Canning Low-Acid Vegetables

1 Pamela L. BradyExtension FoodsSpecialistCanning is a practical andeconomical way to preserve mostvegetables. By Canning when they areplentiful, we can make the supply lastthroughout the of CanningProcessing canned food that is,heating it after it is in the jar is veryimportant. The heat destroys spoilageorganisms in the food . The tempera-tures required to sterilize differentfoods vary. For safety, each food shouldbe processed by the method and thetime Canning , foods are classifiedinto two groups acid and foodslike fruit, tomatoes,sauerkraut and pickled Vegetables canbe safely processed at the boiling types of organisms that causespoilage in these foods are usually killedat boiling temperatures. Formore infor-mation on water bath Canning , seepublication FSHED77, Water BathCanning of Fruits and foodsinclude allvegetables except tomatoes, meats,poultry and seafood. Most mixtures oflow acid foods and acid foods also arelow in acid unless their recipes includelemon juice, citric acid or vinegar tomake them more acid .

2 Clostridiumbotulinum, the bacteria that causesbotulism, cannot grow in acid foodsbut can grow in Low-Acid ones. Theseorganisms have spores that are veryhard to destroy at boiling water tem-peratures. The higher the canner tem-perature, the more easily they aredestroyed. Therefore, the canner tem-perature recommended for processing Low-Acid foods is 240 F to 250 F, thetemperature in a pressure canner at10 to 15 pounds pressure. At thesetemperatures, the time needed todestroy bacteria in Low-Acid foodranges from 20 to 100 minutes. Theexact time depends on the kind of foodbeing canned , the way it is packed andthe size of the CannerMost pressure canners aredesigned to hold seven quart jars oreight to nine pint jars. Small pressurecanners hold four quart jars; somelarge ones hold 18 pints in twolayers, but only seven saucepans with smallercapacities are not recommended foruse in Canning .

3 Carefully read themanufacturer s directions for yourcanner as different brands differsomewhat in details of trapped in a canner lowers thetemperature obtained and results inunderprocessing. To be safe, all typesof pressure canners must be vented10 minutes before they are OF ARKANSASDIVISION OF AGRICULTUREC ooperative Extension ServiceCanning Low-Acid VegetablesUniversity of Arkansas, United States Department of Agriculture, and County Governments CooperatingArkansas IsOur CampusVisit our web site at: , Youth and 4-H EducationTo vent a canner, leave the vent port uncovered onnewer models or manually open petcocks on someolder models. Heating the filled canner with its lidlocked into place boils water and generates steam thatescapes through the petcock or vent port. When steamfirst begins to escape, set a timer for 10 minutes. Afterventing 10 minutes, close the petcock or place thecounterweight or weighted gauge over the vent port tocause pressure to build up in the models exhaust tiny amounts ofair and steam each time their gauge rocks or jigglesduring processing.

4 They control pressure preciselyand need neither watching during processing norchecking for accuracy. The sound of the weightrocking or jiggling indicates that the canner ismaintaining the recommended pressure and needsno further attention until the load has processed forthe set dial gauges for accuracy before use eachyear, and replace if they read high by more than1 pound of pressure. Low readings cause over-processing and may indicate that the accuracy of thegauge is unpredictable. Gauges may be checked atmost county Cooperative Extension canner lid gaskets carefully, and cleanthem according to the manufacturer s or dried gaskets will allow stem leaks duringpressure operation of the canner. Keep gaskets cleanbetween uses. Gaskets of older canner models mayneed to be lightly coated with vegetable oil once peryear. Newer models are prelubricated and do notbenefit from oiling. Check your canner s instructionsif there is doubt that the gasket on the particularcanner lid you use has been safety fuses are thin metal inserts or rubberplugs designed to relieve excessive pressure fromthe canner.

5 Do not pick at or scratch fuses whilecleaning lids. Use only canners that have theUnderwriter s Laboratory (UL) approval to ensuretheir Jars and ClosuresOnly standard glass Canning jarsshould beused for home Canning . With careful handling youcan use these jars for several years. Jars are made indifferent shapes and sizes and are tempered(strengthened) for heat and cold. You can usually findjars in the following sizes: half-pint, pint, pint andone-half, and size of the jar you choose should bedetermined by the vegetable being canned andthe needs of the family. Examine the sealing edge ofthe jars to see that there are no nicks, cracks orsharp edges that would prevent a seal. Discard anyjars showing these imperfections because they willnot pressure processing is recommended forall Vegetables , sterilizing jars is not necessary. Theywill be sterilized at the time the food is lids consisting of a flat metal lidheld in place by a screw band are only the quantity of lids that will be used in ayear.

