Sauces and Condiments

How To Make Easy Slow Cooker Tomato Jam


Sharing is caring!

Easy Slow Cooker Summer Tomato Jam

tomato jam with cream cheese on crackers

Tomato jam? Hmmm, that’s a new one on me, but the idea I could use up a whole flat of tomatoes AND do it in a slow cooker was very appealing! I love to put up some goodies to enjoy when the snow flies and this sure sounded both good and easy!

This deep red jam will be so pretty and festive on my table! I need to think of a little green garnish; then it will be perfect! And, it will be something new and different for a party!

I’m already thinking about how much my guests will enjoy it in December when we get together for our annual cookie exchange!

This recipe works best when you use a meaty tomato like a Roma. They are not quite as juicy as a slicer, so they cook down to a “jammy” consistency more easily.

Wash and core the tomatoes, then cut them in quarters or even smaller. I put mine in the food processor and pulsed them until they were pretty well mashed. If you prefer chunkier jam, go for it, chop them finely or go easy on the Cuisinart!

Next, put them in your slow cooker, add the lemon juice, brown sugar, salt, and spices and let it all cook on high all day or overnight. It will take somewhere between twelve and fifteen hours for the tomatoes to cook down to a thick, sticky jam, depending on your slow cooker. Your whole house will smell amazing while it cooks.

The spices you choose are up to you. Typically, this combination of cinnamon, ginger, and cloves, along with brown sugar and lemon or lime juice, is pretty common. I have seen cumin, red pepper flakes, and jalapenos used, too.

Some cooks use vinegar instead of lemon or lime juice. The jam does need a certain amount of acidity to balance the amount of sugar used. This recipe does not make a large batch, so you can experiment to find your favorite combo.

cooking tomato jam

If the tomatoes are especially juicy, you can leave the lid off the slow cooker, especially at the beginning of the cooking time to allow moisture to escape. You will need to check on your project from time to time to make sure the jam is getting thicker.

Watch the tomatoes closely toward the last two hours because the mixture can burn when the liquid evaporates. I may or may not be speaking from experience. πŸ˜†

Now Put The Yummy Jam Into Jars And Get It Ready To Store For Another Day

This batch cooked down to 4 half-pint jars (after I got done sampling.) Put the jam in glass canning jars with a flat and a sealing ring you have hand-tightened snugly.

You can stop at this stage and put the jars in your refrigerator. The jam will be good to eat now and for about two weeks. If you want to store it in your freezer, leave a little bit of extra space in the jar because the jam will expand as it freezes. It will keep in your deep freeze for about a year.

If your freezer space is limited, the jam will be shelf-stable for a year or more by giving it a simple hot water bath treatment. Bring a large pot of water to a boil. The water needs to be deep enough to cover the top of each jar by an inch or more. We have hard water, so I add about a tablespoon of vinegar to the pot. That way, lime doesn’t form on the jars.

Carefully lower the jars into the boiling water with a canning jar lifter. You can find one in the kitchen gadget department. You need one to get a good grip on the jars. They are not expensive and will probably last a lifetime.

Leave the jars in the boiling water bath for 15 minutes to kill any bacteria and to make the jam so hot it will form a vacuum seal in the jar when it cools. Set a timer.

When the timer goes off, remove the hot jars from the canner with the lifting tool. Set each jar gently on a cooling rack. Pick an area where they can cool naturally without touching them. I know it’s tempting, but let them cool hands-off.

There should not be a fan or breeze blowing on them. As each jar seals, you will hear a satisfying “ping” sound as the lid pops down. If the jars don’t seal, refrigerate or freeze them.

It’s gorgeous stuff, isn’t it?

looking into jar of tomato jam

5 Delicious Things You Can Do With Tomato Jam

So now that you have your first few jars of tomato jam, what do you do with it?

  • Give a jar as a gift. Include a package of good crackers, some cream cheese, and a cute spoon.
  • Slather it on a burger.
  • Put it inside a grilled cheese sandwich.
  • Whisk it into a vinaigrette
  • Stir some into a pot of baked beans.
  • Plop a dollop on bean soup.

Oh wait, that’s six. What will you do with your tomato jam?

tomato jam jar
Yield: Four 8-ounce (half-pint) jars

Slow Cooker Tomato Jam

Easy Slow Cooker Summer Tomato Jam

A sweet, sticky, spicy jam you make in a slow cooker. Can be refrigerated, frozen, or canned.

Prep Time 10 minutes
Cook Time 12 hours
Total Time 12 hours 10 minutes


  • About 4 pounds of meaty tomatoes
  • 2 1/2 cups brown sugar
  • 1/3 cup lemon juice
  • 1 tsp cinnamon
  • 1/4 tsp ground cloves
  • 1/2 tsp salt or more to taste. (I used more.)
  • 1/4 tsp ground ginger (or you can use fresh ginger, peeled and cut into small pieces.)
  • 1/2 tsp red pepper flakes (optional)


  1. Wash and core the tomatoes, then cut them in quarters or even smaller.
  2. For chunky jam, chop finely by hand or pulse a few times in a food processor in batches.
  3. If you like a smoother jam, pulse in a food processor in batches until the tomatoes are mashed.
  4. Put tomatoes into a slow cooker set on high.
  5. Add lemon juice, salt, brown sugar, and spices.
  6. Cook on high for 12 to 15 hours until the mixture has a jam-like consistency.
  7. Watch closely toward the end of the cooking time. When the liquid evaporates, the mixture can burn.
  8. Ladle into jars and refrigerate, freeze, or process in a boiling water bath for 15 minutes. Instructions are in the blog post.
Easy Slow Cooker Summer Tomato Jam

More recipes from us

Tomato Pie
Tomato Pie

4 Reasons You Should Freeze Some Sweet Corn This Summer

Danish Style Cucumber Salad

How To Make The White BBQ Sauce That’s Fascinated Us Since 1925

German Sauerkraut Casserole With Bacon And Brown Sugar

If you like these recipes, you are our people! You can check some related articles below or search via categories on the right. But, be warned; you will be on here for hours. Enjoy! 

So, please share this recipe on your social media accounts like Facebook, Instagram, Twitter, and Pinterest. We would be honored and ever so grateful; thank you!


Sharing is caring!


  1. Linda Fashingbauer

    Do you also peel the tomatoes when making the tomato jam? It doesn’t say but I would think so. Thanks

    • I didn’t peel the tomatoes. If you prefer to peel them, that’s fine, too. When I ran them through the food processor and slow-cooked them for hours, the peel was not at all noticeable. I hope this helps! Good luck!

  2. I made this since I like to use my slow cooker. It tasted great however it never jelled into a jam. I cooked it for 15 hours. Anyone else have this issue?

    • I’m sorry as I can be; I should have mentioned you can leave the lid off the crockpot for much of the cooking time to reduce the moisture. I am amending the recipe instructions! You can still cook it down by putting it in a saucepan and simmering it uncovered. Let me know; so sorry! 😒

  3. Instructions should note that the crockpot lid isn’t to be used, to allow the moisture to escape, which enables the jam to reduce and gel.

  4. The instructions don’t say when to add the brown sugar.

    • Next, put them in your slow cooker, add the lemon juice, brown sugar, salt, and spices and let it all cook on high all day or overnight.”

      I apologize I missed that on the recipe card. I will edit it shortly! Thank you for letting me know! 😊


Leave a Comment

Your email address will not be published. Required fields are marked *