Last Updated on October 22, 2026 by D. Ruddy
Preserving your garden’s tomato harvest through pressure canning tomatoes ensures shelf-stable, flavorful results you can enjoy year-round. This method is the only USDA-approved way to safely can tomatoes without added acid, preventing botulism while locking in freshness. Below, you’ll find everything you need to master the process, from prep to storage.
Pressure canning is the safest method for canning tomatoes without added acid because it reaches 240°F, the temperature needed to destroy botulism spores. A weighted or dial gauge canner works best for consistent results.
Why Pressure Canning Is Essential for Tomatoes
Tomatoes fall into a unique category for canning. While they’re acidic, some modern varieties have a pH above 4.6, the threshold for safe water bath canning. This variability means pressure canning tomatoes is the only 100% reliable method to eliminate botulism risks.
Pressure canners create an environment where temperatures exceed boiling, reaching 240°F at 10-11 psi (depending on altitude). This kills harmful bacteria, yeasts, and molds that could otherwise spoil your canned goods.
Additionally, pressure canning preserves more nutrients than other methods. According to the National Center for Home Food Preservation, properly canned tomatoes retain most of their vitamin C and lycopene content for up to a year.
- Safety: Eliminates botulism risk in low-acid environments
- Shelf Life: Canned tomatoes last 12-18 months without refrigeration
- Nutrient Retention: Maintains vitamins and antioxidants better than other preservation methods
- Versatility: Use for sauces, soups, stews, and salsas
- Cost-Effective: Preserve large harvests without freezer space
| Canning Method |
Safety for Tomatoes |
Temperature Reached |
| Water Bath |
Only with added acid (lemon juice/vinegar) |
212°F |
| Pressure Canning |
Yes, for all tomato varieties |
240°F |
As shown, pressure canning is the only method that guarantees safety for all tomato types without modifications.
Equipment You Need for Pressure Canning Tomatoes
Before you begin, gather all necessary equipment. Skipping any item can compromise safety or quality. A pressure canner is non-negotiable—never attempt to can tomatoes in an Instant Pot or other electric pressure cooker unless it’s specifically rated for canning.
Here’s what you’ll need for a successful batch:
- Pressure Canner: Choose between weighted gauge (easier for beginners) or dial gauge (more precise) models. Brands like Presto and All-American are trusted by home canners.
- Canning Jars: Use standard mason jars (pint or quart size) with new lids and rings. Check for nicks or cracks that could prevent proper sealing.
- Jar Lifter: Essential for safely moving hot jars in and out of the canner.
- Canning Funnel: Helps fill jars neatly without spills on the rims.
- Bubble Remover: A plastic or silicone tool to release air bubbles before sealing.
- Lid Magnet: Makes handling hot lids easier.
- Clean Towels: For wiping jar rims and handling hot equipment.
Tip: Inspect your pressure canner’s gasket and safety valve before each use. Replace if worn or damaged to ensure proper pressure regulation.
| Equipment |
Purpose |
Estimated Cost |
| Pressure Canner |
Creates high-temperature environment |
$80-$200 |
| Canning Jars (12-count) |
Storage containers |
$15-$30 |
| Basic Canning Kit |
Includes funnel, lifter, bubble remover |
$10-$20 |
Investing in quality equipment pays off in safety and longevity. A good pressure canner can last decades with proper care.
Preparing Tomatoes for Pressure Canning
Proper preparation is key to achieving the best texture and flavor in your canned tomatoes. Start with high-quality, ripe tomatoes—Roma and San Marzano varieties are popular for canning due to their meaty texture and low water content.
Follow these steps to prepare your tomatoes:
- Wash and Sort: Rinse tomatoes under cool water to remove dirt. Discard any with bruises, soft spots, or signs of spoilage.
- Peel (Optional): For smooth sauces, blanch tomatoes in boiling water for 30-60 seconds, then plunge into ice water. The skins will slip off easily. For whole or diced tomatoes, peeling is optional.
- Remove Cores: Use a paring knife or corer to remove the stem end and any tough core.
- Chop or Leave Whole: For crushed tomatoes, quarter them. For whole tomatoes, pack as-is. For diced, cut into uniform pieces.
- Pre-Cook (Hot Pack): Simmer tomatoes in a pot for 5-10 minutes to soften and remove excess liquid. This helps maintain color and texture.
