Whole tomatoes can be water-bath canned if two conditions are met: every jar is acidified, and you use the processing time that matches how the tomatoes are packed. Miss either one and a sealed lid is not enough to make the jar safe.
Tomatoes sit on the acid line. Many varieties, fully ripe fruit, and fruit from stressed or frost-killed vines can land above pH 4.6 — the point where Clostridium botulinum can grow in a sealed jar. Water-bath canning only works because added bottled lemon juice, citric acid, or 5% vinegar pulls the pH back down. That acid is required even if you later pressure-can the same jars.
The rest of this article follows the tested National Center for Home Food Preservation procedure for whole or halved tomatoes packed in water — the version most people mean when they search this phrase, and the one with the shorter water-bath time.
What “packed in water” actually means
There are three official ways to can whole or halved tomatoes. They are not interchangeable.
| Pack style | What fills the jar | Water-bath time at 0–1,000 ft |
|---|---|---|
| Packed in water | Tomatoes + boiling water or cooking water | Pints 40 min / quarts 45 min |
| Packed in tomato juice | Tomatoes + tomato juice | Pints or quarts 85 min |
| Packed raw, no added liquid | Tomatoes pressed until their own juice fills the gaps | Pints or quarts 85 min |
Using the 40-minute time on a no-liquid or juice pack under-processes the jar. Using the 85-minute time on a water pack is safe but overcooks the fruit. Confirm which pack you are doing before you set a timer.
Water pack is the practical choice for most home canners: shorter heat, easier fill, and tomatoes that still look like tomatoes when you open the jar.
How many tomatoes you need
NCHFP yield averages:
- 7 quarts: about 21 pounds
- 9 pints: about 13 pounds
- 1 quart: about 3 pounds
- 1 bushel (53 lb): 15–21 quarts
Paste types (Roma, San Marzano, Amish Paste) hold shape better. Slicing tomatoes work, but they slump more and give a thinner pack. Any variety can be canned the same way if it is sound and acidified. Do not can tomatoes from dead or frost-killed vines. Do not can rotting or badly bruised fruit. Green tomatoes are more acidic than ripe ones and can be canned with the same acidified process.
Official tested directions call for peeling. Ohio State Extension has also advised against canning whole cherry or grape tomatoes as a separate product because those sizes were not the basis of the original heat-penetration tests. If you use small tomatoes, treat them as tomato halves: peel them, acidify the jar, and follow the water-pack times. Leaving skins on is common in blogs; it is not the tested method.
Acidify every jar — this is not optional
Add acid to the empty hot jar before you pack tomatoes. Measure it. Do not skip it because the tomatoes taste tart.
| Acid | Pint | Quart |
|---|---|---|
| Bottled lemon juice from concentrate | 1 tablespoon | 2 tablespoons |
| Citric acid | ¼ teaspoon | ½ teaspoon |
| Vinegar, 5% acidity | 2 tablespoons | 4 tablespoons |
Use bottled lemon juice, not juice squeezed from fresh lemons. Bottled juice has a consistent acidity; fresh lemons do not. Vinegar is allowed but often leaves a sharper taste. Citric acid changes flavor the least. A pinch of sugar can be added later to soften the acid taste; it does not replace the acid.
Do not cut the acid amount. Do not replace it with “tomato canning tablets.” Those are not a tested acidifier.
Salt is optional: ½ teaspoon per pint or 1 teaspoon per quart. It is for flavor only.
Equipment and setup
You need:
- A boiling-water canner or a deep stockpot with a rack and a lid. Water must cover jar lids by 1–2 inches.
- Canning jars in pint or quart size (tested times exist for those two sizes, not for 24-ounce jars)
- New two-piece lids
- Jar lifter, funnel, bubble tool or chopstick
- Bottled lemon juice or citric acid
- A second pot of boiling water for peeling and for packing liquid
Keep jars hot until filling. Preheat canner water to about 140°F for raw pack or about 180°F for hot pack so the jars do not sit in a long, slow climb to a boil after they go in.
Find your elevation once and write it on the canner lid. Processing time changes above 1,000 feet.
Peel and trim
- Wash tomatoes.
- Score a small X on the blossom end if you want easier peeling.
- Dip in boiling water 30–60 seconds, until skins split.
- Move to cold water.
- Slip off skins, cut out cores, and trim any bruised spots.
- Leave whole or cut in half.
Work in batches so peeled tomatoes do not sit at room temperature for long.
Raw pack or hot pack
Both are approved for water-packed tomatoes, and both use the same water-bath times.
Raw pack is faster on prep day. Tomatoes shrink in the canner, so jars often look less full afterward and may siphon more.
- Add acid (and salt, if using) to hot jars.
- Pack raw peeled tomatoes, leaving ½-inch headspace.
- Cover with boiling water, still leaving ½-inch headspace.
- Slide a bubble tool around the inside. Recheck headspace.
- Wipe rims, apply lids, tighten rings fingertip-tight.
Hot pack takes 5 extra minutes on the stove and usually gives a fuller jar with less siphoning.
- Cover peeled tomatoes with water in a saucepan.
- Boil gently 5 minutes.
- Add acid (and salt) to hot jars.
- Pack hot tomatoes, then add the hot cooking liquid to cover, leaving ½-inch headspace.
