Homemade Salted Duck Eggs

Nothing makes me think of Nanjing like salted duck eggs—fresh duck eggs preserved in a salt brine, or more traditionally, salty alkaline clay. The process slowly draws all the water content out of the egg and infuses it with sodium, turning the white of the egg, when cooked, into a pickled version of itself—gelatinous, briny and lightly sulfuric. The yolk becomes a translucent orange orb, with taste and texture most akin to the crystals you sometimes find sprinkled throughout very old, very fine Parmesan or Gouda: a sandy, fatty jewel of umami.

It’s not just that Nanjing is the “duck capital” of China, accounting for some 100 million ducks consumed annually (and, one presumes, some order of magnitude more duck eggs). It’s not even that Jiangsu Province is where salted duck eggs were invented over a thousand years ago. More simply and selfishly, I was raised on salted duck eggs. I was a picky eater, and late ’80s China was pre-reform, pre-wealth China; options were limited. My parents found that the easiest way to deliver enough fat and protein into my mouth was by scooping out a precious half of a salted duck egg and feeding it to me with congee. One half for lunch, the other for dinner.

Yes, in Nanjing, a salted duck egg is always hard boiled, then sliced lengthwise shell-on, so one can scoop it out sparingly. One always saves the yolk—the best part—for last.

One day, this was no longer true, and my understanding of salted duck eggs was turned upside down—along with my understanding of China itself. It was in 2011, the summer before I started culinary school in Nanjing. I had just arrived, and one of my flashier uncles treated me to lunch at a place I never could have found, or afforded, myself.

They served a dish of skewered shrimp, arrow-straight, fried crispy and coated in a deliciously salty, funky, thickly rich MANNA of a sauce—salted egg yolk sauce. I imagined it must have taken dozens of yolks to make such a stupendous sauce. I imagined daring feats of culinary physics to get them to liquify, to adhere to shrimp. I imagined a pile of lonely whites in the kitchen, waiting for a lowly congee that would never be served.

I tasted China’s newfound prosperity before I ever studied it in books.

How Did Salted Yolks Become a Ubiquitous Ingredient?

If one traces the timeline in English-language news, media outlets in Singapore start naming salted eggs the hot new ingredient around 2015. Indeed, 2014 is when family-run Irvin’s of Singapore—now an international juggernaut—first started experimenting with putting salted egg yolk sauce on potato chips.

By 2016, the Specialty Food Association here in the United States has caught on, predicting “Salted Egg Yolk to be the Next Flavor Trend.” In 2017, Spoon University publishes a wistfully envious piece entitled 20 Salted Egg Yolk Dishes You’ll Wish Were Served in the U.S. Not to worry, U.S. food writers and restaurants are on it—the next five years deliver a flurry of salted yolk recipes and menu items. By 2022, one could argue, we had reached Peak Salted Egg. This is the year that Torani, of the flavored coffee syrups, releases a Salted Egg Yolk Syrup, naming it the “Pourcast Flavor of 2022.” Helpfully, Torani’s sales brief clarifies that this stroke of mad genius is “designed for culinary tourism,” and provides recipes for salted egg milkshakes, chai, bubble tea and cold brew.

It is now 2023, and NBC News—bastion of square old mainstream media—just did an article headlined “The Rise of the Salted Egg Yolk.” The takeover is complete.

But let’s go back a little bit: Years before the salted egg trend was identified in the United States, or even in Singapore, it had already swept mainland China. When I tasted that unforgettable shrimp dish in 2011, this was the trajectory that China’s GDP per capita was on:

And relatedly, this is how many people were contributing to the boom times by moving to big cities:

In other words, between the time I was born and the time I tasted that dish, the percentage of Chinese people living in cities had doubled—to 50%—and people’s average incomes had grown twenty-fold, from $282 to $5600!

People could afford more than one duck egg for their only child, divided between lunch and dinner. And because they were living in cities and working city jobs, they were eating in restaurants more—the urbanization graph is also a tidy encapsulation of the post-reform explosion of Chinese restaurants and all the incredible new dishes they invented. It was no doubt a Chinese restaurant chef during this period who rebranded salted yolks into the ultimate signifier of wealth: 金沙 (jīnshā), “golden sand.”

