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Slow Cooker Homemade Ketchup

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This slow cooker homemade ketchup is perfect for using up all those leftover summertime tomatoes. Why buy the bottled stuff when you can make it yourself?

Slow Cooker Homemade Ketchup jars stacked on top of each other.

Brandy lives close to me and she holds the unique distinction among fellow food bloggers of having been to my house. That she knows what a mess it can be, and yet still asked me to guest post on her blog, is a testament to her awesomeness.

Brandy and I live in an area that’s just full of amazing farms. So while I do have my own garden and grew quite a lot of my own tomatoes this summer, I usually head to one of my favorite local farm stands and pick up inexpensive “utility-grade tomatoes” when I want to do any canning.

I bought the tomatoes you see below the day before Hurricane Irene. I figured that if we didn’t lose power, I could do some serious tomato preserving during the storm.

A box full of tomatoes.

Fortunately for us, our power did stay on, and I spent the day creating jars and jars of tomato products to see us through the winter. One of the recipes I made was this slow cooker ketchup.

Homemade ketchup you say? Why would anyone bother with that?

Well, this version is spicy and delicious. It’s not like anything you can buy. It’s made in a crockpot, so apart from peeling and seeding the tomatoes, you really don’t have to do much work. Plus it’s fun to be able to say you made your own ketchup 🙂

ps I will be savoring these jars all the more since the farm where I bought them lost the rest of their tomato crop in the storm and subsequent flooding.

Slow Cooker Homemade Ketchup in a jar.

More tomato recipes

Slow Cooker Homemade Ketchup via Nutmeg Nanny

Slow Cooker Homemade Ketchup

Yield: 3 (8 ounce) jars
Prep Time: 2 hours
Cook Time: 12 hours
Total Time: 14 hours

This slow cooker homemade ketchup is perfect for using up all those leftover summertime tomatoes. Why buy the bottled stuff when you can make it yourself?


  • 6 pounds ripe tomatoes
  • 1/2 large yellow onion, peeled and roughly chopped
  • 2 fat cloves garlic, peeled
  • 1/2 cup sherry or apple cider vinegar
  • 1/2 cup dark brown sugar
  • 2 tablespoons jarred capers, with brine
  • 2-3 teaspoons salt (to taste)
  • 1 teaspoon ground cinnamon
  • 1 teaspoon ground cumin
  • 1 teaspoon paprika
  • 1 teaspoon red pepper flakes
  • 1/2 teaspoon ground white pepper
  • 1/4 teaspoon allspice


  1. Blanche the tomatoes in boiling water for 1-2 minutes.
  2. Remove with a slotted spoon to a bowl, allow to cool a bit, then peel them.
  3. Set the tomatoes in a colander over a clean bowl. Core them and cut into quarters, then squeeze as much liquid and as many seeds out of the tomatoes as possible.
  4. Process the drained tomato chunks with the onion and garlic in a blender.
  5. Pour the tomato puree into your crockpot and add the rest of the ingredients. Stir well to combine.
  6. Cook on high for 10-12 hours. It will reduce, thicken and darken considerably during this time. Stir the ketchup occasionally, and feel free to taste and adjust the seasonings as it's coming along.
  7. After the ketchup has finished cooking, allow it to cool before processing it in a blender for a minute or two to smooth it out.
  8. Bring back to a boil in a small pot on the stove, then ladle hot ketchup into sterile 8 ounce jars (I used 3), leaving 1/2 inch headspace.
  9. Remove any air bubbles by running a small knife around the inside of the jars.
  10. Wipe rims, place lids on jars, and screw on the bands to fingertip tight.
  11. Process in a boiling water bath for 10 minutes, then let jars rest for 5 minutes before removing from the water.
  12. Cool at room temperature overnight, then check to make sure the jars have sealed.
  13. Once opened, the ketchup should last for a couple of weeks.

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Rachel @ Not Rachael Ray

Wednesday 28th of September 2011

Oh yum! This looks amazing! I definitely want to try this.

Mal @ The Chic Geek

Wednesday 28th of September 2011

Homemade ketchup! What a great idea

Jersey Girl Cooks

Wednesday 28th of September 2011

I love this idea. Next summer I am going to make homemade ketchup.

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