Pressure canning tomatoes is a tested alternative to a long boiling-water bath, not a way to skip acid. For plain whole, crushed, juiced, or sauced tomatoes, USDA processes treat the two methods as equivalent heat treatments. The pressure option is shorter because the temperature is higher. It is not the same long, high-heat process used for meat or low-acid vegetables.
That distinction matters. Many modern tomatoes sit near pH 4.6, the line where Clostridium botulinum can grow in a sealed jar. Adding bottled lemon juice, citric acid, or 5% vinegar is required for these products whether the jars go into a pressure canner or a water bath.
Why Pressure Canning Tomatoes Is Often the Better Choice
A boiling-water bath for raw-packed whole tomatoes can take 85 minutes or more, plus extra time at higher elevations. The matching pressure process is often 10 to 25 minutes once the canner is at the correct pressure. Extension specialists note that the shorter heat exposure can produce a higher-quality, more nutritious jar.
Pressure canning is also the only safe option once low-acid ingredients enter the recipe: onions, peppers, celery, mushrooms, okra, zucchini, or meat. Those mixtures are not interchangeable with a water-bath tomato recipe.
Use pressure canning when:
- You want a shorter process for plain tomatoes
- You are packing dense products such as crushed tomatoes or sauce
- The recipe includes vegetables or meat
- A tested recipe lists only a pressure process
A water bath is still acceptable for acidified whole, crushed, juiced tomatoes and some high-acid salsas, if you follow a current tested recipe and adjust time for altitude.
The Rule Most People Get Wrong: Acid Still Goes in the Jar
Pressure does not replace acid in USDA tomato processes that offer both methods. Those shorter pressure times were calculated for acidified tomatoes. They were not written as botulism-kill processes for unacidified fruit. If acid is omitted, there is no published home process that tells you how long to run the canner instead.
Add acid to each jar before filling, or immediately after filling, using one of these measured amounts:
| Acid | Per pint | Per quart |
|---|---|---|
| Bottled lemon juice (from concentrate) | 1 tablespoon | 2 tablespoons |
| Citric acid | 1/4 teaspoon | 1/2 teaspoon |
| Vinegar, 5% acidity | 2 tablespoons | 4 tablespoons |
Use bottled lemon juice, not fresh. Fresh juice varies in acidity. Vinegar is safe at the amounts above but can change flavor. A small amount of sugar may be added to soften the taste; it does not replace acid. Do not use ascorbic acid (vitamin C) as a substitute. It is a color aid, not an acidifier.
Salt is optional: about 1/2 teaspoon per pint or 1 teaspoon per quart. It is for flavor only.
Choose the Right Tomato Product Before You Heat the Canner
Processing time depends on how the tomatoes are packed, not on the variety name on the seed packet.
Crushed tomatoes, no added liquid. The most useful everyday pack. Quarter peeled tomatoes, heat and crush in batches, simmer 5 minutes, and fill hot. Good for soups, chili, and sauces you will finish later.
Whole or halved, packed in water. Fastest pressure process. Flavor is slightly more diluted.
Whole or halved, packed in tomato juice. Stronger tomato flavor than a water pack. Longer process than water pack.
Whole or halved, raw, no added liquid. Tomatoes are pressed into the jar until their own juice fills the spaces. Convenient, but the process is longer and siphoning is more common.
Tomato juice or standard tomato sauce. Both are hot-packed. Sauce should be a tested “standard” sauce, not an untested kitchen mix of extra vegetables.
Mixtures that must be pressure canned. Tomatoes with okra or zucchini, Mexican tomato sauce, spaghetti sauce without meat, and spaghetti sauce with meat each have their own times. Do not convert a water-bath salsa recipe into an untested pressure recipe, and do not add extra vegetables to a crushed-tomato process.
Ohio State notes that canning whole cherry or grape tomatoes is not advised.
What You Need
- A pressure canner, not a pressure cooker or electric multi-cooker. A canner must hold at least four quart jars and maintain a regulated pressure.
- Dial-gauge or weighted-gauge lid, in good working order. Have dial gauges checked yearly through a local Extension office when possible.
- Canning jars, new lids, and bands
- Jar lifter, bubble tool, and clean towels
- Bottled lemon juice or citric acid
- A pot for peeling and heating tomatoes
Inspect the gasket, vent pipe, and safety valve before each season. A blocked vent or a gauge that reads several pounds off can underprocess food or blow liquid out of jars.
