Canning surplus ripe tomatoes from the garden makes sense for the budget conscious. Canned tomatoes are good eaten alone, served hot or cold, as a base for soups, or combined with dishes made with dried beans, lentils, or macaroni.
Home canning requires time, patience and skill. I recommend it only when the freezer is full and time permits. The first attempt is the hardest. After that, you can bask in the glow of satisfaction.
How Home Canning Preserves Food
In home canning, food is preserved by heating it in jars at a temperature high enough, for a time long enough to destroy spoilage organisms (yeasts, molds and bacteria). The tightly sealed containers then keep microorganisms out.
Tomatoes, like fruit, may be canned safely in a boiling water canner (boiling water bath).
Canning, like most jobs, goes easily if you plan the steps:
- Assemble equipment.
- Select and wash fresh tomatoes.
- Prepare tomatoes while sterilizing jars.
- Pack tomatoes in suitable jars, adding acid if needed.
- Put lids and screw bands on jars.
- Process jars in boiling water for the correct period of time.
It helps if you make a work plan on paper and arrange a time when you can have the kitchen area for your own use.
Assemble the Equipment
Borrow or buy a canner with a lid. If buying, be wary. Be sure the canner is high enough to allow for a rack in the bottom, quart jars standing upright, and another 2 inches above the jars where boiling water can roll freely.
You can use a large stockpot if it meets these specifications but you must make a rack for the bottom to support the jars and permit circulation of water. A flat-bottomed canner is necessary for some electric ranges.
Locate the jars:
Use only standard mason jars. These are made of a heavier weight of glass than pickle jars and are less liable to break. Discard any with chips or cracks. Wash jars in hot sudsy water and rinse well.
Buy jar closures:
Lids presently in use consist of a flat metal lid that is held in place during canning by a metal screw band. The flat lid is crimped around the bottom edge to form a trough which is filled with a compound that softens and flows slightly during canning to cover the sealing surface, yet allows air to escape from the jar during heating. This gasket (lid) forms an airtight seal as the jar cools after the canning period (processing). Read lid manufacturers instructions and follow these carefully. The metal band of rings may be used again, but the flat lids must be purchased new.
Other Utensils and Supplies
- A strong jar lifter (seven quarts are a heavy load if you attempt to lift them in the wire rack.)
- Funnel for filling jars.
- Wire basket for dipping tomatoes.
- 2 large bowls (or saucepans) for the dipping.
- A clean chopping board, sharp knife, long handled spoon.
- Large stainless steel or enamel saucepan.
- Lemon juice and salt.
- Kettle for boiling water.
Raw Pack or Hot Pack – Your Decision!
Raw pack (cold pack) means that skinned raw tomatoes are packed into jar and covered with hot tomato juice or boiling water. This is quick and easy but the results may disappoint. Raw tomatoes contain a lot of air. During canning, the raw tomatoes shrink and float to the top – It’s safe but not appealing. Hot pack means filling jars with tomatoes that have been skinned, cut in pieces and heated to boiling in their own juice. This permits more food to be packed into each jar.
Use your organizing ability on hot pack
Arrange work to flow in an assembly line fashion:
- Check and wash jars.
- Assemble needed equipment.
- Pick tomatoes not more than 6-12 hours before canning. Do not use tomatoes with cracks, bruises or blemishes. Wash tomatoes carefully.
- Fill the canner half full or water. Put it over the heat. Jars lowered into the rack for sterilizing should be partially full of water. Bring water in canner to a boil, boil 10 minutes.
- Meanwhile, skin tomatoes by first dipping them (in the wire basket) into boiling water in a bowl or saucepan for 30-60 seconds, then promptly dipping them in cold water. The skins will slip off easily.
- Cut tomatoes in quarters – heat some of these in a large kettle to form their own juice. Add more tomatoes to achieve quantity needed, 7 quarts.
The Final Steps:
- Take sterilized jars from the canner using the jar lifter. Place jars in folded newspaper or soft towel to prevent cracking.
- Measure 2 tablespoons (25 mL) of lemon juice into each jar. Add 1 teaspoon salt (5 mL) to each jar for flavor if desired.
- Using the funnel, fill jars, one at a time with hot tomatoes, leaving a space of 1 inch (2 cm) at the top (headspace)
- Remove air bubbles by sliding the plastic spatula around between glass and food inside jars.
- Wipe off the top edge of jar carefully!
- Follow manufacturer’s instructions for using snap lids (usually placing lids in hot water for five minutes to soften the sealing compound). Then position the lid carefully on the jar rim.
- Fit the screw band over the lid and tighten with fingers. Excessive tightening will prevent the exhaustion of air form the jar and prevent proper sealing of the jar.
- Heat water in canner again while loading filled jars. The water level should be 1 inch (5 cm) above the top of the jars. After the water reaches a good rolling boil, start timing – process pint jars 35 minutes process quart jars 45 minutes.
- Maintain a good rolling boil during processing.
- Remove the jars from the canner with the lifter. Place the jars on a wooden board or layers of newspaper. Leave space between jars as they cool. Turn off heat under the canner.
- Do not tighten screw bands! As the jars cool the contents contract and the lid is pulled against the jar to create a vacuum. A plunk of snap noise is made as the lid curves downward, a sign of good sealing.
- Altitude Adjustments – Increase processing time:
5 minutes for 3000 feet
10 minutes for 6000 feet
15 minutes for 8000 feet
- After 24 hours, label the cooled jars and store them in a cool place. If a jar has not been sealed properly, it may be processed again using a new lid. Another solution is simply to make a tomato jelly salad or tomato soup.
Congratulations! Mission Accomplished!
By Emmie Oddie, Home Economist