How To Preserve Fresh Tomatoes, Step By Step

Garden-fresh tomatoes are a summertime treat, but if you preserve your tomatoes properly, you can enjoy them all year long—including in the dead of winter. Find a simple preserved tomato recipe, gather your short list of ingredients and follow the directions below to get summer flavours long after the warm weather's disappeared.

How to preserve tomatoes

Start boiling your water

Boiling water in the canner usually takes a while, so get it started right away. Fill a very large pot that can accommodate jars (each must have space around it) with at least two inches of water to cover. This pot is used only for processing filled jars (use another large pot for cooking the preserves).

Clean the jars

Make sure the jars and screw bands are perfectly clean; a cycle through an empty dishwasher is ideal. Always use fresh flat lids.

Prep and cook tomatoes

Get the good stuff ready to fill the jars! For tomatoes, core, blanch, then drop into ice water. Use a knife to pull the skin away easily.

Fill the jars

Use a clean canning funnel and ladle to fill each jar. Always follow the recipe’s instruction for headspace (the space between the level of fruit and the sealing lid). Wipe jar rims with clean paper towel. Carefully place the flat sealing lid on top with a magnetic stick. Tighten the screw band only just enough for it to stay on the jar (it has to leave enough room for the air to escape).

Related: Preserved Tomatoes Recipe

Processing

Use canning tongs to carefully place the jars into the canner of boiling water. Filled jars must be covered by at least two inches of water. Start the timer on the processing when the water comes to a full rolling boil. Keep the water boiling for the entire processing time.

Check the lids

Let processed jars stand at room temperature for 24 hours. Check that lids have sealed properly by pressing them. They should be flat and not pop up. Any jars that haven’t sealed can be stored in the fridge and used within two weeks.

Essential canning tools

1. Canner and rack: The rack prevents jars from touching one another, which is important for proper preservation.
2. Canning tongs: The coated handles and special shape make lifting jars in and out of water easy.
3. Canning funnel: The wide mouth fits snugly inside jars so filling is easy and neat.
4. Magnetic stick: A magnetic stick quickly picks up flat metal lids so you don't contaminate them with your fingers.
5. Jars, lids and labels: Always use jars and lids designed for canning. Add labels once your preserves are at room temperature.

Essential canning ingredients

1. Bottled lemon juice: It's the only way to ensure a standardized acidity.
2. Sugar: Use regular white granulated sugar to make sure results are consistent
3. White vinegar: The most common acid used in preserving. Don't substitute another type.
4. Pectin: A natural fibre found in fruit that helps jams and jellies set. You can go without it but you'll have to cook preserves longer, which makes them less juicy and less fresh-tasting. Pectin* also lets the flavours of the fruit shine through. Many fruits (such as pears) are naturally high in pectin; you can even make your own by cooking down apple peels and cores.

*You can find powdered and liquid pectin at hardware and grocery stores, especially in the summer. Use whichever the recipe calls for, as the two react differently.

Originally published 2017; Updated 2023.