and a flat metal lid with a flanged edge lined with sealing compound
  • Two-piece lid The flat metal top and metal band that fits on top of canning jars to seal in food.


  • Vacuum Seal – The state of negative pressure in properly heat-processed jars of home-canned foods. When a jar is closed at room temperature, the atmospheric pressure is the same inside and outside the jar. When the jar is heated, the air and food inside expand, forcing air out and decreasing the internal pressure. As the jar cools and the contents shrink, a partial vacuum forms. The sealing compound found on the underside of fresh preserving lids prevents air from re-entering.
  • Venting – Forcing air to escape from a pressure canner.
  • Vinegar, distilled white – The standard form of vinegar. It is a clear, colorless acidic liquid derived from grain alcohol that possesses a sharp, pungent flavor. Unlike apple cider vinegar or malt vinegar, distilled white vinegar does not compete with the distinctive flavors of herbs and spices in brine. Because it is clear, it does not change the color of white or light-colored fruits and vegetables. In fresh preserving, use 5% acidity (50 grain).
  • Vinegar, cider – A type of vinegar derived from apples that is light golden in color and has a tart fruit flavor. Cider vinegar has a milder flavor than distilled white vinegar. Because it has color, it may darken white or light-colored fruits and vegetables. In fresh preserving, use 5% acidity (50 grain).
  • Vinegar, red or white wine – A type of vinegar derived from wine. The flavor reflects the source of the wine.



  • Weighted-Gauge Pressure Canner – A type of pressure canner that is fitted with either a three- or a one-piece weight unit, both with 5-, 10- and 15-lb (35, 69 and 103 kPa) pressure adjustments. (Only 10- and 15-lb/69 and 103 kPa pressure weights are used in fresh preserving. The 5-lb/35 kPa weight is used for cooking, but not preserving.) Steam, exhausted throughout the processing period, causes the weight(s) to rock, indicating that the pressure level has been achieved or is being maintained.



  • Yeast – Microscopic fungi that causes fermentation.


Please share with us your Terms for Canning and Preserving, (or some we may have forgotten) to add to this master list of definitions for others to learn!!

Sources for Terms and Definitions by Ball, Simply Canning, Canning 101, Pickyourown, Urbanfarmonline,


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