Introduction: Century Eggs

About: Build.Share.Destroy.Repeat. Follow me and try a few of my projects for yourself!

Whether you call them century eggs, hundred-year eggs, millennium eggs or whatever, these outlandish ova are a Chinese delicacy dating back centuries to the Ming Dynasty. The boastful name suggests these eggs take forever to make, this is a misnomer. Century eggs take about 4-5 weeks to make, a few minutes to work up the courage to open, and a few seconds to eat.

Traditionally century eggs were made by preserving chicken or duck eggs in a mixture of salt, lime and ash, then wrapping in rice husks for several weeks. During this time the pH of the egg raises transforming the egg, the chemical process breaks down some of the proteins and fats into smaller, more complex flavours. After curing the yolk of the egg turns a dark green and has a creamy consistency, while the white turns amber and is gelatinous. 

I chose a more modern method to achieve the same results: a salt and lye pickling solution, and encasing in modelling clay. After about a month my eggs were ready, and I'm happy to say they turned out perfectly!

Want to make your own? Of course you do! 
Enough talk, let's make some eggs!

Step 1: Supplies + Materials

  • 100% lye/caustic soda (NaOH - sodium hydroxide)*
  • salt (NaCl - sodium cloride)
  • chicken egg (duck or quail egg)

* Technically lye is a corrosive, not poison. Though, it' can be labelled as either. It's incredibly dangerous to handle and can cause severe burns with contact to skin, there's also an inhalation risk. Use gloves and a respirator.
There's plenty of other foods that are made/prepared with lye, but use caution and common sense.
Always use pure, 100% lye (sodium hydroxide).

Step 2: Prepare Pickling Solution

Start by making the pickling solution, here's the basic breakdown:
  • 1L  - Water
  • 42g - Sodium hydroxide(NaOH)   (lye)
  • 72g - Sodium chloride(NaCl)   (salt)
On a scale weigh out the lye and salt. Over low heat dissolve the salt and lye completely in water. Bring the solution to a boil and allow it to cool down before use.

Place raw eggs into glass jar and pour the cooled pickling solution over eggs. Ensure all eggs are completely submerged. 

Step 3: Store

I wrote the date of submerging these eggs on my label, as well as the expected dates for encasing in clay, and eventual consumption. Label jar and store in a safe place, like the corner of your desk, so all your coworkers can gawk in disgust (or silent admiration). I also added a warning so my coworkers wouldn't mess with the jar while the eggs were pickling.

Leave eggs at 15-20°C (60-70°F) for about 10 days. Keep an eye on them to ensure they don't pop up above the solution and stay submerged.

Step 4: Remove From Brine

After about 10 days it's time to remove the eggs. Carefully pour out brine and pick out eggs, rinse with water then towel dry. The shells should still be hard.

You should be able to see some discolouration through the shells. 

Step 5: Encase

Traditionally century eggs were rolled in mud then wrapped in rice husks and buried for a few more weeks. In this modern version I simply wrapped the eggs in several layers of clear plastic wrap then encased in modeling clay. This inhibits oxygen from reaching the eggs while they cure.

Be careful when encasing in clay as not to break the eggs. After wrapping I put all the eggs into a resealable bag and left for another 2 weeks. 

Step 6: Crack Open

After about a month from the when the eggs were first put into the brine solution it's time to open them up. Carefully remove the clay encasement and the plastic wrap, then tap the egg to break the shell and gently peel away. The eggs should be completely transformed!

The whites of the eggs will now be a jelly-like translucent amber colour and the yolks a very dark green and with a texture much like a hard boiled egg. Take a look at picture 2 in this step to see the different consistency between the yolk and white in my egg-xperiment.

Step 7: Serve!

Century eggs are typically served mashed up in soupy rice. I made a steamy bowl and served it to my friends.

The taste was...interesting. The appearance is deceiving and almost put me off eating it altogether, but once I ate some it wasn't that bad. It tasted kind of like a hard boiled egg, only with a more complex flavour and a slightly mineral/metallic taste. I'm happy I tried this and think I would probably eat it again. You know, sometime later (much, much later).

Did you make your own version of century eggs? Post a picture in the comments below.

Happy making :)