Homemade fermented ketchup is a flavourful and healthy condiment. It is surprisingly easy to make, and you get to control the amount of sugar, which is a good thing if, like me, you use the red sauce to encourage your kids to eat their dinners. (Apparently ketchup tastes good on broccoli.)
I have made ketchup with fresh roma tomatoes and with tomato puree, depending on whether it’s tomato season. The first recipe is written for tomato paste, since that’s easier for most people. But if you have a nice crop of roma tomatoes, I recommend making ketchup with fresh tomatoes, since the flavour is far superior. The recipe for using whole tomatoes at the bottom of the page.
Fermented ketchup?
I make fermented ketchup because I like all things fermented. It also increases the shelf-life of homemade ketchup. However, the recipe can be made without fermentation. Simply skip the fermenting step and use the ketchup right away.
If you aren’t going to ferment the ketchup, then I recommend only keeping 1 cup of ketchup in the fridge at a time, and freezing the rest. Because it is a low sugar ketchup made with real vegetables, it won’t last as long as store-bought varieties.
PrintFermented Ketchup

Homemade ketchup is surprisingly easy to make. It’s also much more flavourful and healthier than store bought ketchup! This ketchup is mixed with a probiotic culture for an extra dose of goodness.
- Prep Time: 5 minutes
- Cook Time: 30 minutes
- Total Time: 35 minutes
- Yield: 4 cups 1x
- Category: Condiment
- Method: Fermented
- Cuisine: American
Ingredients
Main Sauce
- 3 cups tomato paste
- 1/3 cup honey (see notes)
- 1 cup cider vinegar
- 1 cup water
Tied in a cheesecloth:
- 1 onion, diced
- 2 cloves garlic
- 1 cinnamon stick
- 1/2 tsp each of allspice berries, cloves, mustard seed, black pepper
- 1 bay leaf
For fermenting
- 1 tsp salt, to taste
- 1/4 cup of culture (see notes)
Instructions
- Mix together the tomato paste, honey vinegar in a large pot.
- Combine the spices and the finely diced vegetables into spice bag or tied up in a cheesecloth. Submerge the flavours in the pot with the tomato paste and vinegar.
- Bring to a boil and simmer for 30 minutes. Stir it occasionally to prevent the tomato paste from sticking to the bottom of the pot.
- Discard the cheesecloth of spices, and add salt to taste.
- Put the ketchup into a sterilized glass jar for fermenting. Put the lid on and allow to cool to room temperature (about 2 hours.)
- Stir in the culture and store it somewhere cool and dark to ferment for 2 days.
- Store it in the fridge and use within 2 months, or freeze smaller portions for future use.
Notes
- The amount and type of sweetener is optional. I use 1/3 cup of honey, however, you could use brown sugar or maple syrup. If you want to use a low calorie sweetener, then add it after fermenting.
- This ferment works well with a vegetable starter (affiliate link,) cider vinegar or kombucha. Miso will add a bit of umami to your ketchup.
- If you ferment in two mason jars, then you can try out two different types of starters. Experimentation is always fun!
Keywords: probiotic, healthy, catsup, red sauce, vegan, gluten free, low sugar, refined sugar free, summer, fall
Whole Tomato Ketchup
Make whole tomato ketchup in September when tomatoes are abundant. It takes about 2 hours to cook the tomatoes down, so it’s a good thing to do while you watch a movie.
Follow the recipe above, but make the following changes:
- Replace the tomato paste with 7 lbs roma tomatoes, chopped, 3 onions diced and 1 red bell pepper, diced.
- Mix the vegetables in a large pot, and simmer over medium heat until the vegetables are very soft.
- When the vegetables a coked, push them through a food mill
, and return to the pot as a replacement for the tomato puree.
- Boil with the spices for an additional hour until the ketchup has thickened.
- Proceed with the fermenting as described in the recipe above.
Hi Emillie,
Do you mean tomato “paste”, or “sauce”?
I do mean paste… the liquid comes in the culture, water and vinegar. I’ve also made ketchup by cooking down whole tomatoes, but it took hours! Using paste is quicker. If it seems like a lot (which it is!) just halve the recipe.
Could I use blended dates as my sweetener?
Dates are my favourite sweetener. And they’ll definitely work in this recipe! You could add them to the boil so they soften before pureeing. Enjoy!