- Add Acid (Optional): While not required for pressure canning, adding 1 tbsp of lemon juice per pint or 2 tbsp per quart can enhance acidity and flavor.
- Pack Jars: Fill jars with prepared tomatoes, leaving 1-inch headspace for quarts and ½-inch for pints.
Warning: Never add thickeners like flour or cornstarch to tomatoes before canning. These can prevent proper heat penetration and lead to unsafe canning conditions.
For the best results, work with tomatoes at their peak ripeness. Underripe tomatoes can be more acidic, while overripe ones may turn mushy during processing. According to the USDA, about 21 pounds of fresh tomatoes yield approximately 7 quarts of canned tomatoes.
Step by Step Pressure Canning Process
Follow these steps carefully for safe pressure canning tomatoes. Even small deviations can affect safety and quality.
Step 1: Prepare Your Canner and Jars
Before loading your canner, ensure it’s in good working condition. Fill the canner with 2-3 inches of hot water (follow your manufacturer’s guidelines). Place the rack inside to keep jars off the bottom.
Preheat the water to 140°F for raw-packed tomatoes or 180°F for hot-packed.
Wash your jars and lids in hot, soapy water. Keep jars hot until filling to prevent thermal shock when they enter the canner.
Step 2: Fill the Jars
Using your canning funnel, fill jars with prepared tomatoes. For raw pack, simply pack tomatoes into jars without pre-cooking. For hot pack (recommended for better quality), fill jars with hot tomatoes and cooking liquid.
Leave the proper headspace:
- Pints: ½-inch headspace
- Quarts: 1-inch headspace
Step 3: Remove Air Bubbles
Run your bubble remover tool around the inside of each jar to release trapped air. This ensures proper heat circulation during processing. Wipe the jar rims with a clean, damp cloth to remove any residue that could prevent a good seal.
Step 4: Apply Lids and Rings
Place a lid on each jar, ensuring the sealing compound makes full contact with the rim. Screw on the ring just until it’s fingertip-tight—don’t overtighten, as this can prevent proper venting during processing.
Step 5: Load the Canner
Using your jar lifter, place jars on the rack in the canner. Ensure jars don’t touch each other or the canner walls. If stacking layers, place a second rack between them.
Step 6: Process According to Your Altitude
Processing times depend on your altitude and jar size. Always follow USDA guidelines or your canner’s manufacturer instructions. Here’s a general reference:
| Jar Size |
0-1,000 ft |
1,001-3,000 ft |
3,001-6,000 ft |
6,001+ ft |
| Pints |
10 lbs |
11 lbs |
12 lbs |
13 lbs |
| Quarts |
10 lbs |
11 lbs |
12 lbs |
13 lbs |
| Jar Size |
Processing Time (Hot Pack) |
Processing Time (Raw Pack) |
| Pints |
20 minutes |
25 minutes |
| Quarts |
25 minutes |
30 minutes |
Adjust processing time based on your specific altitude. When in doubt, consult the USDA Complete Guide to Home Canning or your local extension office.
Step 7: Vent the Canner
Place the lid on the canner and lock it according to the manufacturer’s instructions. Turn heat to high. Once steam begins escaping from the vent pipe, let it vent for 10 minutes.
This step is crucial to ensure all air is removed from the canner before pressurizing.
Step 8: Pressurize and Process
After venting, place the weight on the vent pipe or close the petcock (for dial gauge canners). Reduce heat to maintain the proper pressure for your altitude. Start timing only once the canner reaches the correct pressure.
Maintain steady pressure throughout processing. If pressure drops below the required level, bring it back up and restart the timer.
Step 9: Cool Down and Remove Jars
When processing time is complete, turn off the heat and let the canner cool naturally. Do not attempt to cool it quickly with cold water—this can cause jars to break and is unsafe.
Once pressure returns to zero (for weighted gauge) or the dial reads zero (for dial gauge), wait an additional 10 minutes before opening the canner. Remove the weight or open the petcock, then open the lid away from you to avoid steam burns.
Using your jar lifter, remove jars and place them on a towel-lined countertop. Do not tighten rings or check seals yet.