6 Although gaskets in unused lids work well forat least five years after manufacture, older gasketcompound may fail to form a follow the manufacturer sdirections in preparing lids for lids carefully. Do not use old, dented or deformedlids or lids with gaps or other defects in thesealing close jars, wipe the jar rim clean. Put on lid,gasket side down. Fit the metal screw band over theflat lid. Follow the manufacturer s instructions fortightening the bands not retighten lids after processing can cause the lids to twist, breakingthe the jars are cool (12 to 24 hours afterprocessing), check the seals. If the lid is depressed orconcave and will not move when pressed, it is bands are not needed on stored jars. Theycan be easily removed after the jars are cooled. Screwbands can be used many times if removed, washed,dried and stored in a dry place. Bands may becomedifficult to remove, often rust, and may not workproperly again when left on stored Small EquipmentIn addition to a pressure canner, jars andclosures (lids), there are a number of small utensilswhich will help you speed up the Canning vegetable brushes, large pans or colanders(for holding/washing food ) and wide-mouth funnelsto fill the jars are a convenience.

7 Long-handled forksand spatulas can be used to lift and pack the bubbles that develop in the packed food can beworked out using a slender spatula or plastic will also need a jar lifter to lift hot jars in andout of the VegetablesSelect only fresh, young, tender Vegetables of avariety suitable for Canning . Gather or purchase onlyas much as can be handled in two to three hours. Workquickly throughout the preparation and Canning . Iffood is allowed to stand, quality is lowered andspoilage is more likely to the Vegetables for size and maturity. Wash incool, running water or lift in and out of severalchanges of water. Avoid soaking. Trim blemishes andpeel, if JarsCorrect packing allows heatpenetration to be uniform andhelps food retain better much solid in the jar willreduce the amount of liquid andretard heating to the center ofthe jar. The manner of packingwill vary with the nature of thefood.

8 Corn, peas and lima beansshould be packed loosely becausethey expand during other Vegetables , make afirm but not tight may be packed into jarswhile it is hot or cold. Regardlessof how the food is packed, anyair bubbles must be can be done by inserting aflat plastic spatula between thefood and the jar and slowly turn-ing the jar as the spatula ismoved up and down. This allows air bubbles toescape. Do not use a metal spatula or knife. Metalmay nick the jars and lead to to Hot Pack1. Wash, prepare and cover Vegetables with boilingwater. Boil for the time listed in Precook only enough Vegetables to fill thenumber of jars which can be processed atone Pack hot Vegetables into clean jars to within1 inch of top of jar (1 1/4 inches for starchyvegetables). Add salt, if desired.*4. Add the hot liquid in which you precooked thevegetable. It contains some of the water-solublevitamins and minerals which dissolved out ofthe food .

9 If it is dark, gritty or strong flavoredor there isn t enough cooking liquid, use boilingwater. Fill to within 1 inch of the top of the jar(1 1/4 inches for starchy Vegetables ).5. Run a narrow spatula between food and jar toremove air bubbles. Clean top of the jar with aclean damp cloth. Process in a pressure canner at 10 to 11 poundspressure (240 F) for recommended to Raw (Cold) Pack1. Wash, sort and prepare Cut into appropriately sized Pack raw Vegetables into clean jars as directedin instructions for that vegetable . Leave 1 inchat top of Add salt, if desired.*5. Fill with boiling water to 1 inch from Run narrow spatula between food and jar toremove air bubbles. Add more liquid if neededto cover food . Wipe threads and sealing edge ofjar. Process in pressure canner at 10 to 11 poundspressure (240 F) for recommended time.*Salt is added to home- canned Vegetables strictly for can be omitted in any recipe.

10 If salt is used, add 1/2 tea-spoon to each pint jar and 1 teaspoon to each in a Pressure CannerFollow these steps for successful pressure Canning :1. Put 2 to 3 inches of hot water in the filled jars on the rack, using a jar canner lid Leave weight off vent port or open at the highest setting until steam flowsfrom the petcock or vent Maintain high heat setting, exhaust steam10 minutes and then place weight on vent portor close petcock. The canner will pressurizeduring the next 3 to 5 Start timing the process when the pressurereading on the dial gauge indicates that therecommended pressure has been reached, orwhen the weighted gauge begins to jiggleor Regulate heat under the canner to maintaina steady pressure at or slightly above thecorrect gauge pressure. Quick and large pres-sure variations during processing may causeunnecessary liquid losses from jars.