The Thousand Year Old Egg: A Chinese Cuisine

When one hears the name, "thousand year old egg", it's extremely easy to assume that one's referring to an exquisite fossil or a recent scientific discovery. Though sometimes that might be the case, but for those who are familiar with Chinese cuisine, it's actually something more common than groundbreaking--it's a type of food. That's right, it's an egg that many people in the Far East eat, sometimes as often as every week. But how in the world can these people find these eggs? How would this egg be eaten so often, since, according to the name, it would take a thousand years make? Well, the answer is quite simple.

The thousand year old egg, also known as the century egg or the hundred year old egg, is actually more like the hundred day old egg, since it only takes that amount of time to make. But how it's made is the most interesting part. When creating a thousand year old egg, a regular egg (which could be from a chicken, duck, or goose) is covered with a coating of lime, ashes, and salt and then buried in a shallow hole for roughly 100 days. During this time, the lime "petrifies" the egg, transforming the egg white into a copper tinted gel, while turning the yellow yoke into a pasty grayish green. When the egg is uncovered and cleaned, it could keep fresh at room temperature for up to 2 weeks or a full month refrigerated. It can be eaten plain or served as slices mixed with hot congee and soy sauce.

Though the dark tinted white of a thousand year old egg doesn't have much taste to it, the greenish yoke is very pungent in flavor--tasting somewhat like a cheesy, highly concentrated version of a hard-boiled egg yoke. The yoke's consistency is equivalent to firm guacamole, while it's copper-toned white, like hard jello. Though mostly an acquired taste, some have grown instantly to love this egg upon first taste, while others have found it to be too overwhelming or odd for their palate.

But whether many may enjoy this cuisine or not, this exotic food brings up a simple question--how in the world does a normal egg transform into something so unique, simply by burying it?

The answer to this lies with the alkalis and the alkali earth oxides that are found in the substances that coat the egg at the beginning of the preservation process. Though many different chemical processes are involved, perhaps the most major one happens when these alkalis seep into the egg, through its shell, and disrupt the chemical structure of the proteins found within the egg white and yoke. This causes the proteins to "denature", which is the same process that happens when one cooks an egg. Once the proteins within the egg "denature", coagulation takes place causing the egg white and yoke to harden. In addition to this, the alkalis also contribute to the break down or "decomposition" of various macromolecules within the egg into smaller protein units. As a result, various compounds, such as ammonia and hydrogen sulfide (the rotten egg smell), are released, giving the egg a powerful aroma once uncovered. Because of the ammonia smell that results, over the years, it has been rumored that horse urine was involved in the production of thousand year old eggs. But this is simply a myth, given that urine is naturally acidic and, therefore, unsuitable for the production of these eggs, which require alkaline conditions.

Thousand year old eggs can be found on sale almost anywhere in a Chinatown of any major city or in most Asian grocery stores for those who live outside the city. One important thing to note, though, is that lead oxide is sometimes used industrially to expedite the process of creating these eggs, so if one's seeking to purchase a package of this cuisine, be sure to check for labels that clearly state no lead oxide.

Throughout the centuries, the egg has been subject to many culinary preparations to bring out its flavor. Some of these include, poaching, frying, boiling, seasoning, pickling, and, of course, burying. With the thousand year old egg in mind, one cannot help but wonder what else would taste better after being buried. Hot dogs perhaps? Many would hope not. Twinkies? Goodness, no. Whatever the case, the egg is perhaps one of the only foods that's wonderfully tasty and versatile...even when its yoke is green.