Homemade, Fermented Ketchup

It’s funny, but up until recently I assumed there was already a ketchup recipe on my blog. I didn’t discover its absence until I developed Thursday’s recipe (hint: it rhymes with “beet oaf”), when I couldn’t find my recipe online. At first I was confused, and thought the search function of my blog was definitely broken. So…sorry about that, and here you go.

The history of ketchup is pretty awesome. It all started with garum, an ancient fish sauce first used by the Ancient Greeks and later the Romans. It reached Asia some 2,000 years ago via trade routes, and became a staple in many Asian countries, particularly Vietnam (where they later perfected the sauce using anchovies). Vietnamese fish sauce as we know it today entered China about 500 years ago, and the Chinese (particularly those in the Southeast providence of Fujian) spread it around the rest of Asia. The Fujian word for fish sauce? You guessed it, ketchup. In fact, many Asian languages today still use a form of the word “ketchup” to refer to sauces; a common example is the Indonesian word kecap (pronounced “keh-chap”), a catch-all term for fermented sauces.

When Europeans arrived in Asia in the 1600s, they were enamored with fish sauce (they’d long forgotten about garum) and took it back to Europe. Many variations of ketchup existed in Europe for hundreds of years, the most popular being walnut ketchup and mushroom ketchup (the practice of using fish eventually died out). It wasn’t until the 1800s that people started adding tomatoes to the sauce, and H. J. Heinz took it to a new level in 1904 when his company figured out a way to bottle and preserve the sauce using natural ingredients (the mid 1800s were full of horror stories about deadly batches of ketchup made with stuff like boric acid and coal tar). Heinz was also one of the first to add copious amounts of sugar to the sauce.

My recipe still maintains the sweet and sour taste we’ve all come to expect from ketchup, but throws a historical twist in for good measure: a bit of fish sauce.

Homemade, Fermented Ketchup

  • Servings: 2 cups
  • Difficulty: Easy
  • Print

1/3 cup hot water
1/3 cup honey
2 6oz cans tomato paste
2 tbsp whey (the clear liquid at top of yogurt) or sauerkraut juice
1 tbsp apple cider vinegar
1 tbsp fish sauce
1 dash (1/8 tsp) cinnamon
1 dash (1/8 tsp) ground cloves
1 dash (1/8 tsp) garlic powder
1 dash (1/8 tsp) black pepper
1 dash (1/8 tsp) sea salt, more to taste

1. Combine the hot water and honey, stirring until dissolved, then set aside to cool.

2. Combine the honey water and the rest of the ingredients. Add salt to taste.

3. Place in a quart-sized jar, cover, and let set at room temperature until fizzy and delicious. It should take 2-5 days. After the second day, be sure to burp the lid daily to prevent gas buildup. Taste it every day after the second day to see how you like it; once it tastes perfect, throw it in the fridge. It should keep for about 1 month.

** This recipe creates a fairly thick ketchup – to thin it, simply mix in a bit of water to get your desired consistency.

** If you don’t have access to whey or sauerkraut juice, add 1 tbsp water and 1 additional tbsp of apple cider vinegar.

** The slightly fishy taste of this sauce is awesome, but if you’d like to omit the fish sauce altogether, replace it with 1 additional tbsp of apple cider vinegar.

** This ketchup can also be made without fermentation. It’ll be a bit sweeter and won’t have that awesome fizz to it. To make it, simply combine all of the ingredients and simmer on low for about 20 minutes, then cool and bottle. It will only last about 1 week in the fridge.

As a bonus, here is a recipe for ketchup from The Compleat Housewife, first written in 1727 and generally considered the first cookbook published in the United States. Note that this recipe is basically a fermented anchovy dish, with no note of tomatoes at all.

52 thoughts on “Homemade, Fermented Ketchup

  1. Thank you! This looks great and I can’t wait to try it. So far I’ve been pretty disappointed with paleo ketchup recipes.


  2. I just made a fermented ketchup and I was pleasantly surprised at the results, the taste and the fact that we liked it (including the kids!)


    1. Hi Teranne, I would use a pea-sized amount of anchovy paste in lieu of fish sauce. Otherwise, omit the fish sauce and add 1 additional tbsp of apple cider vinegar. Hope that helps!


  3. Thank you so much. I will try this recipe this weekend. Pax, Robbie in San Diego. ps loved the beef burgundy.


  4. Can’t wait to try this, TDM! Personally I’m all-good with the fish sauce for a trial run, but my wife is allergic to all things finfish (thank goodness she can still go to town on shrimp, crawfish, lobster!). Do you have any suggestion for a substitute for that one element in the recipe? I know it’s pretty characterful and probably hard to swap-out. But any suggestions?


  5. I just read about the Sukuma Wiki that you made with Gina at Skinny Taste and had to come over to check out your site. Lovely post on the ketchup. If you’re a history buff, there’s a place in San Diego called the Green Dragon that is part museum and part restaurant/pub. I think you’d like it.


  6. Hi – It’s Michele again – just wanted to let you know that I re-posted to my food blog as well http://www.thesingingtomato.com as this is too fabulous a tomato concoction for it not be shared! I am also sharing on FB and twitter all with references and links back to you and your blog. Thank you so much for continuing to produce such great content! Can’t wait to make mine this weekend!


  7. Can you give more detail on “burping the lid”? I read this instruction in your book as well. Not having fermented foods before, I’m slightly nervous. Thanks.


    1. It just means unscrewing/taking off the lid to let air out. Super quick and easy! Otherwise, you get a lot of pressure (eventually) and there could be an explosion of delicious flavor…all over your counter. But that takes a while and a lot of neglect, so worry not.


  8. I just made 4 jars of this but didn’t use canned paste (I made my own from local tomatoes). It smells great and even though it’s not done fermenting it tastes great too. Can’t wait til it’s done.


  9. Pingback: Probiotic Foods
  10. I think this would be a good way to add protein and other benefits with the fish sauce. But I am trying to replace my 4 year old son’s obsession with ketchup with this. Would it be too fishy for an ketchup addict? Seriously, he puts on a grill cheese sandwich


  11. I made this today, and it tastes great, though I did tweak it a bit. I used half the cinnamon, added 1/8 tsp dry mustard and 1/8 tsp allspice. I also omitted the honey, used homemade Worcestershire instead of fish sauce, soy whey to keep it vegan, added 1 tbsp red wine vinegar, and added water bit by bit until it had the desired consistency. It’s very tasty and I can’t wait until it ferments!


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