Krajab: The Horned Water Chestnut

Krajab 002 Krajab: The Horned Water Chestnut

So, Here I am having a drink with some friends when one, Jaeb, tells me she has a present for me. She excuses herself and 5 minutes later she come back and presents me with what I can only describe as a black bull’s head. I stare at it intently for a few minutes trying to figure out what it is and better yet what I am supposed to do with it when she takes it from me and starts beating it on the table.

Krajab 006 150x150 Krajab: The Horned Water ChestnutAfter more than a few hard whacks the black bull’s head cracks open to reveal a hard white middle which is quickly scooped out and placed in my mouth. I used to be scared when such things happen but anymore I go with the flow and hope it doesn’t kill me. Luckily for me it didn’t kill me and tasted oddly familiar but for the life of me I couldn’t place the taste. The best I could get out of my Thai friends was the name, Krajab.

Once home I did a bit of research and found out that Krajab is a variety of water chestnut known as the horned water chestnut, Paniphal,  horned water Caltrop and Ling Jiao which literally means “bull’s horn” in Chinese. The horned water chestnut can come from two varieties of floating annual aquatic plants that are abundant in South East Asia. They are two species of the genus Trapa: Trapa natans and Trapa bicornis. The latter of the two, Trapa bicornis, is the specie that resembles a black bulls head.

The horned water chestnut grows in slow moving water up to 5 meters deep anchoring itself into the muddy bottom with it’s fine roots that grow off of it’s long submerged stems. It then grows two sets of leaves; fine feather like leaves on the stem and floating leaves with a saw tooth edge that form a rosette on the surface of the water. In early summer a four petaled white flower grows at the center of the floating rosette and is pollinated which leads to the fruit being grown. The seeds of the horned water chestnut can remain viable for up to 12 years but usually germinate within 2 years.

Krajab 007 150x150 Krajab: The Horned Water ChestnutThe plant is spread in 2 ways; the rosette can detach itself from the stem and float to other areas or by the fruit attaching itself to wildlife and being transported away.

The horned water chestnut or caltrop, as it is also called, must be boiled before eating because, as with any water plant, it can be a carrier of fasciolopsiasis . At a certain stage of their life cycle larval flukes leave their water snail hosts and attach themselves to leaves or fruit of water plants forming a small cyst. This only affects the outer skin of the water caltrop but if not boiled the larvae can be transmitted to humans which could result in intestinal flukes, or as I like to call them, your own private dinner date.

You can tell if the horned water chestnuts have been properly boiled as the skin will be patchy and peeling in places. You definitely want to make sure they have been boiled as fasciolopsiasis does not look fun and there are over 10 million cases reported annually in South East Asia.

My friend Jaeb’s parents farm these little gems and sent her a large bag full which she kindly gave to me because she knows I’m always on the lookout for new food finds and this one fit the bill perfectly and literally fell right into my lap.

Krajab 005 Krajab: The Horned Water Chestnut

newsig1 Krajab: The Horned Water Chestnut

11 Responses to Krajab: The Horned Water Chestnut
  1. Martyn
    November 11, 2010 | 1:50 pm

    Strange looking things but if they taste like normal chestnuts then I’d love them. Though the after effects if they’re not prepared properly does put me off a bit. You say they are boiled, do they roast them as well like the more common chestnut fruit.
    Martyn´s last blog ..Thailand’s Amazing and Dangerous RoadsMy ComLuv Profile

  2. Talen
    November 11, 2010 | 2:24 pm

    Martyn, I don’t think they roast them but the boiling is more to kill off any possible larvae on the skin.

    The taste is definitely like that of a regular chestnut if not a little bit less than.

    The longer they sit after boiled the fruit seems to be harder too.

  3. Paul Garrigan
    November 11, 2010 | 3:31 pm

    Hi Tim, I’ve seen these before but had had no idea what they tasted like. I remember seeing a sign advertising them and I thought it was a type of bat. They certainly do look strange – not very appetizing looking.
    Paul Garrigan´s last blog ..The Magic of Thailand – A Day with the Spirit DoctorMy ComLuv Profile

    • Talen
      November 11, 2010 | 7:10 pm

      Paul, they definitely don’t look appetizing but they are pretty good.

  4. Martyn
    November 12, 2010 | 2:47 am

    Talen if they taste like the real thing, I’ll grab a bag if I ever see them on a stall. I love chestnuts.
    Martyn´s last blog ..Thailand’s Amazing and Dangerous RoadsMy ComLuv Profile

  5. Snap
    November 12, 2010 | 11:55 am

    Talen, I tried these in China. My Chinese friend said they were ‘fruit’, so I gave them a go. I graciously tried one and offered her the rest of the bag. Not much of a taste really, just starchy. Perhaps they would have been more appetizing had they been boiled in salty water?

    I’ll definitely look out for them here.

    • Talen
      November 12, 2010 | 12:03 pm

      Snap, I don’t think you will find them much different here in Thailand. While a few I have eaten seemed to have more taste than the other for the most part they are just as you described. They incredibly good in salads though.

  6. Catherine
    November 12, 2010 | 9:51 pm

    Talen, I’ve seen the weird chestnuts but didn’t try them out. I only bought a few because they were so odd looking.

    Strange stuff from the shops go into my fridge, fall to the bottom of the drawer, and then get turfed out when showing signs of decay.

    Shame on me.
    Catherine´s last blog ..Thais Learning Thai- Kaewmala from Thai Talk- Part 1My ComLuv Profile

    • Talen
      November 13, 2010 | 2:51 pm

      Cat, oddly enough my chestnuts didn’t last long. I had a few and the rest got sort of a white haze to em so I chucked the rest.

      P.s. I am in your neck of the woods tonight …
      Talen´s last blog ..Krajab- The Horned Water ChestnutMy ComLuv Profile

  7. ChuckWow
    November 13, 2010 | 2:06 pm

    I always see these signs alongside the highway between Nakhon Sawan and Bangkok that look like the silhouette of a bulls head.

    I thought they were selling some kind of BBQ but wasn’t sure so I asked my wife what it was – she tried her best to explain but took one look at my face and just said “I show you”.

    She bought a bag full and peeled one for me. I always go slow when trying unfamiliar plant life in case I have an allergic reaction or it turns out to have some unexpected psychotropic properties.

    I ate the first one and waited a while. It didn’t seem to have any adverse effects so I polished off the entire bag.

    I think these are quite tasty once you get past the outer shell bit I don’t think they are worth the effort.

    My wife doesn’t seem too interested in them so I have only tried them once.

    At least now I know what all those damn signs are for.

    • Talen
      November 13, 2010 | 2:57 pm

      Chuck, it’s funny you mentioned the bull head signs…I have seen them as well but never knew what they were for. I assumed it was something to do with water buffalo.

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