Preserve · field guide
Water-Bath Canning Tomatoes: How-To & Times (2026)
When the tomatoes come in all at once, canning is how you eat your own harvest in January. Water-bath canning is the simplest method to learn, and tomatoes are the classic first project. The one rule you cannot skip is adding acid. Here is why, the exact times to process, and how to fix the two problems every beginner hits.
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Why you must add acid
Tomatoes sit right on the edge of the pH that is safe for water-bath canning. To can them safely you add a measured amount of acid to every jar, every time. This is not optional and it is not a place to improvise.
Use bottled lemon juice, not fresh. Bottled has a consistent acidity; fresh lemons vary too much to trust. Add 2 tablespoons of bottled lemon juice per quart jar, or 1 tablespoon per pint. Bottled citric acid (1/2 teaspoon per quart) works too, and 4 tablespoons of 5% vinegar per quart is a backup if you do not mind the tang.
These times and amounts follow the tested guidelines from the USDA Complete Guide to Home Canning and the National Center for Home Food Preservation. When a recipe is tested, the acid, the pack, and the minutes all work together. Change one and it is no longer safe.
The gear you need
You do not need a pressure canner for high-acid, acidified tomatoes. A water-bath canner is enough, and it is cheaper and simpler to learn on.
- A water-bath canner, or any deep pot with a rack and a lid, tall enough to cover the jars by 1 to 2 inches of water.
- Quart or pint mason jars with new flat lids and reusable bands.
- A jar lifter and a wide-mouth funnel. The two tools that save burned fingers.
- Bottled lemon juice or citric acid for the acid step.
Hot pack or raw pack
Both are safe; they just change the look of the jar. Hot pack simmers the peeled tomatoes for 5 minutes before they go in the jar, which drives out air, keeps fewer jars from floating, and packs more fruit per jar. Raw pack goes in cold and is faster but floats more.
Either way, peel first. A 30 to 60 second dip in boiling water, then a plunge into ice water, slips the skins right off. Add the lemon juice to the empty jar, pack the tomatoes in pressing gently to fill their own juice, and leave 1/2 inch of headspace.
How long to process
Start counting only once the water is at a full, rolling boil with the jars covered by an inch of water. At sea level to 1,000 feet, process for these times, then use the chart below to add minutes for your elevation:
| Jar / pack | At 0–1,000 ft | Notes |
|---|---|---|
| Quarts, whole or halved in water | 45 min | The classic tomato pack |
| Pints, whole or halved in water | 40 min | Same method, smaller jar |
Adjust the time for your altitude
Water boils cooler as you climb, so higher elevations need more time to reach a safe kill. This is the single most-missed step in home canning. Find your elevation and add these minutes to the base time above:
| Your elevation | Add to the time |
|---|---|
| 0–1,000 ft | none (use the base time) |
| 1,001–3,000 ft | +5 min |
| 3,001–6,000 ft | +10 min |
| 6,001–8,000 ft | +15 min |
| 8,001–10,000 ft | +20 min |
Fix the common problems
Two things worry every first-timer, and both are usually fine:
- Floating tomatoes: harmless, just air and the fruit separating from its juice. Hot-packing and pressing the fruit down as you fill reduces it. The jar is still sealed and safe.
- Liquid loss (siphoning): the water boiled too hard, jars were moved too soon, or headspace was wrong. As long as the lid sealed, the jar is safe; use those first, since exposed fruit can darken.
- A lid that did not seal: refrigerate and use within a week, or reprocess within 24 hours with a new lid. Never re-can a jar that has sat out unsealed for a day.
- Cloudy liquid: usually starch or hard-water minerals, not spoilage. Real spoilage looks like bulging lids, spurting liquid, or an off smell on opening. When in doubt, throw it out.
Storing what you put up
Let the jars sit undisturbed for 12 to 24 hours, then check the seal: the lid should not flex when pressed and stays down. Remove the bands, wipe the jars, and store them without the bands so a failed seal is obvious.
Sealed jars keep their best quality for about 12 to 18 months in a cool, dark pantry. Label every jar with the date and eat the oldest first.
Recipe
Ingredients
- About 21 lbs ripe paste or slicing tomatoes
- Bottled lemon juice (2 tbsp per quart jar, 1 tbsp per pint)
- Canning salt (optional, 1 tsp per quart)
Method
- Wash jars and keep them hot. Heat water in the canner.
- Wash, core, and peel the tomatoes (a 30 to 60 second boil then an ice bath loosens the skins).
- For hot pack, simmer the peeled tomatoes 5 minutes; for raw pack, skip this.
- Add 2 tbsp bottled lemon juice to each quart jar (1 tbsp per pint).
- Pack tomatoes into jars, pressing to fill their juice, leaving 1/2 inch headspace.
- Wipe rims, set lids and bands finger-tight, and lower jars into the canner.
- Process quarts 45 minutes (pints 40) at a full rolling boil, adding time for your altitude.
- Cool 12 to 24 hours undisturbed, then check seals.
Keep going
Questions, answered straight
Whole or halved tomatoes packed in water process 45 minutes for quarts and 40 minutes for pints, timed from a full rolling boil at 0 to 1,000 feet. Add 5 to 20 minutes for higher elevations using the altitude chart above.
Plain acidified tomatoes are safe in a water-bath canner. You only need a pressure canner if you add low-acid foods like peppers, onions, or meat, which changes the pH.
No. Taste does not tell you the pH. Every tested recipe adds a measured acid to every jar. Skipping it risks botulism, which you cannot see, smell, or taste.
Yes for whole and crushed packs. Skins turn tough and trap air. Dip the tomatoes in boiling water for 30 to 60 seconds, then into ice water, and the skins slip off.
Floating is just air and the fruit separating from its juice. It is harmless and the jar is still sealed. Hot-packing and pressing the fruit down as you fill reduces it.
Not the flat lids. Their sealing compound is a one-time use, so a reused flat lid may not seal. The metal bands are reusable; the flat lids are not.
Sealed and stored cool and dark, they keep their best quality for 12 to 18 months. They stay safe longer while the seal holds, but flavor and color slowly fade.
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