Canned Tomatoes

1. Wash and rinse jars and bands. About 45 minutes before filling jars fill boiling water bath canner two-thirds full of water; heat to just below boil and keep hot. Place jars in rack set on edge of canner or in 225 F (110 C) oven to heat. A few minutes before filling jars; bring pot of water to boil; boil lids for 5 minutes. Remove from heat; leave in water until ready to use.

2. In large pot of boiling water, blanch tomatoes, in batches, for 30 to 60 seconds or until skins loosen. Remove and chill in cold water; drain immediately and peel. Core and trim away any green, bruised or decayed spots; cut into quarters. In two large pots or in batches, over high heat, heat tomatoes until heated through and juices boil, about 10 minutes.

3. Filling one jar at a time, pack tomatoes and juice into jar, leaving 1/2-inch (2 cm) headspace. For each 4-cup (1 L) jar, add 1/2 tsp (2 mL) citric acid or 2 tbsp (25 mL) reconstituted lemon juice. (For each 2-cup/500 mL jar, add 1/4 tsp/1 mL citric acid or 1 tbsp/15 mL reconstituted lemon juice.)

4. Run spatula around inside of jar, pressing tomatoes to release any air bubbles. Add more tomatoes or juice if needed to maintain 1/2-inch (2 cm) headspace.

5. With clean damp cloth, wipe rim. Cover with lid; screw on band firmly without forcing (fingertip tight). Place in rack set on edge of canner. Lower filled rack into water. Pour in enough simmering water, avoiding tops of jars, to cover jars by 1 to 2 inches (2.5 to 5 cm). Cover canner and bring to full rolling boil. Boil 4-cup (1 L) jars for 45 minutes, 2-cup (500 mL) jars for 35 minutes. Turn off heat.

6. Lift rack to sit on edge of canner. Using jar lifter, transfer jars to towel-lined surface. Let cool completely (some separation of juice in jar is natural). Do not retighten screw bands. Check for seal to ensure lids curve inward and don't move when pressed with finger. Refrigerate any improperly sealed jars; use within 3 days. Store in cool, dark dry place. Refrigerate after opening.

Additional information :

Variations
Raw-Packed Tomatoes: Substitute peeled cored whole or halved raw tomatoes for cooked. Pack into hot jars, pressing firmly to squeeze out juice and eliminate air. Top up with boiling tomato juice. Continue with method for canned tomatoes.

Canned or Raw-Packed Herbed Tomatoes: Pack sprigs of dried thyme along with tomatoes into jars.

Tips
Be sure to can only firm ripe tomatoes, not overripe or soft ones.

It is safe to can tomatoes in a boiling water canner; other vegetables require pressure canning. Don't add vegetables when canning tomatoes; add them when preparing a dish.

Always use new lids. Reuse bands if not bent or rusty. Use jars that are free of nicks and cracks.