How to Can Tomatoes at Home (Easy & Safe!)

Canning tomatoes is one of the best ways to preserve their fresh flavor, extend their shelf life, and reduce food waste. 

Whether you grow your own tomatoes or buy them in bulk during peak season, canning allows you to enjoy their rich taste year-round. 

In this article, I will walk you through the entire process of canning tomatoes, from selecting the right varieties to sealing and storing jars correctly. 

Not only that, you'll also learn essential techniques, safety precautions, and expert tips to ensure your canned tomatoes are flavorful, long-lasting, and safe to eat.

For more basics on home canning, check out canning for beginners.

Two Main Canning Methods

When it comes to preserving tomatoes, you have two main options: water-bath canning and pressure canning. The right method depends on what you're canning and whether you're adding extra ingredients.

Water-Bath Canning

Water-bath canning is the most common method because tomatoes are naturally acidic. It involves submerging jars in boiling water for a set time to kill bacteria and create a vacuum seal.

However, to ensure safety, you must add bottled lemon juice, citric acid, or vinegar to maintain the proper acidity level. Without this step, harmful bacteria could grow, leading to spoilage.

Pressure Canning

Pressure canning uses high-temperature steam in a sealed environment, making it the safest choice for low-acid foods.

If you're adding onions, garlic, peppers, or other low-acid ingredients, you need a pressure canner to prevent bacteria growth.

This method reaches higher temperatures than boiling water alone, killing harmful bacteria like Clostridium botulinum, which can cause botulism.

Choosing the right method is key to keeping your canned tomatoes safe and delicious. If you’re only canning plain tomatoes with added acid, a water bath is fine.

But if you’re making sauce with extra ingredients, go with pressure canning.

The Importance of Acidity in Canning

Tomatoes naturally contain acid, but their levels can vary depending on the variety and ripeness.

Some modern tomato varieties have lower acidity, which means they must be acidified before canning to prevent bacterial growth.

Adding lemon juice, citric acid, or vinegar ensures that the tomatoes stay at a safe pH level, reducing the risk of spoilage.

This step is essential when using a water-bath canner, as it prevents the growth of Clostridium botulinum, the bacteria responsible for botulism.

Must-Have Tools for Canning Tomatoes

Before you start canning, you’ll need the right tools to make the process easier, safer, and more efficient. Here’s what to have on hand:

Canning Jars & Lids

Use glass mason jars with two-piece lids (a flat sealing lid and a screw-on ring). Always check for cracks or chips before filling—damaged jars won’t seal properly. And remember, you must use new lids every time to ensure a secure seal!

Large Stockpot or Canner

If you're water-bath canning, you'll need a deep stockpot with a rack at the bottom. If you're pressure canning, a pressure canner is required, especially when adding low-acid ingredients like garlic or onions.

Canning Funnel

A wide-mouth funnel makes it easier to fill jars without spilling. This keeps the rims clean, which is key for getting a proper seal.

Jar Lifter

Since you’ll be working with boiling water, a jar lifter helps you safely remove hot jars without burning yourself or disturbing the seals.

Non-Metallic Spatula

Before sealing your jars, you’ll need to release trapped air bubbles. A plastic or silicone spatula works best—metal utensils can scratch the jars or interfere with sealing.

Lid Magnet or Tongs

You’ll need a way to handle hot lids after scalding them. A lid magnet or tongs keep things sanitary and prevent burns.

Vinegar & Clean Towels

Before sealing, wipe the jar rims with a paper towel dipped in vinegar. This removes food residue that could prevent a proper seal.

Having everything organized and ready to go before you start will make the process smoother and help you avoid mistakes.

1. Choosing the Right Tomatoes for Canning

Not all tomatoes are the same when it comes to canning. The variety you choose affects the texture, flavor, and overall quality of your preserved tomatoes.

Some work best for sauces and purees, while others hold their shape better when canned whole or diced. Picking the right type makes the process easier and gives you a better final product.

Best Tomato Varieties for Canning

For the best results, go with plum or paste-style tomatoes like Roma, San Marzano, or Amish Paste.

