Chinese cuisine

The Secrets of China’s “Secret Sauce”

Chef Peter starts his work day each afternoon by mixing a fragrant broth of garlic, ginger, soy sauce, sugar and a boatload of spices.

Then he carefully unwraps a plastic bag with his secret ingredient: a 40-year-old sauce.

“It’s just a small part of the dish, but it’s crucial for the overall taste,” says Peter.

The sauce is called Read (pronounced “loo”), and virtually every regional Chinese cuisine uses some variation of it. Lu sauce originally referred to salt water used as a marinade for boiled meat, then served cold, and for vegetables. Nowadays, it’s made from a salty liquid base, like soy sauce, with sugar and a spice mix. And it’s not just a marinade — it’s also used to finish the dish once it’s cooked.

Lu is the secret sauce at the heart of many Chinese home cooking. For Peter, his Lu Sauce is also a legacy from his beloved mother.

/ Aowen Cao/NPR

/

Aowen Cao/NPR

Chef Peter uses a bit of his mother’s original sauce for every batch he cooks up at his restaurant. Other ingredients: garlic, ginger, soy sauce, sugar and a load of spices.

“Every time I cook with Lu sauce, I feel sure-footed. I feel like I’m closer to my mother’s taste,” says Peter. He learned to cook from his mother, who often exchanged cooking tips with him after she left her native Shanghai to work in northern China.

During one of his last home visits in 2015, before his mother passed away, she gave him some of her Lu sauce to take with him to Beijing, to make him feel closer to home.

An ancient sauce built around salt

Lu sauce originally referred to salt water used as a marinade for boiled meat, then served cold, and for vegetables.

“Salt is the heart of Lu sauce, even more important than spices. Spices can add flavor or eliminate certain odors, but it is salt that is crucial for flavor,” says Cao Yu, writer and historian of food at the University of Jinan.

The first recipes kept for making Lu date back to Qimin Yaoshuan ancient Chinese agricultural text written in the 5th century: “Mix together 160 liters of water and three liters of salt, then boil to make the Lu.”

Cao believes the Lu sauce we know today originated around the Ming Dynasty more than seven centuries ago, when agricultural enterprises and privatized food markets began to appear in China. To attract customers, these food vendors began to introduce new flavors into the sauce by adding spices as well as soy sauce for color, then using the sauce to season cooked meats and vegetables sold cold at carry,

Over the centuries that followed, Lu diversified, taking on the characteristics of each of China’s regional cuisines. For example, in the spicy province of Sichuan, fragrant pepper and star anise are infused into Lu to add flavor and intensity.

Some Lu are even alcoholic: Zao Lu is a light marinade made from fermented sticky rice mash left over from brewing Chinese yellow wine. Zao Lu is used throughout southeast China to season vegetables.

His sauce came straight from his mother

The Lu sauce Chef Peter uses in his restaurant comes from an unbroken chain of sauces dating back to the first batch his mother made in the 1980s.

Today, he still maintains that original Lu sauce by giving it new “nutrients” every day – a fresh infusion of spices and meat, which is boiled in the sauce to enrich it.

“You have to raise an old Lu sauce, like raising a child,” Peter mused.

Peter always saves the rest of each batch of Lu and uses the old sauce to start the next new batch of sauce. It’s kind of like sourdough, where the last batch sows the next batch, and the flavor intensifies over the years.

“Think about it: my duck sauce Lu was started by my mother in the 1980s, so in a dish of braised duck Lu, you are eating the essence of at least seven or eight thousand ducks that have been there” , he said. “My sauce is really an accumulation of time.”

As a result, Peter does not like receiving customers in a hurry. Like an old wine, he says, you have to mull over Lu sauce carefully to appreciate its rich finish: oily, sweet and salty.

After four hours of slow simmering, Peter’s sweet Shanghai-style Lu turned into a thick, dark soup. Peter reduces it further until it becomes a molasses-like syrup.

The intense, ancient Lu sauce has made Peter’s restaurant, tucked away in an unmarked residential apartment, a well-hidden gem in Beijing, advertised only by word of mouth. Peter expressly forbids us from using his full name or mentioning his restaurant in this article.

“We have a saying in Chinese: fame brings trouble. This restaurant is my playground. I don’t want too many people to come.”

Copyright 2022 NPR. To learn more, visit https://www.npr.org.