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    Home » Condiments

    Black Walnut Ketchup / Catsup

    Published: Apr 12, 2021 Modified: Feb 7, 2023 Author: Alan Bergo

    Jump to Recipe

    Walnut ketchup is an old sauce from a time when the word ketchup or catsup referred to anything but a sauce made from tomatoes. It tastes a bit like steak sauce, but it's made from unripe, green walnuts instead of a mix of spices. 

    a bottle of walnut ketchup with green walnuts
    Walnut ketchup is an old-time sauce that deserves to be remembered. It tastes a bit like steak sauce.

    Originally a British recipe, the sauce is still made and sold in bottles to this day, along with other sauces of the same name (mushroom ketchup, for example). Interestingly, I see more recipes for walnut ketchup in books detailing cooking from the 19th century in the United States.

    I'd wager that the sauce may have been more popular there that it was originally in Britain, but that's just speculation. One thing that's not up for debate, is that the sauce traveled to the United States through British immigrants. 

    Green walnuts or young black walnuts for ketchup
    You're looking for green walnuts. When they're this big, I make sure to come back in a week. You want them about the size of a small ping pong ball as pictured in the images at the top of this post. 

    Given the thrifty nature of the time, It makes sense that the sauce would catch on in North America, as black walnut trees are widespread, and, generally speaking, most people in the United States can probably get access to black walnut trees with a short drive. 

    Traditional Methods 

    Like a lot of traditional recipes, there seems to be as many ways to make ketchup from walnuts as there are stars in the sky. Good Housekeeping in Old Virginia, one of my favorite 19th century cookbooks, lists at least 3 or 4, with all of them being very different. Here's some examples. 

    Black walnut ketchup and bay sauce (3)

    Looking at the recipes you can see there's some big differences in the way the sauce was made. I've made variations of all of the recipes listed above. The most difficult was by far the third recipe that calls for "bruising the walnuts" and straining off their "liquor".

    Let me tell you, there's not a lot of juice in a black walnut, and bruising/crushing them hard enough to remove any liquid at all turns into a black mess that will stain your hands and anything around it for weeks to come.

    All of the traditional recipes I've recreated yield a sauce that's thin, and similar to Worcestershire. If that sounds good to you (it is good) make a note to try them.

    The recipe I share in this post is thicker, making it easier to use as a sauce for most people. That being said, using some traditional walnut ketchup in places where you'd typically add Worcestershire works well. 

    Traditional black walnut ketchup
    A traditional black walnut ketchup is thin and tastes like Worcestershire to me.

    Making a modern recipe 

    The key with this for me was all about finding how to control the extreme tannins of black walnuts, while coaxing out their natural citrus flavor and ending up with a finished product that was jet-black.

    Some recipes recommend repeated soaking, and draining (leaching) but this made a final product that lacked color and came out grey-off-green: not attractive.

    The soaking leaches out tannins, and is useful, but repeated soaking and draining also leached out the natural citrus flavor of the walnuts I wanted to capture. So, after about 5-6 batches, 500 or so passive hours of work, and a good 120 walnuts, I developed a hybrid method, and it scores high on every note.

    Leaching or soaking green walnuts (4)
    Before being made into my ketchup, the walnut are leached in water. Older recipes skip this step.

    In my version the walnuts are soaked, but the water is only discarded at the end of 7 days, so that the citrus aroma continues to penetrate the walnuts as they naturally ferment in the water, but enough soaking liquid is discarded to noticeably soften the tannins we associate so strongly with black walnuts in things like vin de noix and nocino.

    To fix the grey-green color, after leaching, the walnuts are left out for 24 hours, which oxidizes and blackens them, which in turn lends the jet hue to the finished sauce.

    The end result is a condiment that tastes a bit like black walnuts smell, although the aroma will fade into it’s own thing over time.

    The journey to victory, as well as the epic fruit fly battle of emanating from multiple gallon jars of fermenting walnuts, during the peak of summer, was one of the more difficult projects I’ve done.

    How to use 

    Once you've made your sauce, you might wonder what the best ways to use it are. I like to tell people to think of it like steak sauce, but not just for steak. It's a tart, spiced, aromatic condiment you can use in small amounts to spice things up-and you don't have to use it all by itself, especially if you find the flavor a little strong for you. Here's a few ideas. 