Start With Tomatoes That Are Safe to Can
Use firm, ripe, disease-free tomatoes from healthy vines. Do not can fruit from frost-killed or dead vines; acidity and quality drop. Cut away bruises and decay. Overripe, soft fruit is a poor candidate for whole packs and a better candidate for sauce if the sound portions are still good.
Green tomatoes are more acidic than ripe ones and may be canned with the same acidification and processes.
Approximate yields from NCHFP: about 21 pounds of whole or halved tomatoes fill 7 quarts, or 13 pounds fill 9 pints. Crushed tomatoes take about 22 pounds for 7 quarts or 14 pounds for 9 pints.
Peel tomatoes for whole, halved, and crushed packs. Dip in boiling water 30 to 60 seconds until skins split, cool in cold water, slip skins, and core. Peeling improves quality and removes skin that can harbor soil organisms.
How to Pressure Can Tomatoes, Step by Step
- Wash jars in hot soapy water. Keep them hot. Prepare lids according to the manufacturer.
- Put 2 to 3 inches of hot water in the canner, unless the canner manual specifies more. Add the rack.
- Add acid to each empty jar, then optional salt.
- Pack using a tested style:
- Hot pack, crushed: Heat a sixth of the batch first, crushing to release juice. Keep the pot at a boil while adding remaining quarters. Simmer 5 minutes. Fill jars with hot crushed tomatoes, 1/2-inch headspace.
- Hot pack, whole/halved in water or juice: Cover peeled tomatoes with water or juice, boil 5 minutes, pack hot tomatoes and hot liquid, 1/2-inch headspace.
- Raw pack, water or juice: Fill jars with raw peeled tomatoes, cover with hot water or hot juice, 1/2-inch headspace.
- Raw pack, no added liquid: Pack raw peeled tomatoes, pressing until juice fills spaces, 1/2-inch headspace.
- Remove air bubbles, recheck headspace, wipe rims, apply lids, and tighten bands fingertip-tight.
- Load the canner, lock the lid, and heat on high with the vent open.
- Vent steam steadily for 10 minutes, then add the weight or close the petcock.
- Bring the canner to the pressure required for your gauge and altitude. Start timing only after that pressure is reached. Keep pressure steady. If it drops below the target, bring it back up and restart the timer.
- When time is up, turn off the heat. Let pressure fall to zero on its own. Wait 10 minutes more, then open the vent, remove the lid away from you, and let jars sit in the canner 5 to 10 minutes before lifting them out. Fast cooling is a common cause of siphoning.
- Cool jars 12 to 24 hours, check seals, remove bands, wash jars, label, and store in a cool, dark place. Unsealed jars may be refrigerated and used, or reprocessed within 24 hours with a new lid.
Pressure Times for Common Tomato Packs
These are the combinations most home canners use: 11 pounds on a dial gauge at 0–2,000 feet, or 10 pounds on a weighted gauge at 0–1,000 feet. Above those elevations, raise pressure rather than guessing at extra minutes. Weighted-gauge canners generally move to 15 pounds above 1,000 feet. Dial gauges increase about 1 pound per 2,000 feet. Always match the table in the recipe you are following.
| Product | Pack | Jar size | Time at 11 lb dial / 10 lb weighted |
|---|---|---|---|
| Crushed tomatoes, no added liquid | Hot | Pints or quarts | 15 minutes |
| Tomato juice or standard tomato sauce | Hot | Pints or quarts | 15 minutes |
| Whole or halved tomatoes packed in water | Hot or raw | Pints or quarts | 10 minutes |
| Whole or halved packed in juice, or raw with no added liquid | Hot or raw | Pints or quarts | 25 minutes |
| Tomatoes with okra or zucchini | Hot | Pints / quarts | 30 / 35 minutes |
| Spaghetti sauce without meat | Hot | Pints / quarts | 20 / 25 minutes |
| Spaghetti sauce with meat | Hot | Pints / quarts | 60 / 70 minutes |
NCHFP also publishes longer times at lower pressures, such as 40 minutes at 6 pounds dial / 5 pounds weighted for juice-packed or no-liquid whole tomatoes. Those options exist so canners that cannot hold a higher pressure still have a tested path. Do not invent a middle pressure of your own.