These varieties have thicker flesh, fewer seeds, and lower water content, making them perfect for canning. They hold their shape well in jars and develop a richer flavor over time.

If you're canning whole or diced tomatoes, these firmer types will prevent mushiness.

But if you’re working with juicier varieties like Beefsteak or Better Boy, expect more liquid separation in the jars. These work better for tomato juice, soup, or thin sauces.

Matching Tomatoes to Your Recipe

• Whole or diced tomatoes: Use firm plum or Roma tomatoes to keep a good texture.
• Tomato sauce & puree: Choose San Marzano or Amish Paste for a thick, rich consistency.
• Salsa: A mix of paste tomatoes and juicier varieties gives the best balance of texture and moisture.
• Tomato juice: Go for high-water-content tomatoes like Beefsteak.
• Ketchup & paste: Stick with paste tomatoes for a smooth, concentrated flavor.

Use Ripe, Firm Tomatoes

Always pick fully ripe, firm tomatoes for canning. Overripe ones can lead to spoilage, while underripe ones may not have the best flavor. Look for tomatoes with vibrant color and no soft spots.

The better the quality of your tomatoes, the better your canned goods will taste!

2. Preparing and Organizing Your Canning Area

Before you start canning, set up your workspace so everything runs smoothly. A little prep work will save you time and prevent mistakes.

Sanitize Your Jars, Lids, and Tools

Cleanliness is important when canning.

Start by washing your jars, lids, and tools in hot, soapy water, then rinse thoroughly. Jars should be kept warm in a pot of hot water or in the oven at low heat to prevent cracking when filled with hot tomatoes.

Lids should be scalded in hot water (but not boiled) to soften the sealing compound. Avoid touching the inside of the lids to keep them sterile.

3. Preparing Tomatoes for Canning

Taking the time to prepare your tomatoes correctly ensures better flavor, texture, and safety. This step includes cleaning, peeling, and cutting your tomatoes so they're ready to go into jars.

Blanching and Peeling Tomatoes the Right Way

Removing tomato skins is a must—they become tough after canning. The easiest way to peel them is by blanching:

1. Fill a large pot with water and bring it to a rolling boil.
2. Cut a small X at the bottom of each tomato—this helps loosen the skin.
3. Drop the tomatoes into the boiling water for 30 to 60 seconds until the skins start splitting.
4. Immediately transfer them to a bowl of ice water to stop the cooking process.
5. Once cooled, slide off the skins with your fingers—they should come off easily.

This method keeps your tomatoes firm and fresh while making peeling effortless. Just don’t over-boil them, or they’ll become too soft to handle.

Cutting and Prepping Tomatoes for Different Uses

Once peeled, you can prepare them based on how you plan to can them:

• Whole or Halved Tomatoes: Remove the core with a paring knife. If the core is deep, carve around it to avoid tough pieces in your jars.
• Diced Tomatoes: Cut into uniform pieces for even cooking and packing.
• Tomato Sauce or Puree: Blend or crush the peeled tomatoes, then cook them down to your preferred thickness.
• Juice or Stewed Tomatoes: Simmer peeled tomatoes for a few hours to deepen the flavor before canning.

Save That Tomato Juice!

Instead of discarding the juice that collects at the bottom of your bowl, pour it into your jars along with the tomatoes. This adds extra flavor and reduces waste.

By preparing your tomatoes properly, you’ll get better quality, better taste, and a smoother canning process. while making peeling effortless. Avoid over-boiling, as it can soften the tomatoes too much, making them difficult to handle.

Why Proper Preparation Matters

Taking the time to prepare your tomatoes correctly ensures a smooth canning process and better-quality results.

Blanching makes peeling effortless, removing the stems prevents tough pieces in your jars, and saving the natural juices enhances the overall flavor.

Proper preparation lays the foundation for successful canning, helping you achieve vibrant, flavorful, and well-preserved tomatoes.

4. Packing the Jars Properly

How you pack your jars affects the texture, shelf life, and overall quality of your canned tomatoes.

If done incorrectly, you might end up with floating tomatoes, trapped air bubbles, or jars that don’t seal properly. But don’t worry—following these simple steps will help you get it right.

