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What is a Century Egg?

A Century Egg is a culinary marvel from China, where duck, chicken, or quail eggs undergo a preservation process that transforms them into a jelly-like delicacy with complex flavors. This traditional treat, also known as a thousand-year egg, is a testament to the ingenuity of ancient food preservation. Ever wondered how it's made and what it tastes like? Join us to uncover the secrets of this unique dish.
J.L. Drede
J.L. Drede

A century egg is a duck egg that has been preserved in a mixture of ash, lime, salt, clay and rice for weeks or even months. Also called a thousand-year egg or millennium egg, it is considered a delicacy in China, where the recipe originated thousands of years ago. They are known for an exceptionally strong taste and odor, which is reminiscent of sulfur or ammonia.

After the preservation process is complete, the shell of the egg is speckled, giving it an aged appearance that may have given it is name. When the egg is cracked open more drastic change are become apparent. The white has changed from clear to a dark brown color and is gelatinous in texture. The most notable change though is the in egg yolk. Instead of a bright yellow, it is dark-green/black and has the texture of thick cream or yogurt. Most of the strong smell and taste of the century egg comes from the yolk, which absorbs more of the special fermenting solution during the preservation process.

Century eggs are considered a delicacy in China.
Century eggs are considered a delicacy in China.

Some compare the hundred-year eggs to smelly cheeses in both taste and selective appeal. Others describe the taste as resembling a traditional duck egg, just much stronger with an aftertaste that resembles vinegar or ammonia. In America, the egg's off-putting appearance and strong taste made them a popular food of choice for shock game shows that forced contestants to eat gross foods. In China, however they are considered a fine delicacy and are often served as appetizers at weddings and other parties. These eggs may be mixed together with traditional eggs, ground up and used as a topping, or on slices like an orange. They are also found in soups, porridge, omelets and just about any other dish where you might find typical eggs.

The century egg is just one example of specially prepared eggs in Chinese cuisine. The Chinese make many other dishes that involve soaking eggs in special mixtures, including the soy egg and tea egg. The century egg though is the only one that is considered a delicacy, the others are commonly sold as snacks by street vendors. This may have to do with the complex preparation that goes in the creation of the hundred-year egg, or just because its incredibly pungent taste and smell is off-putting for some.

Century eggs remain popular in China and other Asian countries, although the preparation process has changed with new technology. While some still prepare the eggs in the traditional method, many companies who sell the eggs pre-packaged soak them in salt brine, sodium carbonate and calcium hydroxide. Using this method, a century egg can be prepared in less than two weeks, as opposed to a month or more. Some egg makers have resorted to using lead oxide to speed up this process, leading to concerns of lead poisoning and other health problems.

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Discussion Comments


@KoiwiGal - If you are buying the eggs in your own country, they would be subject to your laws so they should be safe enough.

I don't see what the big deal is, personally. People forget that almost every culture have some way of preserving eggs. Pickled eggs are very common in the USA and Europe, for example. They aren't the most pleasant of meals, but they are safe enough.


@pastanaga - Ironically, you'd be safer with the urine eggs, since they are boiled and that would probably take care of any potential health issues.

The century eggs have been made with heavy metals in the recipe in the past and could actually be quite harmful to the health, so if you are going to try them, I would only get them from a reputable source.

They actually look quite pretty in some of the pictures I've seen of them and I am quite partial to blue cheese (while most of my family hates it) so I would definitely give them a shot. But only if I knew they were safe.


There are quite a few ways of preparing eggs in China that people from other countries would find strange. The strangest way I've ever heard of, though, are the eggs prepared in one region by boiling them in urine. This is supposed to make them beneficial to health, but I'm not sure I could bring myself to eat them, even for a dare. I might be willing to try a century egg.

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    • Century eggs are considered a delicacy in China.
      By: pavalena
      Century eggs are considered a delicacy in China.