Step 10: Check Seals and Store
After 12-24 hours, check the seals. A properly sealed jar will have a concave lid that doesn’t pop when pressed. Remove the rings, wash the jars, label them with contents and date, and store in a cool, dark place.
If any jars didn’t seal, refrigerate and use within a week, or reprocess with a new lid within 24 hours.
Important: Never leave jars in the canner after processing is complete. The residual heat can overcook the contents and weaken seals.
Common Mistakes to Avoid When Pressure Canning Tomatoes
Even experienced canners sometimes make errors that can affect safety or quality. Being aware of these common pitfalls can help you avoid them and ensure successful pressure canning tomatoes every time.
- Overfilling Jars: Leaving insufficient headspace can cause siphoning (liquid escaping during processing) and poor seals. Always measure headspace with a ruler for accuracy.
- Using Damaged Jars or Lids: Cracks, chips, or rust on jars can prevent proper sealing. Inspect all equipment before each use.
- Skipping the Venting Step: Failing to vent the canner properly can result in uneven heat distribution and underprocessed food.
- Adjusting Pressure Incorrectly: Using the wrong pressure for your altitude can lead to underprocessing. Always check your altitude and adjust accordingly.
- Cooling the Canner Too Quickly: Adding cold water or trying to rush the cooling process can cause jars to break and may result in unsafe canning conditions.
- Ignoring Altitude Adjustments: If you’ve moved or are canning at a different elevation than usual, recalculate your processing pressure and time.
- Reusing Lids: Canning lids are designed for single use. The sealing compound wears out after one use, increasing the risk of failure.
| Mistake |
Risk |
Solution |
| Overfilling jars |
Siphoning, poor seals |
Always leave proper headspace |
| Skipping venting |
Uneven heat distribution |
Vent for full 10 minutes |
| Using old lids |
Seal failure |
Use new lids each time |
According to a study by the University of Georgia, improper canning procedures are responsible for most cases of home-canned foodborne illness. Taking the time to follow proper procedures ensures your canned tomatoes are both delicious and safe.
Altitude Adjustments for Pressure Canning Tomatoes
Altitude significantly affects pressure canning because water boils at lower temperatures as elevation increases. This means you must adjust your canner’s pressure to compensate for the lower boiling point of water at higher altitudes.
Here’s how to determine your altitude and make the necessary adjustments:
- Find Your Altitude: Use an online altitude finder, check a topographic map, or contact your local extension office. Many smartphone apps can also provide this information.
- Determine Your Canner Type: Weighted gauge canners have preset pressure settings (usually 10 or 15 psi), while dial gauge canners allow for precise pressure adjustments.
- Adjust Pressure Accordingly: For weighted gauge canners, use the higher weight setting at altitudes above 1,000 feet. For dial gauge canners, increase the pressure as needed for your altitude range.
- Check Manufacturer Guidelines: Always consult your canner’s manual for specific altitude adjustments, as these can vary slightly between models.
| Altitude (Feet) |
Weighted Gauge (psi) |
Dial Gauge (psi) |
| 0-1,000 |
10 |
10 |
| 1,001-3,000 |
15 |
11 |
| 3,001-6,000 |
15 |
12 |
| 6,001-8,000 |
15 |
13 |
| 8,001+ |
15 |
14 |
Remember that these are general guidelines. Always verify with your specific canner’s manual or the USDA guidelines for the most accurate information.
Tip: If you live in a high-altitude area, consider getting your dial gauge canner tested annually at your local extension office to ensure accuracy.
Storing and Using Your Canned Tomatoes
Proper storage is essential to maintain the quality and safety of your canned tomatoes. Even with perfect canning techniques, improper storage can lead to spoilage or reduced shelf life.
Storage Guidelines
Follow these best practices for storing your canned tomatoes:
- Cool, Dark Place: Store jars in a pantry, cellar, or cupboard away from direct light and heat sources. Ideal temperature is 50-70°F.
- Upright Position: Store jars upright to prevent the lids from coming into contact with the contents, which could corrode the seal.
- Remove Rings: After 24 hours, remove the screw bands to prevent rust and to make it easier to detect seal failures.
- Label Clearly: Use waterproof labels to note the contents and canning date. This helps with rotation and usage planning.
- Avoid Freezing Temperatures: While canned tomatoes won’t freeze solid in a typical freezer, temperatures below 32°F can cause liquid expansion and potential jar breakage.
