How to Safely Can Tomatoes: The Complete Guide

If you’re like me, then you love homegrown tomatoes. They are a delicious and versatile vegetable that can be easily preserved at home by either pressure canning or water bath canning. In this guide, we will walk through how to can tomatoes by covering safety concerns, altitude adjustments, equipment and supplies needed, and step-by-step instructions for both methods. Let’s get started!

Canning tomatoes at home is a great way to preserve their delicious flavor and nutritional value for later use. The two most common methods are pressure canning and water bath canning. Pressure canning is my recommended method for preserving tomatoes because it results in a higher quality product. However, water bath canning is still a safe option, especially if you are at a lower altitude.

Before getting started, it’s important to understand the safety concerns associated with canning tomatoes. Botulism is a deadly form of food poisoning that can be caused by improperly processed foods. It is rare but serious, so it is important to follow all instructions and take the necessary precautions when canning tomatoes.

Equipment Needed to Can Tomatoes at Home

The equipment and supplies needed for canning tomatoes are basic to every canning process.

1. Pressure canner or water bath canner depending on the method you want to use.
   • If you don’t have a water bath canner, you can use a large pot that’s deep enough to cover the jars with one to two inches of water. Place a folded kitchen towel or a metal rack in the bottom of the pot so that the jars are not resting directly on the pot’s bottom.
2. Jar lifter to safely place jars into and take them out of the boiling water.
3. Jar funnel to make filling the jars easier and cleaner. You’ll want a funnel to fit the mouth of the jars you are using, either standard or wide mouth. I use only wide mouth canning jars.
4. Lid wand or tongs – If you are using Tattler lids or older metal lids, you will need a can lid wand or tongs to lift the lids out of the warm water. Although it isn’t necessary to heat the lids if you are using newer types of metal lids, old habits die hard and I still let them rest in hot water.
5. Thin spatula – I use bamboo – to remove air bubbles from the jar once they are filled prior to processing. Do not use metal utensils! Metal cutlery or spoon handles may cause scratches on the glass and I think they leave a metal taste in the tomatoes.
6. Large pot or I use my sink filled with ice and water to cool tomatoes after blanching to remove skins easily. You’ll also use it for heating tomatoes if you use hot pack method and for blanching them to remove skins.
7. Canning jars – All jars must be clean. You should also look for any damage, especially nicks or jagged jar rims that might cause sealing problems.
8. Lids and rings for all jars. The rings are to hold the lids in place during processing. Once the jars have cooled, I remove the rings from all my sealed jars. This isn’t necessary, it’s just a preference.
9. Ladle to fill jars.
10. Sharp knife to prepare tomatoes for canning. I find a serrated knife works best.
11. Towel or heat proof surface to place the processed on while they cool and seal. Use a towel that you don’t mind loosing to any tomato stains.

What Gets Put In The Jars?

• Tomatoes –  For every quart of tomatoes, you will need 2 1/2 to 3 1/2 pounds. For every pint, you will need 1.5 pounds.
• Fairchild’s Apple Cider Vinegar, Lemon Juice or Citric Acid Powder – 
  • I use Fairchild’s Apple Cider Vinegar because it is the only one that I know of that is not diluted. It is 25% acidity. Use 2 teaspoons for Pint jars and 1 1/2 Tablespoons for quart jars.
  • For safety, you must use bottled lemon juice and not fresh squeezed because of the standardized acidity in the bottled juice. I use only organic juice. Place one tablespoon of bottled lemon juice in each pint jar and two tablespoons in each quart jar.
  • Alternatively, use 1/2 teaspoon citric acid powder per quart, and 1/4 teaspoon per pint. Becasue citric acid is usually made from corn, I use one that is GMO-free made by a reputable company. Citric acid does not taste as strong as lemon juice, it’s what more people prefer to us.
  • Water bath canning requires a pH of 4.6 or below for safe results. The acidity of tomatoes is borderline so adding acid ensures safety when you can tomatoes using water bath canning method.
• Real Salt (optional) – I add salt to my tomatoes. Add 1 teaspoon per quart, 1/2 teaspoon per pint.