Filling Jars for the Best Results

Start by making sure your jars are warm to prevent cracking when you add hot ingredients.

Using a canning funnel, carefully ladle the prepared tomatoes into each jar. Whether you're canning whole, diced, or crushed tomatoes, it's important to pack them tightly.

Tomatoes naturally float once processed, so reducing empty space helps keep them submerged.

If you’re using whole or halved tomatoes, press them down gently as you fill the jar to remove gaps. For diced or crushed tomatoes, spoon them in gradually, making sure they settle evenly.

Use Tomato Juice Instead of Water

Instead of adding water, use the natural tomato juice from your prep bowl to fill the remaining space in each jar. This boosts flavor and prevents unnecessary dilution.

Leave the Right Amount of Headspace

Headspace—the space between the food and the lid—is crucial for a proper seal. For tomatoes, leave ½ inch of headspace. This allows for expansion during processing.

If you overfill the jars, the contents may overflow and prevent sealing. If you underfill them, there may be too much air, increasing the risk of spoilage.

Debubble the Jars

Air bubbles can interfere with sealing, so before closing the jars, run a non-metallic spatula or plastic knife along the inside to release trapped air. Press gently on the tomatoes to help remove pockets of air.

If the liquid level drops after debubbling, add a little more tomato juice to maintain the ½ inch headspace.

Wipe the Rims for a Clean Finish

Before sealing, wipe the rims of the jars with a clean towel dipped in vinegar. This removes any residue that could prevent a tight seal. Even small food particles can cause sealing failures, so don’t skip this step!

Secure the Lids Without Over-Tightening

Place the scalded lids on top of the jars, then screw on the bands fingertip-tight. This means snug but not too tight. If you over-tighten, air won’t escape during processing, which can lead to improper sealing.

By packing your jars correctly, you're ensuring your tomatoes stay fresh, flavorful, and safe for long-term storage.

5. Sealing and Processing the Jars

Once your jars are packed and sealed, it’s time for processing. This step is critical because it kills harmful bacteria and creates a vacuum seal that keeps your tomatoes safe for months—or even years.

Processing Jars in a Water-Bath Canner

If you’re using the water-bath method, follow these steps:

1. Fill a large canner or deep stockpot with enough hot water to fully cover the jars by at least one inch.
2. Place a rack at the bottom to prevent the jars from sitting directly on the heat source.
3. Bring the water to a gentle boil, then carefully lower the jars into the canner using a jar lifter.
4. Once all jars are inside, cover the pot with a lid and maintain a steady boil for the required time:
   • Pints: 35 minutes
   • Quarts: 45 minutes
     (Adjust for altitude if needed.)
5. After processing, turn off the heat and let the jars sit in the hot water for a few minutes before removing them. This prevents sudden temperature changes that could cause breakage.

Processing Jars in a Pressure Canner

If you’re canning tomatoes with added ingredients like garlic or peppers, use a pressure canner instead:

1. Add 2–3 inches of water to the pressure canner and place the jars inside on the rack.
2. Secure the canner lid and heat on medium-high until steam starts venting.
3. Allow the steam to vent for 10 minutes, then place the weight on the vent pipe and bring the pressure up to:
   • 10–11 PSI for most elevations. (Check your manual for altitude adjustments.)
4. Process for the recommended time:
   • Pints: 20 minutes
   • Quarts: 25 minutes
5. When done, turn off the heat and let the pressure drop naturally before opening the canner. Removing jars too soon can cause liquid loss and affect the seal.

6. Cooling, Checking Seals, and Storing the Jars

Now that your jars are processed, the final steps are just as important as the canning itself.

Proper cooling, checking for airtight seals, and storing them correctly will ensure your tomatoes stay fresh and safe for months or even years.

Rushing through this step can lead to failed seals or spoilage, undoing all your hard work.

Let the Jars Cool Undisturbed

After removing the jars from the canner, place them upright on a clean towel or heat-resistant surface. Make sure they are spaced apart to allow proper airflow.

