Easy Slow Cooker Summer Tomato Jam
Tomato jam? Hmmm, that’s a new one for 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 freezing some goodies to enjoy later, which sure sounded good and easy! This version is for the refrigerator or freezer only, not pantry canning.
This deep red tomato jam will be so pretty and festive on my table! I need to think of a little green garnish; 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 ripe tomatoes, discarding any damaged portions, then cut them in quarters or smaller. The skins may be left on for this refrigerator/freezer recipe. 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 the tomatoes in your slow cooker and stir in the lemon juice, brown sugar, salt, cinnamon, cloves, ground ginger, and optional red pepper flakes. Cook on high, covered until the mixture is simmering, then let moisture escape as described below. Allow about twelve to fifteen hours, but check earlier and use the thick, spreadable consistency rather than the clock as your guide. The fifteen-hour cook time on the card is an estimate, not a guarantee.
The card uses cinnamon, ground ginger, cloves, and optional red pepper flakes, with brown sugar and lemon juice. Adjust the dry spices to taste in this refrigerated or frozen version.
Lemon juice balances the sweetness here, but adding acid does not by itself make this recipe safe for canning. Do not use the old water-bath directions or assume ingredient substitutions make the jam shelf-stable.
Once the tomatoes are simmering, leave the lid ajar so moisture can escape, following your slow cooker’s instructions. Stir regularly and check that the mixture continues to simmer and thicken. If it stays too watery, transfer it to a wide saucepan and simmer uncovered, stirring often, until spreadable. Never put a stoneware slow-cooker insert directly on a burner.
Watch and stir more frequently as the jam thickens, scraping the bottom and sides, because the sugar can scorch. Do not leave the reducing jam unattended overnight. A small spoonful cooled on a chilled plate should hold its shape without a watery rim; the jam will thicken further as it cools.
Put The Yummy Tomato Jam Into Jars To Store For Another Day
This batch cooked down to about 4 cups, enough for four half-pint containers before allowing freezer expansion space. The yield varies with the tomatoes and how much liquid evaporates. Use clean, food-safe containers.
Divide the cooked jam into small, shallow containers and refrigerate promptly at 40°F or below, within two hours of finishing cooking, or within one hour if the room is above 90°F. Do not leave the whole hot batch on the counter to cool.
Use refrigerated jam within four days of cooking, or freeze it for longer storage. This conservative limit follows USDA guidance for cooked leftovers; this particular formula has not been validated for extended refrigerator storage.
For freezing, use freezer-safe containers or jars and leave the expansion space recommended by their manufacturer. Label with the cooking date and freeze promptly. Use within three months for best quality.
Thaw frozen jam in the refrigerator, not on the counter. Keep it at 40°F or below and use within three to four days after thawing.
Do not water-bath can this slow-cooker recipe. A sealed lid or a popping sound does not establish that a food is safe at room temperature.
For pantry-stable tomato jam, follow the National Center for Home Food Preservation’s tested spiced tomato jam recipe exactly, including its different ingredients, peeled-tomato preparation, pectin, jar sizes, and altitude-adjusted processing. Do not apply that processing time to this recipe.
It’s gorgeous stuff, isn’t it?
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 chilled jar as a gift, kept cold during transport and labeled “Keep refrigerated” with its four-day use-by date. Include crackers, 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 top of bean soup.
Oh wait, that’s six. What will you do with your tomato jam?
Slow Cooker Tomato Jam
A sweet, sticky, spicy slow-cooker tomato jam for the refrigerator or freezer only. Not for canning or room-temperature storage. Cooking time and yield are estimates.
Ingredients
- 4 pounds ripe, meaty tomatoes, such as Roma
- 2 1/2 cups brown sugar
- 1/3 cup lemon juice
- 1 teaspoon ground cinnamon
- 1/4 teaspoon ground cloves
- 1/2 teaspoon salt, plus more to taste
- 1/4 teaspoon ground ginger
- 1/2 teaspoon red pepper flakes (optional)
Instructions
- Wash and core the ripe tomatoes, discard damaged portions, and quarter them. You may leave the skins on for this refrigerator/freezer recipe.
- For chunky jam, chop finely by hand or pulse a few times in a food processor, working in batches.
- For smoother jam, process in batches until the tomatoes are well mashed.
- Put the prepared tomatoes into a slow cooker, following its recommended fill level, and set it to high.
- Stir in the brown sugar, lemon juice, salt, cinnamon, cloves, ground ginger, and optional red pepper flakes. Cover until the mixture is simmering.
- Once simmering, leave the lid ajar to let moisture escape, following the appliance instructions. Cook until thick and spreadable, stirring regularly. Allow about 12 to 15 hours, but check earlier; the 15-hour cook time is an estimate and will vary with the tomatoes and cooker.
- Watch and stir more frequently as the jam thickens so it does not scorch; do not leave it reducing unattended overnight. A small spoonful cooled on a chilled plate should hold its shape without a watery rim. If the mixture stays too watery, transfer it to a wide saucepan and simmer uncovered, stirring often, until thick. Never place a stoneware slow-cooker insert on a burner.
- Divide into small, shallow containers and refrigerate promptly at 40°F or below, within 2 hours of finishing cooking, or 1 hour above 90°F. Use within 4 days of cooking, or freeze promptly in freezer-safe containers with the expansion space recommended by the manufacturer. Label with the cooking date; use frozen jam within 3 months for best quality. Thaw in the refrigerator and use within 3 to 4 days after thawing. This recipe is not validated for canning: do not water-bath process it or store it at room temperature.
We’re so happy that people are getting back to canning, freezing, and preserving fruits and vegetables. It is such a rewarding thing to do, and you can actually see tangible evidence of what you have done! Here are some of our most popular recipes! How To Freeze Corn, Strawberry Rhubarb Jam, How To Freeze Tomatoes Whole, and Homemade Apple Butter.
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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!
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! 😢
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.
Loralei, you are so right!! I will amend the instructions right away; thank you!
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! 😊
Can you convert these instructions to the InstaPot or CrockPot Express? What about doubling the recipe?
It is great on bacon, egg and cheese biscuit or sandwich!
Looks great. Could you make this substituting green tomatoes without any other changes?
I would think so but I’ve never tried it. It sounds good and would look pretty! Would you let us know how it goes?