    • Dash some walnut ketchup on top of fried potatoes. I have one friend who even puts it on his potato chips. 
    • It's a good sauce for proteins, especially beef and pork. Fish can work too, but I like to warm the sauce up a bit and whisk in some butter to smooth it out. 
    • Dashed on grilled or roasted vegetables. 
    a bottle of walnut ketchup with green walnuts
    a bottle of walnut ketchup with green walnuts
    Print Recipe Pin Recipe
    5 from 5 votes

    Black Walnut Ketchup / Catsup

    An old-time sauce made from green, unripe walnuts. It tastes a bit like steak sauce. Yield: about 4 cups
    Prep Time15 minutes mins
    Cook Time30 minutes mins
    Soaking time7 days d
    Total Time7 days d 45 minutes mins
    Course: Condiment
    Cuisine: American, English
    Keyword: Green Black Walnuts, walnut ketchup
    Servings: 64 Servings
    Calories: 214kcal
    Author: Alan Bergo

    Equipment

    • 1 Blender
    • 1 Non-reactive container for fermenting like an old glass pickle jar

    Ingredients

    • 1 lb young black walnuts or butternuts
    • 3 cups apple cider vinegar
    • 1 cup red wine
    • 60 grams 4.5 Tablespoons kosher salt
    • 1 oz ¼ cup chopped fresh horseradish
    • 1 medium onion (1 cup chopped)
    • 1 large clove of garlic, crushed
    • 1 oz ¼ cup chopped fresh ginger
    • ½ tablespoon each: whole allspice and cloves
    • 1 Tablespoon black peppercorns
    • 2 oz anchovies in oil, rinsed optional but recommended
    • ¼ teaspoon xanthum gum

    Instructions

    • Soak the walnuts in water for 7 days, without changing the water. The walnuts will ferment naturally. After 7 days, drain the walnuts, crack them, and spread out on a tray until they oxidize and turn black, about 24 hours.
    • Toast the peppercorns, allspice and cloves in a pan, then grind to a fine powder.
    • Chop the walnuts coarsely, then transfer to a saucepan with the remaining ingredients except the xanthum gum, bring to a simmer and cook for 15 minutes, covered, until the onions are soft. Transfer the mixture to a highspeed blender, puree, strain, then combine with the xanthum gum and puree again to thicken.
    • Store the ketchup in a glass jar in the refrigerator. For long term storage, hot pack by pour boiling hot ketchup into a mason jar, screwing on the lid, and turning upside down, allowing to cool and seal. Alternately the ketchup can be canned in mason jars using a water bath.

    Notes

    How to use 

    Black walnut ketchup is a sort of all-purpose condiment. Try putting it in a bottle you can shake from, and trying it on things like roasted potatoes, grilled meat and fish, and roasted vegetables. Some people use it like Worcestershire sauce. 

    Nutrition

    Serving: 1Tablespoon | Calories: 214kcal | Carbohydrates: 10g | Protein: 6g | Fat: 16g | Saturated Fat: 2g | Polyunsaturated Fat: 3g | Monounsaturated Fat: 10g | Cholesterol: 2mg | Sodium: 1569mg | Potassium: 275mg | Fiber: 3g | Sugar: 1g | Vitamin A: 11IU | Vitamin C: 1mg | Calcium: 38mg | Iron: 2mg

    More

    Cooking with Green Walnuts 

    Related 

    Guide to Black Walnuts 

    « Sopa de Ortiga from Extramadura
    Green Stinging Nettle Crepes »

    Reader Interactions

    Comments

    1. PJ Ray

      July 27, 2024 at 9:48 am

      I'm currently working on this recipe, using green walnuts from a European walnut - instead of the black walnuts you're showing.

      However, my green walnuts look kind of funky after the 7 days in water. I took some images: https://i.imgur.com/n1GPIwP.jpeg https://i.imgur.com/rIxc1eC.jpeg https://i.imgur.com/bJmv2OO.jpeg

      Does this look correct? They were slowly bubbling over the week (I left my jar slightly open, so it wouldn't have problems with pressure), and there was this odd layer on the surface of the water when I opened them.

      They don't smell odd or anything, but some of them turned a bit softer and more brown. I currently have them sitting overnight to darken.

      Reply
    2. John Paul

      July 04, 2024 at 2:39 pm

      Sadly, this recipe did not turn out well for me. The vinegar smell/burn completely over-powered all of the other flavors. I went over the directions and ingredients, and the only thing I didn't follow exactly was with the anchovies. All of my local grocers were out of the cans of fillets (what is going on in my city?) and so I had to settle for anchovy paste. The conversion was 3 Tbsp (a whole tube) equals 2 oz of anchovies. I did see that there was vinegar in the ingredients list, but I think it would be odd to have such a small amount make such a big impact.

      Is 3 cups of apple cider vinegar correct? I checked out some other tomato ketchup recipes and most use between 1/2 and 3/4 cup vinegar for 3 cups of sauce.