It’s important to let them cool for 12 to 24 hours without moving or tilting them. Shifting them too soon can break the seal, and placing hot jars directly on a cold surface can cause the glass to crack.

As the jars cool, listen for a satisfying “pop.” This means the lids are sealing properly, creating the vacuum needed for long-term storage.

Check for a Proper Seal

Once the jars have completely cooled, test the seal by pressing down on the center of each lid. If the lid stays firm and doesn’t pop back, the seal is secure.

Another way to check is by gently lifting the jar by the lid—if it holds, it’s sealed.

If a lid flexes or comes off easily, the jar did not seal properly. In that case, you can reprocess it within 24 hours using a new lid or store it in the fridge and use it within a few days.

Clean and Prepare for Storage

Before storing your jars, wipe them down with a damp cloth to remove any residue, especially around the rims and threads where tomato juices may have seeped out.

At this stage, it’s best to remove the screw bands before storage. While the lids must stay sealed, the bands can trap moisture, causing rust or hiding seal failures.

Label Your Jars

For easy tracking, write the canning date on each jar so you know when they were made. This helps you keep your stock organized and ensures you use them in the right order.

By taking the time to properly cool, check, and clean your jars, you’re ensuring that your tomatoes stay safe, flavorful, and ready to use whenever you need them!

7. Storing Canned Tomatoes for Long-Term Use

Proper storage is key to maintaining quality, flavor, and safety. Even if your canning process was perfect, poor storage conditions can lead to spoilage, weakened seals, or loss of taste.

Choose the Right Storage Location

Store your jars in a cool, dark, and dry place where the temperature stays between 50-70°F (10-21°C). A pantry, basement, or cupboard works well, as long as it’s away from heat sources like ovens or stoves. Avoid areas with high humidity since excess moisture can cause rust on lids, which may weaken the seal over time.

Know How Long Your Canned Tomatoes Last

Home-canned tomatoes maintain their best quality for 12 to 18 months, but as long as the seal remains intact, they can still be safe to eat beyond that. However, always check for signs of spoilage before using them.

If you notice a bulging lid, leaking contents, or an off smell when opening the jar, discard it immediately. If the tomatoes look discolored or have mold, do not take any risks—just throw them out.

Rotate Your Stock for Freshness

To keep your supply fresh, follow the first in, first out method. Use older jars first and place newly canned ones behind them. Labeling your jars with the canning date makes it easier to track which ones to use next.

By storing your canned tomatoes correctly and checking for spoilage before use, you can enjoy rich, flavorful tomatoes year-round, ready for your favorite soups, sauces, and homemade meals!ecks, you can extend the shelf life of your canned tomatoes and keep them in excellent condition for future meals.

Common Mistakes to Avoid When Canning Tomatoes

Even if you follow all the right steps, small mistakes can cause your tomatoes to spoil, your jars to lose their seal, or even make your canned goods unsafe to eat. Avoiding these common errors will help ensure your tomatoes stay fresh, flavorful, and safe for long-term storage.

Overfilling or Underfilling Jars

Getting the right headspace—the space between the food and the lid—is key to a proper seal. You should leave ½ inch of headspace in each jar.

If you overfill, the expanding tomatoes may overflow during processing, preventing the lid from sealing. If you underfill, too much oxygen remains in the jar, which increases the risk of spoilage.

Skipping the Debubbling Step

Air bubbles trapped inside the jar can prevent a proper vacuum seal and may lead to bacterial growth. Before sealing your jars, use a non-metallic spatula or plastic knife to release any air pockets by running it along the inside edges of the jar. If the liquid level drops after removing bubbles, top it off with a little more tomato juice to maintain the correct headspace.

Not Wiping the Jar Rims

Even a small amount of tomato residue on the jar rim can prevent the lid from sealing properly. Before placing the lid on, always wipe the rim with a clean cloth dipped in vinegar. This ensures a clean surface and helps prevent contamination.

Tightening the Lids Too Much

It may seem like tightening the lids as much as possible would help seal the jar, but this can actually prevent air from escaping during processing, leading to seal failure. Instead, screw the bands on fingertip-tight—firm but not overly tight.

