Tomatoes are the essence of summer, bursting with flavor and nutrients that are perfect for everything from sauces to soups. But as the season changes and the fresh supply dwindles, canning tomatoes is an excellent way to enjoy this delicious fruit year-round. This guide will walk you through the entire process, ensuring you can preserve tomatoes with confidence, whether you’re a beginner or an experienced home canner.
Why Can Tomatoes?
Canning tomatoes is not only a way to preserve their peak flavor but also an excellent method for reducing waste. Home-canned tomatoes are versatile, healthy, and free from preservatives often found in store-bought versions. Whether you’re making a rich pasta sauce, a hearty stew, or a refreshing salsa, having canned tomatoes on hand saves time and adds depth to your dishes.
Supplies You’ll Need
Before you start, gather the following supplies:
- Fully ripe tomatoes: You’ll need about 1 1/2 pounds of fresh tomatoes to fill a pint jar and 3 pounds to fill a quart jar.
- Bottled lemon juice or citric acid powder: This is crucial for safely preserving tomatoes.
- Pint or quart canning jars with lids: Make sure they are specifically designed for canning.
- Pot with lid and trivet or pressure canner: Choose based on your preferred canning method.
- Jar lifter tongs: Essential for safely handling hot jars.
Step 1: Inspect the Jars
The first step in canning is ensuring that your jars are in perfect condition. Carefully inspect each jar for cracks or imperfections, paying special attention to the rim. Any damage could lead to sealing failures, which would compromise the safety of your canned tomatoes. Discard any jars that are not in pristine condition.
Step 2: Place the Jars in a Canning Device
Depending on your canning method—either water bath or pressure canning—you’ll need to prepare your jars differently.
- For water bath canning: Place a silicone trivet or rack at the bottom of a large pot or stockpot. This prevents the jars from sitting directly on the bottom of the pot, which could lead to breakage. Place the jars in the pot and fill it with enough water to fully cover them.
- For pressure canning: Add about 2 inches of water to your pressure canner. Place the jars inside, making sure they are upright, and then fill them with water to prevent them from floating during the canning process.
Step 3: Bring the Water to a Simmer
With the jars in place, slowly bring the water to a simmer. This gradual heating helps prevent thermal shock, which can crack the jars. While the water heats, you can start preparing your tomatoes.
Step 4: Wash and Cut the Tomatoes
Wash your tomatoes thoroughly under running water to remove any dirt or pesticide residue. Using a paring knife, cut an X at the bottom of each tomato. This small cut will make the skin easier to remove later on.
Step 5: Blanch the Tomatoes
Blanching is a quick and easy way to peel tomatoes. Bring a large pot of water to a rolling boil and, working in batches, drop in a few tomatoes at a time. Blanch them just until the skins start to curl up where you scored them—this should take about 30 seconds, depending on the size of your tomatoes.
Step 6: Dip the Tomatoes in Ice Water
Using a slotted spoon, remove the tomatoes from the boiling water and immediately plunge them into an ice water bath. The sudden temperature change will stop the cooking process and make the skins easier to remove. Once cooled, place the tomatoes in a colander set over a bowl to drain any excess liquid. When they’re cool enough to handle, remove the skins and cores, and cut larger tomatoes in half.
Step 7: Cook the Tomatoes
Transfer the peeled and cored tomatoes back into a pot, along with any juice that has accumulated. Add just enough water to cover them and bring to a boil. Reduce the heat to medium-low and cook the tomatoes for about 5 minutes. This cooking step is crucial as it helps to reduce the amount of air in the tomatoes, which can affect the canning process.
Step 8: Remove the Jars
Using your jar lifter tongs, carefully remove the jars from the simmering water and pour out the water from inside the jars. Place the jars on a damp tea towel to prevent them from cracking when you fill them with hot tomatoes. Keep the water in your canner or pot simmering; you’ll need it for processing the filled jars.
Step 9: Add Bottled Lemon Juice or Citric Acid
Tomatoes are naturally acidic, but not quite acidic enough to prevent the growth of bacteria during storage. To ensure safety, add bottled lemon juice or citric acid to each jar before filling it with tomatoes.
- For pint jars, add 1 tablespoon of bottled lemon juice or 1/4 teaspoon of citric acid.
- For quart jars, add 2 tablespoons of bottled lemon juice or 1/2 teaspoon of citric acid.
This step is non-negotiable; it ensures that your tomatoes remain safe to eat even after long storage.
Step 10: Fill the Jars with Tomato Mixture
Using a ladle, carefully fill each jar with the hot tomato mixture, leaving about 1/2 inch of headspace at the top. This space allows for the expansion of the contents during processing. Use a small spatula or a non-metallic utensil to gently push the tomatoes down, releasing any trapped air pockets. Ensure the tomatoes are fully submerged in liquid; if necessary, add more of the cooking liquid.
Step 11: Wipe the Rims of the Jars
Before sealing, wipe the rims of the jars with a damp paper towel to remove any residue. This ensures a good seal, which is essential for long-term preservation.
Step 12: Seal the Jars
Place new lids on each jar, then screw on the bands until they are fingertip tight. Be careful not to over-tighten, as this could prevent the lids from sealing properly.
Step 13: Process the Jars
Now it’s time to process the jars, which involves heating them to a temperature that destroys any harmful microorganisms.
- For water bath canning: Place the jars back into the water bath canner, ensuring they are covered by at least 1 inch of water. Process pint jars for 40 minutes and quart jars for 45 minutes, keeping the water at a steady, gentle boil throughout. If you live at an altitude above 1,000 feet, you’ll need to adjust the processing time according to your altitude.
- For pressure canning: Follow the manufacturer’s directions for your specific model. In a dial-gauge pressure canner, process both pint and quart jars at 11 pounds pressure for 10 minutes. In a weighted-gauge pressure canner, use 10 pounds of pressure for the same time. Venting the pressure canner as per the manufacturer’s instructions is crucial to ensure a safe canning process.
Step 14: Remove the Jars
After the processing time is complete, turn off the heat.
- For water bath canning: Let the jars sit in the hot water for an additional 5 minutes before removing them. This step helps prevent siphoning, where liquid could be drawn out of the jars during cooling.
- For pressure canning: Allow the canner to depressurize fully before opening it. Remove the jars carefully and place them on a damp tea towel. Let the jars cool undisturbed for 24 hours to allow the seals to set properly.
Final Steps: Check the Seals and Store
After the jars have cooled for 24 hours, check the seals by pressing down on the center of each lid. If it doesn’t pop back, the jar is sealed. Remove the bands and store the jars in a cool, dark place. Properly canned tomatoes can last up to a year, providing you with the taste of summer even in the depths of winter.