- Remove bubbles, wipe rims, cap as above.
Do not add oil, butter, meat, onion, peppers, or extra low-acid vegetables to this recipe. Those change density and acidity and push the product out of the tested process.
Water-bath processing times
Place jars on the rack. Water must cover lids by at least 1 inch (2 inches is safer). Bring to a full rolling boil, then start the timer.
Whole or halved tomatoes packed in water (hot or raw pack):
| Elevation | Pints | Quarts |
|---|---|---|
| 0–1,000 ft | 40 minutes | 45 minutes |
| 1,001–3,000 ft | 45 minutes | 50 minutes |
| 3,001–6,000 ft | 50 minutes | 55 minutes |
| Above 6,000 ft | 55 minutes | 60 minutes |
Keep a steady boil the entire time. If the boil breaks, bring it back and restart the timer. Add boiling water if the level drops below the lids.
When time is up, turn off the heat, remove the canner lid, and leave the jars in the water for 5 minutes. That pause reduces siphoning. Then lift jars straight up onto a towel. Do not tilt them. Do not retighten rings.
Leave jars undisturbed 12–24 hours.
Check seals and store
A sealed lid is concave and does not flex. Remove rings, wash the jars, label with pack style and date, and store in a cool, dark place. Keep rings off in storage so a failed seal is obvious later.
Unsealed jars: refrigerate and use soon, freeze, or reprocess within 24 hours in a clean jar with a new lid and the full process time. After 24 hours, do not reprocess.
Quality is best within a year. A sealed, correctly processed jar stored well can last longer, but color and texture fade.
Before eating any home-canned tomato product, look at the jar. Discard (do not taste) anything with a bulging lid, leaking seal, spurting liquid, off odor, mold, or unusual fizz. When in doubt, throw it out.
Problems that look alarming but are usually quality issues
Liquid loss (siphoning). Common with raw pack, tight packing, leftover air bubbles, or pulling jars out of boiling water immediately. If the seal is sound and the food looks and smells normal, the jar is still usable. Cover exposed tomatoes with the remaining liquid after opening, or use that jar first.
Separation. Water or pale liquid at the top or bottom is normal in whole tomatoes. Shake the jar before opening.
Floating tomatoes. Raw pack and loose fill cause this. Safety is not affected if headspace, acid, and process time were correct.
Failed seals. Food on the rim is the usual cause with tomatoes. Wipe rims with vinegar if juice is sticky. Leave jars in the canner 5 minutes after processing. Check for nicked rims.
Forgot the lemon juice. If you catch it within 24 hours, open the jars, add the correct acid, and reprocess with new lids for the full time. After that window, refrigerate and use quickly, or freeze. Do not leave under-acidified tomatoes on the pantry shelf.
When a water bath is the wrong tool
Stay with the tested water-pack recipe above for plain whole tomatoes. Switch methods when the product changes:
- Crushed tomatoes or plain sauce: different times (usually 35 minutes for pints and 45 minutes for quarts of crushed tomatoes at 0–1,000 ft). Still acidify.
- Salsa, sauce with onions or peppers, or any mix with low-acid vegetables: use a tested salsa or sauce recipe. Do not invent ratios and water-bath them.
- Anything with meat, oil, or dairy: pressure can only, using a tested recipe. Oil in particular is not added to home-canned tomatoes.
Pressure canning is an approved alternative for the same water-packed whole tomatoes. Acid still goes in the jar. Times are shorter (often 10–15 minutes under pressure, depending on the table and gauge), which some people prefer for texture. The water-bath process is not “less safe” when the acid and time are correct; it is simply a different tested combination of heat and acidity.
How to use a jar later
Drain or keep the packing water depending on the dish. The liquid is thin, not sauce.
Whole canned tomatoes work in braises, soups, shakshuka, curry, chili, and quick skillet sauces. Crush them by hand in the pan. For pizza sauce or a thick marinara, simmer them down; they were packed in water, so they start wetter than commercial “whole peeled in juice.”
If you want a thicker product next season, can crushed tomatoes or sauce instead of water-packed wholes.
Frequently asked questions
Can I skip peeling? Tested NCHFP directions peel first. Skins can affect heat penetration and leave tough bits in the jar. If you want an untested shortcut, that is a quality and safety tradeoff you would be making on your own.
Can I use lime juice? Not as a 1:1 swap in this tomato process. Use bottled lemon juice, citric acid, or 5% vinegar in the amounts listed.
Can I water-bath in a steam canner? Only when the official process time at your elevation is 45 minutes or less, and only if you follow steam-canner instructions for venting and water level. Quarts at 0–1,000 feet sit right on that 45-minute line. When the time is longer, use a boiling-water canner.
Do yellow or heirloom tomatoes need more acid? Use the same measured acid. Variety is not a reason to skip it. Color does not guarantee pH.
Why do some charts say 85 minutes? That time is for whole tomatoes packed in juice or packed raw with no added liquid. Water-packed tomatoes are the 40/45-minute chart.
Is a sealed lid proof the food is safe? No. A lid can seal on an under-acidified or under-processed jar. Safety comes from the combination of acid, tested time, jar size, pack style, and altitude — not from the pop alone.