Why You Should Make Your Own Salted Duck Yolks

 

Salted duck eggs don’t actually cost very much money today, especially not when compared to other luxury-coded ingredients like truffles or caviar. You can buy a blister pack of frozen yolks online for $7. But I think Chinese people have a cultural memory of when duck eggs were precious. Even city-dwellers are less than one generation removed from carefully curing the eggs themselves, waiting a month or longer for the reward. And we are all perhaps less than two generations removed from raising the ducks ourselves (my father did it as a child), with the wait longer still. I think this context adds to my sense of luxury when eating a surfeit of salted yolks—hunger is the best seasoning, even if it’s just a memory.

Therefore, I think it’s well worth it to make your own salted eggs. A more practical reason: You can control the salt level, and you get much fresher eggs. A common gripe my mom has with store-bought salted eggs is that they are too salty, especially the whites, and the yolks almost never have the prized oil droplets that signal ultimate quality and freshness. The global supply chain is impressive, but it still has its limits. My recipe calls for a relatively low salt concentration. After a month, they are mildly salty. If you leave them in the brine, they become steadily saltier.

Brining Basics

This recipe calls for a dozen duck eggs, which I feel is the minimum you’ll want if you’re committing to a month-long brine. The Mala Market’s ceramic pickle jar holds two dozen eggs comfortably, so just double the recipe if using that jar. I like the shape of it—its shoulders help keep the eggs submerged. Otherwise, you may need to use a weight to keep eggs below the waterline, which is important for preventing spoilage.

Some helpful weight ratios for adjusting quantity, no matter how many eggs or what kind of brining vessel you use:

• 1:1 eggs to brine
• 1:5 salt to water

Even though this process is a cure and not a ferment, temperature does have an effect on the osmotic processes that transform the egg. The egg is ready when all the water has slowly been drawn out of the yolk and the sodium it has absorbed has caused it to extrude oil. In warm temperatures (above 75F), check the eggs after 3 weeks. If you shake one gently and can hear a solid yolk bumping around, that means it’s ready. In the wintertime (or a cold pantry or basement), it may take up to 40 days.

Seleggtion

No, chicken eggs are not a good substitute. A duck’s yolk is ⅓ fat, a chicken’s is ¼, meaning you won’t get the same richness or oil extrusion from a chicken egg. Plus, the flavor is very different (read: vastly inferior).

Use the freshest, highest quality duck eggs you can find. Do not use any eggs that have cracks. If you notice the brine going cloudy, you probably have a cracked egg. In this event, remove all the eggs, dispose of the cracked one, and make a fresh batch of brine.

A Note on Separating and Cooking the Yolks 

Salted yolks need to be cooked before they can be used for a sauce. You can either hard-boil whole eggs and separate the yolks (reserve the whites to eat with congee!), or separate the yolks from the liquid whites and steam them in a bowl. For the former method, you’ll want to boil for 10 minutes to get yolks that mash easily but are still deeply golden-hued. For the latter method, steam for five minutes.

Golden Sand Corn

With the invention of “golden sand,” salted yolks moved from the realm of garnish to the realm of the main course. Golden sand, that is, liquified salted yolks, is now used as a coating sauce for everything from kabocha squash to mushrooms to shrimp, and as a filling or seasoning for myriad pastries.

Golden sand corn is a favorite of mine—the eggy funk pairs beautifully with starchy-sweet corn kernels—and it is very 下饭 (xiàfàn), rice friendly. I especially love serving this dish as a reprieve alongside lots of spicy foods, since the egg yolks have the same effect as a tall glass of milk.

Try to use a starchy, fat-kerneled corn for this recipe rather than American sweet corn, which I find both too sweet and too watery. Mom and I both love the pre-cooked vacuum-sealed corncobs from Asian grocery stores, but frozen kernels work well too. When you make the sauce, don’t be tempted to skimp on oil. Without enough oil, the yolks have nothing to dissolve into, and you won’t have enough sauce to properly coat your ingredients.

A final tip: this dish is about eating with your eyes. Don’t be tempted to splash golden sand sauce with Shaoxing or soy, which both ruin the hue. Keep the flame low and cooking time short for the same reason.