Carefully can tomatoes to avoid spoilage and food poisoning. Some tomato plants, even high-acid varieties, produce lower-acid fruits under some conditions. Always add bottled lemon juice or citric acid to avoid the risk of botulism.
• Control spoilage by heat processing filled jars in a boiling water canner or a pressure canner.
• Select only disease-free, vine-ripened firm tomatoes. Do not can damaged or overripe tomatoes. Avoid tomatoes picked from dead vines. They can be lower in acid. Freeze them instead.
• Help to sterilize new canning lids by placing them in a saucepan and simmering them in water.

Crushed tomatoes by hot pack method:
• Peel, remove cores and quarter them.
• Heat rapidly in a large kettle and simmer gently for 5 minutes. Crush with wooden spoon.
• Add two tablespoons bottled lemon juice to each clean quart canning jar, then fill with hot tomatoes.
• Add one teaspoon canning salt.
• Only seal with two-piece canning lids.
• Process quarts jars for 50 minutes in a boiling water bath canner.
• In a dial gauge pressure canner, process for 20 minutes at 6 pounds pressure, or 15 minutes at 11 pounds pressure.
• In a weighted gauge canner, process for 20 minutes at 10 pounds pressure, or 15 minutes at 15 pounds pressure.

Whole or halved raw tomatoes packed in water:
• Add two tablespoons bottled lemon juice to each clean quart canning jar and fill with raw whole or halved tomatoes.
• Cover tomatoes in jar with hot water, and wipe off jar lip with damp paper towel.
• Adjust pretreated lids and screw ring onto jar.
• Process quarts jars for 50 minutes in a boiling water bath canner.
• In a dial gauge pressure canner, process for 15 minutes at 6 pounds pressure, or 10 minutes at 11 pounds pressure.
• In a weighted gauge canner, process for 15 minutes at 10 pounds pressure, or 10 minutes at 15 pounds pressure.

Raw whole or halved tomatoes packed in juice:
(Tomatoes packed in juice need a much longer processing time to prevent spoilage.)
• To each quart jar add two tablespoons lemon juice and one teaspoon salt.
• Fill with peeled raw tomatoes.
• Press to make enough juice to cover, or add previously strained hot juice.
• Wipe off jar lip with damp paper towel.
• Adjust pretreated lids and screw rings onto jars.
• Process quart jars for 90 minutes in boiling water bath canner.
• In a dial gauge canner, process for 40 minutes at 6 pounds pressure, or 25 minutes at 11 pounds.
• In a weighted gauge canner, process for 40 minutes at 10 pounds pressure, or 25 minutes at 15 pounds pressure.