Food Preservation Classes

— Written By N.C. Cooperative Extension


Beverly Nelson, M.Ed., Family & Consumer Science Agent, teaches classes on CANNING & FREEZING VEGETABLES & FRUITS SAFELY and , MAKING DELICIOUS & SAFE JAMS, JELLIES AND PICKLES.   She has also written this helpful article on canning tomatoes safely.

Canning Tomatoes Safely

It’s that time of year again, when we can those delicious tomatoes from our gardens or from our local farmers’ market.  There’s nothing quite like home canned tomatoes for a healthy, nutritious, tasty addition to any meal.  Plus, it’s so simple to can them safely if you follow a few guidelines.

First, check your canning jars for nicks, cracks, or sharp edges that may keep your jars from sealing or cause them to break.  Always use new canning lids and check your bands for proper fit.

Wash your jars, lids and bands in hot, soapy water and rinse well.    Fill jars with hot water and heat jars and lids in a pan of simmering water, but do not boil your lids.  Leave jars and lids in the hot water until you are ready to use them and take them out one at a time.

Fill your boiling-water canner half-full of hot water.  Put your rack in the canner and heat water until it simmers.  Keep water hot until used for processing.

Chose fresh, ripe tomatoes at their peak of quality and flavor.  Don’t use any tomatoes with cracks, spots or growths.  Wash tomatoes well and drain.  Put tomatoes in a wire basket and lower into a large saucepan of boiling water for 30 to 60 seconds until skins start to crack.  Take out of water and dip immediately into cold water. 

Slip off skins, trim away any green areas and cut out cores.  Cut tomatoes in quarters for canning crushed and quartered tomatoes.   Leave tomatoes whole or half if you prefer, but you must water bath process them for 90 minutes at 1000-3000 feet elevation.  

Remove canning jar from hot water with jar lifter, drain out hot water, and set on a towel.  For both crushed and quartered tomatoes and whole or half tomatoes, add 2 tablespoons of bottled lemon juice or ½ teaspoon citric acid to each quart jar.  Add 1 tablespoon bottled lemon juice or ¼ teaspoon citric acid to each pint jar. An acid such as lemon juice or citric acid must be added to can tomatoes safely.

Crushed and quartered tomatoes are good for soups and sauces and require a processing time at 1000-3000 feet elevation of only 40 minutes for pints and 50 minutes for quarts.  In a pot, crush about 1/6 of the tomatoes with a spoon and add the rest of the tomatoes quartered.  Stir and cook until all tomatoes are added, then boil gently 5 minutes.

For canning whole and half  tomatoes, put tomatoes in a large saucepan and add enough tomato juice to completely cover them.  Boil tomatoes and juice gently for 5 minutes. 

Pack hot tomatoes and cooking liquid in hot jar, leaving ½ inch headspace.  Add 1 teaspoon salt per quart jar or ½ teaspoon salt per pint jar, if desired. 

Remove air bubbles, wipe jar rims, place lid on jar and screw band just until resistance is met.  As each jar is filled, set it on the rack in the boiling-water canner.  Water level must cover the jars and two-piece lids and bands by 1 ½ to 2 inches.  Add boiling water if necessary.

Put lid on canner, bring water to boil, start counting processing time after water comes to a rolling boil.   For crushed and quartered tomatoes, at 1001-3000 feet process pints for 45 minutes and quarts for 50 minutes.  For whole or halved tomatoes, at 1000-3000 feet, process both pints and quarts for 90 minutes.  When processing time is complete, turn off heat, remove jars from canner and set them upright, 1 to 2 inches apart on a towel to cool.  Do not retighten bands.  Let jars cool 12 to 24 hours.  After jars have cooled, check lids for a seal by pressing on the center of each lid.  If lid is pulled down and does not flex, remove the band, wipe off lid and jar with a clean, damp cloth to remove food particles.  Label and store in a cool, dry, dark place. 

Posted on Aug 21, 2009
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