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Bat nuts roasting on an open fire (aka devil pod, bull's head, bull nut, buffalo nut, water caltrop, trapa natans, Ling Jiao)

rworange Oct 7, 2006 08:04 PM

It must be the Halloween spirit getting to me. I bought a bag of these bat-like, scary, evil-looking nuts at the Berkeley Bowl..

That link says “roasted or boiled like true chestnuts ... They are delicious sauteed with rice and vegetables ... they contain toxins and should not be eaten raw. Seeds of some species are preserved in honey and sugar, candied, or ground into flour for making bread. In Italy Trapa natans is the main ingredient of a famous risotto.”

So have you tried them and what is your preferred method of eating them ... like anyone’s got a box of bat nut recipes ... there’s a cookbook waiting to happen. Didn’t turn up that risotto recipe.

I promise to report back on the taste, supposedly starchy like potatoes or peanuts. I read they need to be boiled for 25 minutes. I’m assuming that used in recipes like sauteed with veggies, they need to be boiled first.

I guess they roast these on street corners in Taiwan like chestnuts.

It’s true that each side has a ‘face’ on it and each is a different looking face. Actually they are starting to creep me out, so I want to cook them soon.

More about bat nuts:

Growing your own using the bat nuts from the market:

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  1. Pei Oct 7, 2006 09:58 PM

    I love those! They are sort of a cross between a chestnut and a peanut. I just boil them in salted water with a few pieces of star anise, and break them open like roasted chestnuts. They're hard to overcook, so I just let them simmer for half an hour or more. They're done when they're soft all the way through.

    5 Replies
    1. re: Pei
      rworange Oct 7, 2006 10:12 PM

      Cool. Thanks. I'll add some star anise.

      1. re: rworange
        Pat Hammond Oct 8, 2006 08:17 PM

        I thought the name "caltrop" sounded familar! I posted about finding them in an Asian market over two years ago. I wanted to try roasting some, but never found them again. In my old thread I loved reading that Ruth Lafler carried one around in her pocket as a conversation piece! Maybe now is the season for them, and I'll spot them again.


        1. re: Pat Hammond
          rworange Oct 9, 2006 03:10 AM

          Thanks for the old link. That's why I put all the names in the title because I figured is someone didn't recognize one name, they'd recognize another.

          Thought it was cool that the calthrop name came from a medievil weapon and a weapon used during WW1 to puncture tires.

          The Chowhound link didn't appear in Google, and with all those names, I wasn't sure what to use to try a Chowhound search. So I appreciate the old link.

          Josh did an excellent job of describing them and, uh, did he ever post again after that?

          I'm not sure how poisonous they actually are raw. There were a few people who said they ate them raw and they tasted 'fresh' whatever that means. I think I'd rather be safe and cook them though.

          1. re: Pat Hammond
            JMF Oct 9, 2006 01:27 PM

            Pat, they have them at Kam Sen market in the old White Plains Mall as of last week.

            1. re: JMF
              Pat Hammond Oct 9, 2006 10:17 PM

              That's where I originally saw them! It must be caltrop season again. I noticed that my post about them was in mid-September. Thanks!

      2. FoodFuser Oct 7, 2006 11:41 PM

        Here's the risotto. This was a real bear to find, and it exists only in Italian with a gnarly Google translation. If you have an Italian friend or restaurant person they can translate from the real Italian.

        It seems pretty straightforward: equal amounts of nut meat and rice, with a heavy suate for the nuts. These bat nuts contain tannins, and most recipes out there indeed boil them. They've GOT to be heated for a long time.

        Caveat: Some confusion within recipes exist between the Eleocharis water chestnut and this the Trapa nutans (synonym Trapa bicornis). Eleocharis is free from the dangerous tannins.

        There may be a real commercial future for these things: they are an extremely aggressive invader species on the mid atlantic coast, and one way to control the population is to find a market to suck up the supply.

        ( "castagna d'acqua" risotto ) in google will yield this page:


        then scroll down to "Risotto con castagne d’acqua".

        Pei's star anise boil sounds good. After you try that, this risotto would be interesting to see the interplay between the 2 starches.

        I'll check for these in my market. I've dug them before when I lived near the coast, and just did the standard "boil, extract from shell, then butter", which was excellent.

        Looking forward to your report.

        1 Reply
        1. re: FoodFuser
          rworange Oct 8, 2006 02:36 AM

          Again, thanks. The thing I love about Chowhound. You can ask a question and get an answer no matter how obsure. There were really no recipes out there for these things. I'm starting with the star anise first and then working my way up depending on how I like them. When I saw them I figured I'd give them a try and google and if that failed ... ask here.

        2. vicki_vale Oct 8, 2006 08:00 PM

          Those things are cool. I've only ever eaten them boiled, and I recall they were a challenge to peel. They look interesting when they're dried, too.

          1 Reply
          1. re: vicki_vale
            rworange Oct 9, 2006 03:13 AM

            The whole unshelled nut dried? Or the inside? They have such a hard shell, I imagine unpealed they would last forever.

          2. FoodFuser Oct 9, 2006 11:01 AM

            As with any good starch, the plot thickens.

            Perhaps some indian/bengali cooks could chime in here.

            "Singhara" is the Hindi name for Trapa; "Paniphal" is the Benagali. It seems to be used widely as "singhara atta", a flour made from the mature nut. When immature, the nut is eaten raw. I'm really confused about the whole raw/cooked thing.

            How is it used, as nutmeat, in curries, etc?

            Link to commercial cultication, with 4 imbedded pics:


            Link to synonomy, for both common and scientific names, representing the multicultural usage of this food. Also representing the confusion among taxonomists; some think it is simply one polymorphic species:


            1. rworange Oct 10, 2006 09:42 PM

              The results:

              Boiling with star anise was best. Roasting was ... exciting.

              First I boiled two for the natural flavor. They still needed a nutcracker to open and I needed a nut pick to get the flesh out.

              They sort of remined me of a Brazil nut but not as oily, a little more starchy/potato tasting and crumbly. There's a faint sweetness to them.

              Once I went out and bought some star anise ... and there's something wrong with the picture if you have bat nuts in the house but no star anise ... I boiled two more of those. The house sure did smell nice ... briefly.

              I figured I'd throw the last four in the oven and roast them ... I was kind of hooked on the thought that someone said that the bat nuts roasted on street corners in Taiwan "smelled like Autumn". How lovely, I thought.

              Set the timer for 30 minutes ... bat nuts boiling in star anise on top of the stove ... bat nuts roasting in oven set on medium heat.

              After a while, a smell wafted into the office ... that of smoke. The bat nuts were glowing red like charcoal bricks. Given their evil looking appearance raw, you can imagine how impressive these were the little wing tips flaming and the faces with glowing red eyes.

              Not just that, when I opened the oven they threw off showers of sparks.

              So I would say to anyone trying to roast them ... low heat and keep an eye on them.

              I guess what has been most annoying was when Roberto walked in the door, smelled the smoke and asked "Honey, have you been cooking?"

              As to the star anise nuts, the flavor didn't really permeate the thick shells, but it did accentuate the sweetness of the nut. I'd say at this point, boiled with star anise is the way to go.

              They were really crumbly so I tossed them on a salad. They looked like coarsly crumbled cheese.

              And that was lunch today ... mixed organic lettuce, baby kiwis and bat nuts dressed with a lemon garlic vinagrette I had left from a Puerto Rican place. It was very good.

              If I had my own restaurant, it might not have the best food, but it wouldn't have the same stuff you'd see on every other menu in town ... no pork bellies or hucklberries. Bat nuts and baby kiwis.

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