Century eggs, also known as hundred-year eggs, thousand-year eggs, millennium eggs, or pine patterned eggs, are a Chinese preserved egg product with a unique taste and appearance. The eggs are preserved through an extensive process of salt curing and alkalization, which gives them a gelatinous texture and an aromatic flavor profile.
Century eggs have a long history in Chinese cuisine, dating back centuries. They are considered a delicacy and are commonly eaten as a side dish, appetizer, or ingredient in other dishes. Some key questions around century eggs include:
What are century eggs made of?
Century eggs begin as regular chicken, duck, or quail eggs. They are then preserved through a multi-week process of coating and soaking in a brine made from clay, quicklime, ash, salt, rice hulls, and other alkaline materials. This process causes the egg white to turn into a dark brown, translucent jelly while the yolk becomes a grayish-green color with a creamy, cheese-like consistency. The alkaline coating helps prevent bacterial growth and penetration of air and moisture.
What do century eggs taste like?
The flavor of century eggs is unique and difficult to compare to other foods. The egg white has an earthy, mineral-y, faintly meaty or seafood-like taste. The altered yolk is rich, creamy, and occupies a space somewhere between a ripe Camembert and creamy blue cheese. The overall taste is savory and complex, with no singular analogue in Western cuisine.
Are century eggs safe to eat?
Despite their unusual appearance and flavor, century eggs are considered safe to eat. The alkaline mixture prevents the growth of harmful bacteria, while the salt works to draw moisture out of the eggs. The pH of finished century eggs is around 9-12, well above the level where salmonella can grow. As long as they are prepared properly, century eggs pose no more food safety risks than regular eggs.
Where are century eggs from?
Century eggs originated in China, where they have been produced for centuries. The exact origins are unclear, but some accounts date back as far as the Ming Dynasty (1368–1644). The provinces of Beijing, Shandong, Fujian, and Guangdong were historically major centers of century egg production. Over time, the popularity of century eggs expanded to other parts of East and Southeast Asia.
Are century eggs rotten?
While their unusual appearance may be off-putting to some, century eggs are not rotten. The curing and preservation process intentionally alters the color, flavor, and texture of the eggs through controlled chemical changes. A properly cured century egg will not have a foul or noticeably ammonia-like odor like a rotten egg. The translucent brown egg white and green yolk are the intended results.
Production Process
The traditional process for making century eggs is time-consuming and meticulous. It involves multiple stages over several weeks:
Selection
Eggs are carefully inspected for cracks or flaws. Duck eggs are preferred over chicken eggs for their higher fat content, which produces a richer final product. Larger eggs are also favored.
Mixing the Curing Paste
A moist paste is made from ingredients like clay, quicklime, ash, salt, and rice hulls or tea leaves. The specific ingredients and ratios vary by region and producer. This alkaline paste will initiate the curing process.
Coating
The curing paste is thickly smeared over each egg until completely covered. Eggs are then placed upright in rows in wooden racks or jars. The containers are covered to prevent drying out.
Curing
Eggs cure for anywhere from 2-6 weeks. During this time, the alkaline coating penetrates the eggshell and begins transforming the inner proteins. Ideal curing conditions are 65-80°F with 75-85% humidity. The curing paste may be reapplied weekly.
Rinsing
Once fully cured, the hardened paste coating is rinsed and scraped off. This reveals the century egg inside.
Drying and Storage
The cured eggs are left to dry for a few days, then rubbed with rice chaff to minimize sliminess. They can be consumed immediately or wrapped in cloth, plastic, or salt for extended storage.
Consumption and Uses
Century eggs have versatility as an ingredient and side dish. Some popular ways they are consumed include:
On Their Own
Century eggs are delicious sliced up and enjoyed on their own, similar to hard boiled eggs. Their unique appearance when cut open is part of the appeal.
In Congee
Adding cubes of century egg to rice porridge is a beloved breakfast combination in many parts of China. The flavors marry beautifully.
Stir Frys
Sliced century eggs can be added to noodle and vegetable stir fry dishes. They provide a savory umami punch.
With Preserved Vegetables
Pairing century eggs with pickled vegetables like suan cai is a refreshing blend of flavors and textures.
As Street Food
Century eggs are commonly found as street food skewered on sticks or as filling in jianbing savory crepes.
In Mooncakes
Some Chinese mooncakes feature a whole mini century egg baked inside along with lotus seed paste.
As a Topping
Thin slices or small chunks of century egg can top dishes as a garnish in the same way hard boiled eggs are used.
In Salads
Wedges or slices of century egg lend intrigue to otherwise simple salads of lettuce, tomato, cucumber, and onion.
Regional Differences
While the general technique stays the same, the production of century eggs varies across China and Asia based on local customs and ingredients. Here are some notable regional differences:
Beijing
Beijing style traditionally uses black tea leaves in the curing paste, which lends a reddish-brown hue to the finished eggs. The tea is believed to help enhance the flavor.
Shandong
Shandong province favors using raw pumpkin juice or spirulina algae in the alkaline coating mixture. This is said to give the eggs a more vivid coloration.
Guangdong
Guangdong style cures the eggs especially long – up to 2 months. This extended process produces eggs with a higher ammonia content and more pungent flavor.
Vietnam
In Vietnam, century eggs are called trứng vịt lộn. Vietnamese style often coats the eggs in a viscous, clear gelatin made from stewed rice.
Thailand
Thai century eggs are known as khai yiao ma. Wood ash and limewater are more commonly used than clay for curing.
Nutrition
From a nutritional standpoint, century eggs are comparable to regular hard boiled eggs. The curing and preservation process does not significantly alter the macro- or micronutrient contents of the eggs. According to the USDA, a 50 gram serving of century egg contains:
| Nutrient | Value |
|---|---|
| Calories | 55 |
| Protein | 6g |
| Fat | 4g |
| Carbs | 0.5g |
| Calcium | 25mg |
| Iron | 0.5mg |
| Potassium | 63mg |
Century eggs are high in protein, minerals like iron and calcium, and micronutrients such as selenium, vitamins A and B12. The lipid profile is similar to regular eggs, with a mix of unsaturated, saturated, and phospholipid fats. Overall, century eggs can be part of a balanced diet in moderation.
Safety Concerns
When properly manufactured, century eggs are a safe food product that poses no additional health risks compared to regular eggs. However, there are some safety considerations to keep in mind:
Quality Control
Substandard processing techniques could potentially result in contamination or presence of heavy metals. Only reputable, regulated producers should be trusted.
Food Allergies
Those with egg allergies should avoid century eggs. The proteins will still trigger allergic reactions.
Freshness
As with normal eggs, century eggs can still spoil over time after curing. Eating rotten century eggs can cause food poisoning.
Lead Exposure
Some early century egg recipes included lead oxide to darken the egg white. Modern standard practices avoid lead, but unregulated producers could still introduce risks.
Food Sensitivities
The distinctive ammonia odor can be off-putting for some. Start with a small portion to see if century eggs agree with your digestion.
Conclusion
Century eggs hold a unique place in Chinese culinary tradition thanks to their distinctive appearance, taste, and smooth, creamy texture. While the unusual preservation process may seem strange initially, it results in a safe, shelf-stable egg product that can be enjoyed in moderation as part of a varied diet. With their rich, savory flavors, century eggs pair wonderfully with rice congee, vegetables, noodles, and other ingredients. From street food to fancy banquets, century eggs are beloved through many regions of Asia. As long as they are produced properly using quality eggs and materials, century eggs can offer a delicious and intriguing new experience for egg lovers around the world.