Using the Wrong Canning Method

Not all tomato products can be processed the same way. If you're canning plain tomatoes with added acid, a water-bath canner is safe. However, if you’re adding low-acid ingredients like garlic, onions, or peppers, you must use a pressure canner to prevent bacterial growth. Using the wrong method can lead to unsafe food.

Ignoring Altitude Adjustments

If you live at a high elevation, processing times and pressure levels need to be adjusted. At higher altitudes, boiling water reaches a lower temperature, which means food requires a longer processing time to be safe. Check an altitude-adjusted canning chart to make sure your tomatoes are properly processed.

Storing Jars Incorrectly

Once your jars are sealed, they need to be stored in the right conditions to stay fresh. Exposure to heat, sunlight, or humidity can weaken the seals and shorten the shelf life. It’s also important to remove the screw bands before storing. This helps prevent moisture from getting trapped and causing rust or hidden seal failures.

By avoiding these common mistakes, you’ll have perfectly sealed, safe, and flavorful canned tomatoes that you can enjoy for months to come!

Enjoy Fresh Tomatoes All Year

Canning tomatoes is a simple yet rewarding way to preserve their rich flavor and nutritional value for long-term use.

By following the right methods, you can enjoy homemade tomato products year-round without relying on store-bought alternatives.

Whether you're making whole canned tomatoes, sauces, or salsas, the process ensures that you always have a supply of fresh, high-quality ingredients at your fingertips.

By incorporating these best practices into your canning routine, you can confidently store flavorful tomatoes that are ready to enhance your favorite recipes at any time.

With the right approach, canning becomes an essential skill that helps reduce waste, save money, and provide a dependable pantry staple for your home kitchen.

Frequently Asked Questions (FAQs)

If you still have questions, you're not alone! Here are answers to some of the most common concerns people have about canning tomatoes.

Do I need to add lemon juice when canning tomatoes?

Yes, you do! Even though tomatoes are naturally acidic, their acidity levels can vary depending on the variety and ripeness. To keep your canned tomatoes safe, always add bottled lemon juice, citric acid, or vinegar to each jar.

For pints, add 1 tablespoon of bottled lemon juice or ¼ teaspoon of citric acid. For quarts, double those amounts. If you prefer using vinegar, use 2 tablespoons per pint or 4 tablespoons per quart, but keep in mind that vinegar may slightly change the flavor.

If you're pressure canning, adding acid isn't required, but it helps maintain color and flavor, so it's still a good idea.

How long do canned tomatoes last?

If stored in a cool, dark, and dry place, home-canned tomatoes maintain their best quality for 12 to 18 months. However, as long as the seal remains intact and there are no signs of spoilage, they can be safe to eat for much longer.

Before using a jar, always check for bulging lids, leaks, unusual smells, or discoloration. If anything seems off, it’s better to throw it out than risk eating spoiled food.

Can I reuse canning lids?

No, you should always use new lids when canning. The sealing compound on the lid is designed for one-time use only. Reusing lids increases the risk of seal failure, which could lead to spoilage or unsafe food.

The good news is that glass jars and screw bands can be reused as long as they are in good condition. Just make sure to inspect them for cracks or rust before canning.

Why did my tomatoes float in the jar after canning?

Floating tomatoes happen when there’s too much liquid in the jar or the tomatoes weren’t packed tightly enough. This is common with juicier tomato varieties that naturally release more water during processing.

To minimize floating, pack the tomatoes firmly into the jar and use their natural juice instead of added water. You can also remove air bubbles before sealing to help keep everything settled. Even if your tomatoes float, they are still safe to eat as long as the jar is properly sealed.

Can I add garlic, onions, or other seasonings to my canned tomatoes?

It depends on the method you're using. If you're water-bath canning, you should only add tomatoes, salt, and acid (like lemon juice or citric acid). Adding low-acid ingredients like garlic, onions, or peppers lowers the overall acidity, which increases the risk of botulism.

However, if you're using a pressure canner, you can safely add these ingredients because the higher temperatures will kill harmful bacteria. If you want extra flavor but don't have a pressure canner, it's best to add seasonings when cooking instead of during canning.