Headspace for most of these packs is 1/2 inch. Standard tomato sauce is often listed at 1/4 inch. Meat sauces use 1 inch. Follow the specific recipe.
What “Good” Jars Look Like After Processing
Separation into pulp and liquid is common, especially if tomatoes were crushed raw before heating. An enzyme in cut fruit breaks down pectin. Heating to about 180°F quickly after cutting limits that split. Separation is a quality issue, not a safety defect, if the jar was acidified, processed, and sealed. Stir before use.
Floating whole tomatoes are also common in raw packs. Firm fruit, a tight pack without crushing, bubble removal, and a hot pack reduce it.
Some liquid loss, or siphoning, happens often with tomatoes in a pressure canner. If the seal is sound and at least half the liquid remains, the food is still usable; use those jars first. If most of the liquid is gone, refrigerate and use within a few days. Causes include overfilling, loose or overly tight bands, pressure that bounced during the process, and cooling the canner too fast.
Discard jars with bulging lids, spurting liquid, off odors, visible mold, or unsealed lids discovered later in storage. Do not taste suspect food.
Mistakes That Undermine a Safe Batch
Skipping acid because “pressure canning kills everything.” For these tomato processes, it does not replace acid.
Adding extra vegetables to crushed tomatoes or juice. Onions, peppers, and celery change acidity and density. Use a tested mixed-vegetable or spaghetti-sauce recipe instead.
Canning in an Instant Pot or similar multi-cooker. These appliances are not approved as home pressure canners.
Using a pressure cooker that is too small or cannot hold a steady, documented pressure.
Ignoring altitude. At higher elevations, water boils at a lower temperature. Pressure must increase so the jar still reaches the intended heat.
Leaving skins on for a crushed or whole pack when the tested method calls for peeling.
Trusting a home pH meter after the fact. Extension guidance treats acidification plus a tested process as the control, not a spot-check with consumer meters after the jars have sat. If acid was forgotten, the safe window to reprocess is short; past that point the batch should not be saved as a shelf-stable product.
Reprocessing last year’s unsealed or questionable jars without starting from a tested method and new lids.
When a Water Bath Still Makes Sense
If you only can a few jars of acidified crushed tomatoes and do not own a pressure canner, a water bath remains a documented option. Expect a much longer boil: often 35–45 minutes for crushed pints and quarts at low elevation, and 85 minutes or more for some whole raw packs.
High-acid condiments such as ketchup and many tested salsas are usually water-bath products because vinegar or bottled citrus is built into the recipe at a known rate. Do not assume a favorite restaurant-style salsa is safe to can unless it matches a current tested formula.
Frequently Asked Questions
Do I peel tomatoes if I am pressure canning them? Yes for whole, halved, and crushed packs in USDA procedures. Peeling is part of the tested method.
Can I leave the seeds in? Yes. Seeds do not change the process. Strain them only if you want juice or a smoother sauce, and use the juice or sauce process that matches the finished texture.
Is citric acid better than lemon juice? Both are accepted. Citric acid adds less flavor. Measure it; a heaping spoonful is not the tested amount.
Can I pressure can tomatoes without added liquid so they are less watery? Yes. That pack exists, and the process is 25 minutes at 11/10 pounds for pints or quarts at low elevation, with acid added. Expect more siphoning than a hot crushed pack.
Can I can tomatoes with basil, garlic, or oil in the jar? Not as an add-in to a plain tomato process. Oil is a special concern because it can shield spores. Use tested recipes for seasoned sauces. Do not put oil on top of home-canned tomatoes.
How long do sealed jars keep? Best quality is usually within a year in a cool, dark place. Safety depends on a sound seal and a correct process, not on an arbitrary date printed on the lid.
What if my weighted gauge rocks hard the whole time? A gentle, regular rock or jiggle is the goal on most weighted-gauge models. A violent rock means pressure is too high, which cooks the tomatoes harder and pushes liquid out. Adjust the heat.
Pressure canning tomatoes is worth learning because it saves time and often protects texture better than an 85-minute water bath. Treat it as a tested shortcut, not a loophole. Add the acid, match the pack to the table, hold a steady pressure for your elevation, and cool the canner slowly. That is the difference between a pantry full of useful jars and a batch you cannot trust.