How to Prepare Tomatoes for Canning

Now that you’ve gathered all of your supplies, it’s time to start prepping the tomatoes.

There are two methods: raw pack and hot pack. The difference between the two is simply that in the hot pack method the tomatoes are brought to boiling for 5 minutes and kept simmering while you fill (pack) the jars. Raw packs are simply sliced and put into the jars once the skin is removed.

The method you choose is totally up to you. I learned the hot pack method and used it for years. Now I use the raw pack method because of the small amount of time it saves, but that’s one less burner I have to have on using gas and heating up the kitchen.

1. Wash your hands thoroughly.
2. Remove any bad spots or bruises from the tomatoes with a sharp knife.
3. If you are using hot pack method, core the tomatoes as you cut them into quarters or halves. Place the tomatoes in a large stockpot and heat until they reach boiling temperature. Remove from heat and following the directions below to remove the peels.
4. If you are using raw pack method, skip to blanching the tomatoes.

Blanch Tomatoes for Skin Removal

• Raw pack method – Fill a large pot with enough water to cover the tomatoes once they’re in the pot.
  • Bring the water to a boil then add the tomatoes.
  • Leave them in the boiling water for one minute or until the skins begin to split.
  • Quickly remove them and place them in an ice-water bath. The skins will split and slip right off.
  • Use a knife to scrape off any remaining skins.
• Hot pack method – After you have followed step 3 of preparing the tomatoes, pour them into a large colander placed in the sink.
  • Rinse with cold water then pour boiling water over the tomatoes.
  • Let them sit in the boiling water for 30 seconds then remove and place in an ice bath.
  • Use a knife to scrape off any remaining skins.
  • Return the tomatoes to the large pot and bring to a boil for 5 minutes. They should make enough juice to cover the tomatoes once you put them in the jars.
  • If you have to add more water to the jars to cover them, use boiling water.
  • Keep them at a simmer while you are working.

Freezing Tomatoes Before Canning

I like to freeze my tomatoes and wait until the weather cools off before I can them. I do this for a few reasons:

• It avoids heating up the kitchen in the summer
• It’s a good way to can all of them at once
• It makes removing the peeling easy. Freeze them whole or cut in half. Place them in gallon size freezer bags.
• When they thaw out, the skin slips right off. No blanching required.

How to Can Tomatoes: Step By Step

For both pressure canning and water bath canning follow steps 1 – 12 below.

1. Next wash all of your jars and lids. Some people use hot soapy water and then rinse well in hot water. I prefer to boil a pot of water and pour it over my jars and lids a couple of times.
2. Keep your jars warm. You can do this in the dishwasher, in the oven at low heat (200F), or in simmering water.
3. If your canner has a lift basket in it, elevate it by hanging it on the side of the canner as instructed.
4. Fill Jars with Tomatoes and Liquid
5. Add Fairchild’s ACV, bottled lemon juice, or citric acid to the jar.
6. Ladle the hot or raw packed tomatoes filling each jar to 1/2″ from the top.
7. Add salt to the top of the tomatoes. Do not stir the jars.
8. Gently run a spatula down the sides of the jars to remove any air pockets.
9. Adjust the liquid so there is only a 1/2″ headspace.
10. Wipe off the rim of each jar with a damp, clean towel then place a lid and ring on each jar and hand tighten them.
11. When you fill a jar with tomatoes, put it on the elevated rack in the canner.
    • When the rack is full or you run out of tomatoes, gently lower the rack into the water.
    • Lower one jar at a time into the boiling water if you are using a stockpot.
12. Make sure the jars are covered with 1-2 inches of water.

For Boiling Bath Canning

• Follow Steps 1 – 12 above
• Put the lid on the canner and bring it to a boil. After the water reaches a rolling boil lower the heat to maintain a medium-low boil and start timing. Use the altitude chart below for proper timing.
• When the processing time is done, turn off the stove and take the canner lid off. Let the canner cool down for 5 minutes.
• Remove jars from the canner and place them on a towel or heat proof surface to cool.

