“Pidan” 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.
- Clay from ant hills is preferred. Dry and pulverized the ant hill.
- Add salt, mix and moisten with water to make a thick paste.
- Coat a fresh or one-or two-day old egg with a 1/4 inch thick layer of the mixture.
- Layer the container, preferably an earthen jar, with the paste of about 1/2 inch thick and then arrange the mud-coated eggs up to almost an inch to the brim of the container.
- Spread 1/2 inch of the paste evenly on top and sprinkle salt on it and then cover.
- Place the salted eggs in a cold, dry place. It takes 30 days to cure chicken eggs and 45 days to cure duck eggs.
- 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
- 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.
- 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.
- Submerge the eggs in the saline solution, and store at 15 to 20°C for about 10 days.
- Pick out the pickled eggs and rinse them. Then allow them to dry naturally.
- 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.
- 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.
sources: sharedhowtos.com, agnet.org, sg.answers.yahoo.com