Shelf Life
Properly canned and stored tomatoes have an impressive shelf life. Here’s what to expect:
- Best Quality: 12-18 months
- Safe to Eat: Up to 2-3 years (though quality may decline after 18 months)
- After Opening: 5-7 days in the refrigerator
According to the USDA, home-canned foods retain their best quality for about a year, but remain safe indefinitely if the seal remains intact and the jar shows no signs of spoilage.
Using Canned Tomatoes in Recipes
Your home-canned tomatoes are incredibly versatile in the kitchen. Here are some delicious ways to use them:
- Pasta Sauces: Use as a base for marinara, Alfredo, or meat sauces. The concentrated flavor works perfectly.
- Soups and Stews: Add to chili, vegetable soup, or beef stew for rich, tomatoey depth.
- Salsas: Blend with onions, peppers, and spices for fresh-tasting salsa year-round.
- Casseroles: Incorporate into lasagna, eggplant Parmesan, or other baked dishes.
- Braising Liquids: Use as a base for braising meats like chicken, pork, or beef.
- Drinks: Blend into Bloody Mary mix or gazpacho for a refreshing summer beverage.
Important: If you notice any signs of spoilage—bulging lids, off odors, mold, or liquid seeping from the jar—discard the contents immediately. Do not taste-test suspicious cans.
Troubleshooting Common Issues with Canned Tomatoes
Even with careful processing, you might encounter some issues with your canned tomatoes. Here’s how to identify and address common problems:
| Issue |
Cause |
Solution |
| Jars didn’t seal |
Lid defect, rim not clean, insufficient headspace |
Reprocess within 24 hours with new lid |
| Liquid loss (siphoning) |
Temperature changes, overfilling |
Leave proper headspace, cool jars gradually |
| Cloudy liquid |
Starch from tomatoes, hard water |
Harmless; stir before using |
| Floating tomatoes |
Air trapped in tomatoes |
Hot pack tomatoes to remove air |
| Mold growth |
Improper sealing or storage |
Discard immediately |
Most issues with canned tomatoes are preventable with proper technique. The National Center for Home Food Preservation reports that 90% of canning failures are due to procedural errors rather than equipment problems.
Frequently Asked Questions
Can I pressure can tomatoes without peeling them?
Yes, you can pressure can tomatoes without peeling them. The skins will soften during processing and are perfectly safe to eat. However, peeling is recommended if you prefer a smoother texture for sauces or soups.
The skin can sometimes separate during canning, but it doesn’t affect safety or flavor.
Do I need to add lemon juice when pressure canning tomatoes?
No, you don’t need to add lemon juice when pressure canning tomatoes because the pressure canning process itself ensures safety. However, adding 1 tbsp of lemon juice per pint or 2 tbsp per quart can help maintain acidity and enhance flavor, especially for less acidic tomato varieties.
How do I know if my pressure canner is working properly?
Check that your canner maintains steady pressure during processing. For weighted gauge canners, the weight should rock gently or jiggle consistently. For dial gauge canners, the needle should stay in the correct pressure range.
Also, inspect the gasket and safety valve before each use. Many extension offices offer free canner gauge testing for dial gauge canners.
Can I use an Instant Pot for pressure canning tomatoes?
No, most Instant Pot models are not approved for home canning by the USDA. Pressure canning requires specific temperatures and pressures that most electric multi-cookers cannot reliably maintain. Only use a dedicated pressure canner that meets USDA guidelines for safe canning.
What’s the difference between hot pack and raw pack for tomatoes?
Hot pack involves pre-cooking the tomatoes before packing them into jars, which helps remove air, concentrates flavors, and results in a higher quality product with less floating. Raw pack means packing uncooked tomatoes into jars, which is faster but may result in more liquid loss during processing and potentially less consistent texture.
Final Thoughts
Pressure canning tomatoes is a rewarding way to preserve your harvest safely and deliciously. By following proper procedures, using the right equipment, and understanding altitude adjustments, you can enjoy home-canned tomatoes in your favorite recipes year-round. Remember that safety comes first—never cut corners on processing times or pressure requirements.
With practice, you’ll develop confidence in your canning skills and the satisfaction of stocking your pantry with high-quality, home-preserved goods.