• Altitude adjustments for Water Bath Canning – Pints and Quarts are Processed the Same 
  • 0-1,000 ft – 85 minutes 
  • 1,001-3,000 ft – 90 minutes 
  • 3,001-6,000 ft – 95 minutes 
  • Above 6,000 ft – 100 minutes

For Pressure Canning

• Follow steps 1 – 12 above for preparing to can tomatoes.
• Place your filled jars in a warm pressure canner.
• Put the lid on the canner but do not put the weight on.
• Watch for the steam to come out of the vent pipe in the lid as the water boils.
• Once the steam begins escaping, set a timer for 10 minutes and allow the steam to vent the full time.
• After the full 10 minutes, put the weight on the lid.
• Check the chart below to ensure you use the proper weight for your altitude.
• Once the weight is applied, the steam will stop, the vent will seal and the pressure will begin to build.
• When the pressure reaches the level required for your altitude, you will start your timer.
• Process for the full time required at the correct pressure. You may need to adjust the heat to maintain the correct pressure for the entire time. So keep an eye on it.
• When the processing time is finished, turn off the heat.
• Do Not remove weight until after the canner has cooled completely.
• Allow the canner to rest undisturbed until the pressure returns to zero. Do not try to hasten the cooling process in any way.
• After the pressure is returned to zero, remove the weight and wait another 5 minutes.
• Remove the lid and let out any remaining steam being careful to open the lid away from you to avoid steam burns on your face or hands.
• Lay the lid back on top of the canner leaving it slightly ajar and wait 5 minutes more.
• Remove the lid from the canner and use your jar lifter to carefully remove the hot jars from the pot.
• Place them on a towel or heat proof surface to cool.

Altitude and Pressure Adjustments for Pressure Canning – Process pints or quarts for 25 minutes, adjusting for altitude. 

• Altitude Adjustments for Dial Gauge Canner
  • 0-2,000 ft – 11 pounds
  • 2,001 – 4,000 ft – 12 pounds 
  • 4,001 – 6,000 ft – 13 pounds 
  • 6,001 – 8,000 ft – 14 pounds 

• Altitude Adjustments for Weighted Gauge Canner
  • 0-1,000 ft – 10 pounds 
  • 1,001 – 8,000 ft – 15 pounds 
    • Adapted from: The National Center for Home Food Preservation – May 2021

How do I know my lids are sealed?

You’ll hear that lovely “ping” as the jars begin to cool but to know for certain which are sealed it’s easy to verify.

• To check the lids, gently press the middle of the lid.
• The center should be drawn tightly down without any flex.
• If the lid is loose, place the jar in the refrigerator and use it within 48 hours.

You can double-check the seal as you remove the rings. Once you remove the ring, gently try to lift the lid with your fingers. If it comes off or moves, then the seal is not good.

How to Store Canned Tomato Jars

Once you’re sure the seals are good, wipe off the jar and lid with a clean, damp cloth. Label and store in a cool, dark, dry location. Avoid placing them in sunlight as this will bleach the color from the tomatoes.

Properly canned tomatoes are good for at least one year. I use them within three years, but I seldom have any that last that long.

Safely Preserving the Tomato Harvest

Unfortunately, there are videos and websites on the internet that teach improper canning processes. These might land you in a lot of trouble and woe. Be sure your source of information is trustworthy.

A pH of 4.6 or lower is required to prevent botulism growth. Many tomato cultivars have a higher pH nowadays than 4.6.

This is why, in all cases, safe canning recipes always include extra acid to canned tomatoes that will be water-bath canned. If food in a jar is above 4.6 pH, it might become a breeding ground for botulism, which can be deadly.

I know many people despise the amount of time needed to can safely and they use this as a reason not to can. We invest months into growing organic heirloom tomatoes to have healthy food. So for me to spend a little extra time making sure they are properly preserved is well worth the peace of mind and assurance that we are eating the most nutritious food we can.

Summary

Tomatoes are the only vegetable we still preserve by canning. We mostly dehydrate our garden produce. It’s easy to do and they taste delicious. The only other thing we pressure can is meat.

By following the safety guidelines in this article and the easy step-by-step instructions, you will have tomatoes for all those delicious soups, casseroles, and pasta dishes your family loves.

As always, we’re here to help.