      Reply
      • Alan Bergo

        July 05, 2024 at 10:42 am

        John, this sauce is nothing like tomato ketchup, think more along the lines of steak sauce, but looser and more potent. Ketsiap is a Vietnamese word that American ketchup is derived from and the product is similar to fish sauce--nothing even close to tomato ketchup. You'd want to compare my recipe with other recipes for walnut ketchup if you want some baseline ratios to compare. The sauce also improves over time as it sits, as does everything made from green walnuts. If you haven't made strong, potent sauces like this, the flavor, especially at first before it has time to mellow and soften over time, is powerful. Forget about the jar for a month or so, then try dashing it on roasted potatoes or vegetables or other mild tasting things.

        Reply
        • John Paul

          July 05, 2024 at 6:31 pm

          Oh, that's great to know, thanks. I'll take another taste in a month or two.

          Reply
    3. John Paul

      June 30, 2024 at 2:36 pm

      When it comes time to spread the walnuts out on a tray to oxidize, should they be left out at room temperature or refrigerated?

      Reply
      • Alan Bergo

        June 30, 2024 at 2:42 pm

        Room temp is all I’ve ever done but you could put them in the fridge too.

        Reply
    4. Richard Stevens

      March 16, 2024 at 3:08 pm

      5 stars
      I made this and substituted miso for anchovies. It was amazing! Best 'steak sauce' you will ever eat.

      Reply
      • Alan Bergo

        March 19, 2024 at 1:24 pm

        Hey Richard, Nice move substituting miso for anchovies, great hack there.

        Reply
    5. Bill Fowler

      December 01, 2023 at 2:28 pm

      Are you using the entire walnut: hull shells and whatever little nut may be in a immature walnut?

      Reply
      • Alan Bergo

        December 02, 2023 at 5:26 pm

        Yes, please refer to my article on green walnuts. The entire thing, green hull and all is used. This is a very traditional recipe.

        Reply
    6. K-A

      August 13, 2023 at 8:16 am

      5 stars
      I tried this recipe and I'm not sure I was successful. When you say "puree, then strain" can you expand on that? How much liquid to strain? Do I throw out the liquid?

      Reply
      • Alan Bergo

        August 27, 2023 at 4:33 pm

        You puree it in a blender, then strain it. The solids are discarded, the liquid is the ketchup.

        Reply
      • Ian Campbell

        June 29, 2024 at 12:01 am

        5 stars
        Excellent tasting sauce! The only modification I made was that when weighing the salt on my scale, 60 grams translated to about 3 tablespoons, so I went with that amount instead of the 4.5. Sadly I haven’t had anything to put it on yet. I have had it stored in my refrigerator for a few days but I think I want to jar most of it. Can I bring it to a boil again and then immediately pour it into hot, sterilized jars and invert? Do I have to boil it again for a certain duration? Or is reboiling it now a bad idea since the xanthum gum is already in the mixture?

        Also, is there any reason that the solids, once strained out, couldn’t be dehydrated and grinder for a spice- similar to what is done with the solids from mushroom catsup? I did this but haven’t tried it yet as a spice!

        Reply
        • Alan Bergo

          June 30, 2024 at 2:50 pm

          Hey glad you liked it. Drying the solids isn’t something I would do. Not a lot of flavor in the leftovers, compared to seasonings I dry like ramp salt. I discard the solids and thank them for their service.

          Reply
    7. Taija

      May 08, 2022 at 11:35 pm

      Hi Alon,

      I am confused, in Switzerland we got walnut, I am just aware from one species…
      You are talking about green and black walnut.
      Is this the same tree? If so I understand and waiting for Saint John’s Eve.
      For us the traditionell day to harvest “ green walnut” .
      Greetings Taija

      Reply
      • Alan Bergo

        May 09, 2022 at 6:48 am

        Taija,
        The only walnuts I’m speaking about here are Juglans nigra. When they’re green, they’re referred to as green walnuts, or unripe walnuts. Technically you could also call them green black walnuts. Does that make sense?

        Reply
      • Katie B

        June 04, 2023 at 2:03 am

        I would like to try canning this, using hot water method.
        I am wondering if you know how long it needs to be in the water bath for.
        I have a tiny fridge and a huge walnut tree, plus many in my area (thank you squirrels) and want to make a large batch to share. I think I need to preserve it in jars. Thank you for any help on this, and for sharing your recipe.

        Reply
        • Alan Bergo

          June 04, 2023 at 3:39 pm

          It needs to be in the water bath for whatever the recommended time is for pickling the size of jars you're using.

          Reply
    5 from 5 votes (2 ratings without comment)

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