JUANA SUMMERS, HOST:
One of the great cornerstones of Chinese culture is its food. And at the heart of China's many regional cuisines is one secret sauce. NPR's Beijing correspondent Emily Feng brings us into a kitchen to discover what it is.
(SOUNDBITE OF FOOD SIZZLING)
EMILY FENG, BYLINE: Chef Peter begins his day at 2 p.m., mixing together the garlic, ginger, soy sauce, sugar and a boatload of spices that form the base of his cuisine. Then he carefully unwraps a plastic bag with his secret ingredient. It's a sauce that's 40 years old.
PETER: (Through interpreter) This is just one small element, but it's crucial to the overall taste.
FENG: The sauce is called Lu or Lu Shui. And basically every Chinese regional cuisine uses some variation of it. Usually it's made out of a base of salt, such as soy sauce, sugar and a mix of spices. And to Peter, the sauce is a living, breathing thing.
PETER: (Through interpreter) You have to raise an old Lu sauce like raising a child.
FENG: You might be wondering by now - the sauce is not literally 40 years old, but it comes from an unbroken chain of sauces dating back to the first one his mother in Shanghai made in the 1980s. Peter always saves the remainder of each Lu batch and uses the old sauce to start the next new batch of sauce. It's a bit like sourdough, where the old seeds the new and the flavor intensifies over the years. This is the way most Lu sauces are made.
PETER: (Through interpreter) Think about it. In one dish of Lu-braised duck, you're eating the essence of at least 7,000 or 8,000 ducks that have passed through it.
FENG: Once, an unknowing waiter threw out the Lu sauce Peter was saving for the next day's dishes.
PETER: (Through interpreter) I fired him. Those who are in the business know that this Lu is like my life. And it's a little part of my mother. So throwing it away is like disrespecting my ancestors' tombs.
FENG: Cao Yu, a food writer and historian at Jinan University, says Lu at first simply denoted any kind of salt water used as a marinade for cold boiled meat and vegetables.
CAO YU: (Through interpreter) I believe the emergence of the Lu we know today is around by the Ming dynasty, more than seven centuries ago, when you saw the emergence of privatized businesses and markets.
FENG: To attract new customers, these new private food vendors began introducing new flavors and new ways to cook Lu, by adding spices or soy sauce for color. In the centuries since, Lu has diversified, taking on the characteristics of each regional cuisine. For example, in spicy Sichuan province...
YU: (Through interpreter) Lu is used to add flavor and intensity. So Sichuanese use a ton of spices in their Lu. But in Cantonese cooking, they want the flavor of the ingredients to come out. So they use far less salt and spice.
FENG: Some Lu is even alcoholic, like Zao Lu, a light marinade made from the fermented glutinous rice mash left over from brewing Chinese yellow wine, or huangjiu.
(SOUNDBITE OF SPATULA SCRAPING PAN)
FENG: Four hours later in Peter's kitchen, his much sweeter Shanghai-style Lu has simmered down to a dark, thick soup. Peter reduces it further until it becomes a molasses-like syrup.
PETER: (Through interpreter) The sauce coats each morsel. The juices mix evenly with the fat of the pig trotters in this case.
FENG: The intense old Lu sauce is what's made Peter's restaurant a well-hidden gem in Beijing through word of mouth only. In fact, Peter expressly forbade us from using his full name or mentioning his restaurant in this piece because he does not want too many customers
PETER: (Through interpreter) We have a saying - fame brings trouble (laughter). And this restaurant is my playground. I don't want too many people to come.
FENG: Cooking each night is also a little risky. Peter says he goes all-in every time, using up all his old Lu sauce for pork, beef and duck for each dinner - no backups, no insurance policy.
(SOUNDBITE OF FOOD SIZZLING)
PETER: (Through interpreter) We're extremely careful - extremely careful with the sauce.
FENG: I ask about vacations. Would he ever entrust another person to feed and take care of his Lu sauce if he's away? No, Peter says. The sauce is just too important to him.
Emily Feng, NPR News, Beijing. Transcript provided by NPR, Copyright NPR.
