Canning tomatoes is a simple, satisfying process. Enjoy the taste of summer all winter long by preserving your harvest!
What you’ll need:
Tomatoes: You can use any kind you like - keep in mind you’ll get more jars per pound using a tomato with fewer seeds and juice (try paste tomatoes!). As is true of all cooking, the higher quality produce you use, the better your canned goods will be.
Especially this time of year as the tomato season is winding down, check in with local farmers to buy in bulk!
You’ll need about 3 pounds of tomatoes per 1 quart of canned tomatoes.
Canning jars
Canning lids & rings
lids can only be used once, as the seal will not work a second time.
Rings can be used over and over.
1 large pot - deep enough that your jars will be submerged and inch or two in water.
One cutting board & knife
Slotted spoon
Canning tongs with grips
Funnel - with a large enough opening at the base to allow your tomatoes to pass through
Ideally 2 or 3 large bowls
One to hold your skinned tomatoes
One to move the tomatoes to once they are diced
One to catch the skins, seeds, and juice. You can strain this later and use it!
Bottled Lemon Juice - Tomatoes are a high-acid food, but the actual level of acidity varies by variety. Add 2 tb. of bottled lemon juice per quart jar (bottled have a standardized pH) to ensure bacteria won’t grow in your preserves.
Salt - for flavor! Add 1/2 tsp to a quart jar.
To keep things clean and organized, it’s helpful to complete one step for all your jars or tomatoes before moving on to the next.
Be sure to wash your hands and all your surfaces before you begin.
Part One: Prep your jars
Bring water to a boil to sterlize your jars. They’ll need to be completely submerged 10 minutes.
You can add hot water from your pot to a small bowl on top of the rings and lids, but don’t boil them.
Don’t toss that water! You can use it for your hot water bath in just a bit.
Line them up and add your lemon juice and salt. (This saves you the moment later, when you wonder if you added juice and salt to that jar or not.)
Part Two: Prep your tomatoes
Remove the skins
Create a small x on the bottom of each tomato with a paring knife.
Submerge them in boiling water for 30 seconds
using a slotted spoon, remove them and add them to a large bowl
Once they are cool enough to handle, peel away the skin
Core & dice (if desired)
You could always can the tomatoes whole, chop them into quarters, dice them, or crush them. Keep in mind how you typically use tomatoes when you cook.
Part Three: Fill your jars
Using a funnel, fill your jars - pressing down to remove air pockets.
Depending on the type of tomato, the jar may fill with juice. If not, use water or some of your reserved tomato juice to fill the jar with 1/2” of head space at the top.
Wipe down the rim of the jar so it is clean. This is critical to a good seal.
Add the lid and secure with a ring.
Part Four: Water Bath
Using the tongs, submerge your jars in water and bring it to a boil for 45 minutes.
Keep an eye on your water bath - make sure the jars are submerged an inch or two the entire time. You may have to add a little water as it evaporates.
Before time is up, identify a place to let your jars rest while they cool undisturbed and preferably not too far from your boiling water. Put down a dish towel - your hot jars will be more susceptible to cracking when they are super hot, so have a soft place for them to land
Using the tongs, remove the jars with care. Place them on your prepared towel, spaced so they aren’t touching.
Usually you’ll hear the pop of the lids as they seal. After they’ve cool, test the top - if the center does not depress it has sealed and will keep for the next year on your shelf!
If it has not sealed/you can depress the center of the lid just use the tomatoes in the next few days.
For additional resources on canning of all kinds, we recommend visiting the K-State Extensions website!