Pidan (Chinese) or alkalized egg is a traditional Chinese delicacy made from either duck or chicken eggs. These are often called thousand-year or century-old eggs, even though the preserving process lasts only about 30 days. Eggs are soaked in a saline solution (for 15 days in summer or 20 days in winter). No boiling is needed. To check eggs for cracks, test according to the sound of eggs knocked gently against each other. Good eggs give off a higher pitch. Ammonia (NH3) is sometimes emitted, which has a pungent smell.

Procedures:

1. Preparing the pickling solution:

  • Water 1L
  • Sodium chloride(NaCl) 72g
  • Sodium hydroxide(NaOH) 42g

Dissolve the NaCl and NaOH completely in water. Bring the solution to a boil and allow it to cool down before use.

2. Submerge the eggs in the saline solution, and store at 15 to 20°C for about 10 days.

3. Pick out the pickled eggs and rinse them. Then allow them to dry naturally.

4. Coat with PVA (polyvinyl acetate) or some other non-ventilated packaging material. An alternative is to add red soil to the saline solution after the pickled eggs are removed. Coat the eggs with the mud, and roll them in rice husk. Age for about 2 weeks.

5. Crack the eggs lightly and remove the shell. The white of the egg will have a grayish, translucent color, and a gelatinous texture. The yolk, when sliced, will be a grayish-green color.

Updated: Oct. 27, 2009

Another Method taken from Yahoo Answers:

If you need a recipe to make them, you can make them as follows:

  • 2 c Tea, very strong black
  • 1/3 c Salt
  • 2 c Ashes of pine wood
  • 2 c Ashes of charcoal
  • 2 c Fireplace ashes
  • 1 c Lime
  • 12 Duck egg, fresh

Procedure

  • Combine tea, salt, ashes and lime.
  • Using about 1/2 cup per egg, thickly coat each egg completely with this clay-like mixture.
  • Line a large crock with garden soil and carefully lay coated eggs on top.
  • Cover with more soil and place crock in a cool dark place. Allow to cure for 100 days.
  • To remove coating, scrape eggs and rinse under running water to clean thoroughly.
  • Crack lightly and remove shells. The white of the egg will appear a grayish, translucent color and have a gelatinous texture.
  • The yolk, when sliced, will be a grayish-green color.

source

source: www.agnet.org

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18 Responses
  1. dak says:

    I bought on ebay.

  2. Jess says:

    Where can we buy the chemicals for making century eggs?

    • Leo says:

      @Jess, inquire from Chemag Foods, (2) 687-9077, or spices&foodmix house (02) 411-1349, 742-0826

      • ronald says:

        CHEMAG has no food grade sodium hydroxide.
        spices&foodmix didnt answer my call.

        and really, food grade sodium hydroxide is very hard to find. most of the stores dont have the food grade. they only have “technical grade” and the “analytical grade”. IS IT SAFE TO USE EITHER OF THE TWO? WHICH IS SAFER?

        • ronald says:

          CHEMAG has no food grade sodium hydroxide.
          spices&foodmix didnt answer my call.

          and really, food grade sodium hydroxide is very hard to find. most of the stores dont have the food grade. they only have “technical grade” and the “analytical grade”. IS IT SAFE TO USE EITHER OF THE TWO? WHICH IS SAFER?

          @source: can you introduce to us where to buy food grade sodium hydroxide? if none, what alternate chemical can we use where in it is safe for us to use.

          i tried the technical grade sodium hydroxide and followed the process. it was a success, century egg it is. but i called the store where i bought the sodium hydroxide, they told me they dont recommend to use the technical grade.

          any remedies?

        • Leo says:

          @ronald, i found another method of making century egg, please refer to updated post above.

  3. Dirk says:

    Listern i like to make century eggs here in South Africa, can any one please help me with a recipe that works and make egss taste great.

    Thank you

  4. romeocharlie says:

    has anyone out there tested this recipe? kinopya ito verbatim from a taiwan agriculture website, isn’t 4% caustic soda a bit much?

  5. limraul says:

    Where can I buy food grade Sodium Hydroxide or Caustic Soda? Can somebody please answer this?

    • rizza says:

      hi, do you know where to buy caustic soda? if so, could you tell me? my niece needs it for her thesis? thanks in advance.

  6. debbe says:

    Truly a fascinating process. You better believe I will try it. *g*

  7. baday says:

    ang ganda ng mga steps nyo

  8. anonymous says:

    in any hardware store near to you…….hehehehehehehehe

  9. Handy1 says:

    I bought some from the grocery store, but after having read this, I’m trying it.

    Since this is only experimental, I’m doing everything in 1/10 scale with only one egg. I’ll keep you guys updated. I might taste it after it’s done, but I’m sure as hell going to spit it out. For God’s sake, I’m using technical/industrial grade lye. Who knows what sorts of impurity is in there. I think you ought to use pharmaceutical or food grade lye if you plan on eating what you make.

  10. frankie says:

    I thought you were supposed to use lime? or is that just an option?

  11. sirchlennaj says:

    wet market;

  12. Leo says:

    melchor tiu Says: 5/10/2006 06:11:00 PM

    how many eggs will i soak to the saline solution?

    Eu-Leh Says: 5/10/2006 11:28:00 PM

    enough to be at least below the level of saline solution.

    Anonymous Says: 10/06/2006 10:58:00 AM

    What is the shelf life of the century egg?I really need the answer for my chem. project!!??

    Anonymous Says: 1/11/2007 01:01:00 AM

    what kind of mud? and where do you get it? thanks! :)

    Eu-Leh Says: 1/16/2007 12:06:00 PM

    the clay mud from ricefields will be a good material. if you are in bulacan, nueva ecija or batangas area, you don’t have any problem getting the mud.

    Anonymous Says: 6/13/2007 04:09:00 AM

    Forgive my ignorance Sodium Chloride, is this the table salt or rock salt? Where could I buy Sodium hydroxide? What is the common name of sodium hydroxide?

    Eu-Leh Says: 6/13/2007 09:50:00 AM

    Rock salt should be used. Sodium hydroxide is also known as lye or caustic soda.

    Anonymous Says: 6/14/2007 01:16:00 PM

    Where could I buy this lye or caustic soda?

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