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Water-bath can high-acid foods

A boiling water canner is safe only for high-acid foods such as fruit, pickles, jams and acidified tomatoes. Low-acid foods such as beans, meat and most vegetables need a pressure canner (living-10).

How

1. Check the food is high acid. USU Extension explains that below pH 4.6 the spores that cause botulism cannot grow. Suitable foods include fruits, pickles, sauerkraut, jams, jellies, marmalades and fruit butters.
2. Always acidify tomatoes, whether you water-bath or pressure can them (NCHFP). Add 1 tablespoon of bottled lemon juice or 1/4 teaspoon of citric acid per pint jar.
3. For quart jars of tomatoes use 2 tablespoons of bottled lemon juice or 1/2 teaspoon of citric acid (NCHFP).
4. Follow a tested recipe for headspace and time. Example: hot-packed whole or halved tomatoes take 40 minutes for pints and 45 for quarts at up to 1,000 ft (NCHFP).
5. Keep water at least 2.5 cm (1 in) above the jar tops. Start timing only when the water boils hard, then hold a gentle boil (USU).
6. Add time for altitude (USU). Add 5 minutes at 1,001 to 3,000 ft (305 to 914 m) and 10 minutes up to 6,000 ft (1,829 m). Add 15 minutes up to 8,000 ft (2,438 m) and 20 minutes up to 10,000 ft (3,048 m).
7. Lift jars out with a jar lifter and cool them at room temperature, 2.5 cm (1 in) apart and out of draughts (USU).

Safety: Botulism from badly canned food can kill. Never water-bath can low-acid foods such as beans, corn, meat or plain vegetables; pressure can them (living-10). Never skip the acid in tomatoes. Discard jars that bulge, leak or spurt.

Do these first

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Sources

1. Principles of boiling water canning. Utah State University Extension, accessed 2026-11
2. Preserving food: canning tomatoes and tomato products. National Center for Home Food Preservation, University of Georgia, accessed 2026-11

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