The Dish: Phnom Penh's Sour Fish Soup

By KAREN COATES

Wall Street Journal

It seems most every Khmer is born with a batch of sour fish soup in the blood. It's considered mahop tourmada, or "everyday food," in the local lexicon.

Jerry Redfern for The Wall Street Journal

Sour fish soup is the ultimate Khmer 'everyday food'. The dish derives its tang from tamarind pulp (and sometimes the leaf). It's fortified with fresh fish; packed with wild green water grasses, or trou kuon; flavored with fermented fish paste, prahok; and scented with the minty herb ma'om, which freckles the edges of rice paddies across the cultivated flats of Cambodia.

"It's an everyday soup, cheap and easy to make," says Narin Jameson, who is writing a cookbook of Khmer recipes intertwined with stories of her Cambodian childhood. "I did not like [the soup] when I was growing up," says the 65-year-old Ms. Jameson, who fled the country in the 1970s during wartime and later settled in the U.S. with her husband, an American diplomat. "But now I love it…especially when I am away from home." She uses a term, trou kuon tip—one bowl, another bowl, until you cannot take it anymore—to describe the "magic" in a soup that compels a person to keep eating more and more.

You'll find a slew of sour soups across Cambodia, but the simplest of all is samlor machou trou kuon trey, sour fish soup with water grass or "morning glory." It requires just a handful of key ingredients and takes but five minutes to cook. "In the olden days, it was a soup for peasants," says Ms. Jameson.

THE HISTORY

Khmers say they can't remember a time when the taste of sour fish soup wasn't imprinted on their tongues. "When I was first born, I knew about it," says Meng Hieng, who has run a no-name restaurant on a Phnom Penh sidewalk for 20 years. Like other restaurateurs and connoisseurs across the Cambodian diaspora, he knows no textbook history of the dish. But he can vouch: It's one of the most popular orders at his shop, which also serves noodles, stir-fries and rice.

Most any Khmer kitchen has the fixings for an array of sour soups (samlor means soup, machou means sour), which can be made with fish (trey), pork or beef; and occasionally, a pounded paste called kreung, that features lemongrass, galangal, turmeric, garlic, shallots and herbs. It's healthy food that helps "refresh" or "recharge" the body, says the noted Khmer chef Luu Meng, who runs several Phnom Penh restaurants, including Malis and Topaz. He says he believes that Cambodians have eaten sour soup for thousands of years.

It relies on fresh ingredients that are easy to grow and are readily available. It's also medicinal. "The tamarind is eaten for cleaning the throat. It's good for coughs," says Om Sophoan, a chef at Khmer Kitchen in Phnom Penh.

Most Cambodians still eat sour soup at home (most Cambodians eat all their meals at home). But times are changing in the capital city Phnom Penh, which is clogged with workers. Migrants from other provinces need cheap mahop on the street, while the upwardly mobile can—and often do—pay someone else to make their comfort food. Today, sour fish soup is slurped on nearly every Phnom Penh avenue.
THE SETTING

Given its humble pedigree, some upscale menus omit sour fish soup. If it's not listed, ask the chef, who undoubtedly knows the recipe—"Everyone knows," Mr. Meng says—and likely has the ingredients on hand.

That said, the soup is most commonly found at roadside stalls serving vats of ready-made "fast food," or quick dishes made to order. Locals say sour soup is eaten at lunch or dinner, but never breakfast. Why not? It just isn't, Mr. Meng insists. That's tradition.
THE JUDGMENT

In the kitchen of Boeng Keng Kang Restaurant, chef Meak Bora has all the essentials lined up in little white bowls: thick slices of snakehead fish, a bunch of trou kuon, a mixture of salt, sugar and MSG, slivered chili, tamarind, galangal, shallot, lemongrass, kaffir lime leaf, fish sauce, prahok and ma'om. "Everything here is important," he says. Miss one ingredient and "it's no good."

Every cook has an opinion on the best recipe for sour fish soup, but on this Khmers agree: A good batch of samlor machou trou kuon trey requires a delicate balance of sour and salt, as well as appropriate fishiness. The latter is most commonly achieved through a small dollop of the pungent fish paste prahok, although some cooks use fish sauce. The minty chopped ma'om renders the finished dish complete. "It's important," Mr. Meng says. "Good smell." Finally, the soup is almost always served with shavings of mild red chili—for color, not heat.

Additional ingredients depend on the individual cook. Touch Yorn, a Phnom Penh wife and mother of three who works at the National Library, sometimes adds fish eggs or tiny shrimp. "It's up to you if you like," she says. "A little bit of shrimp with fish makes a good taste."

When it comes to greens, however, all cooks agree: Use only wild water greens in the soup; skip the farmed variety (the two types are usually sold side by side in local markets). Sa Roeun, a vegetable vendor at Phnom Penh's Psa Chas, explains why. She eyes her pile of farmed trou kuon with its long, skinny leaves. "We can put that one in soup, but it's not a good taste," she says. Instead, the wild variety, with lighter green stems and spade-shaped leaves, tastes better in soup. She knows. She eats samlor machou trou kuon trey every two or three days. "It's my favorite."
THE SOURCE

Khmer Kitchen (25 Eo, Street 310, tel: 855-12-712-541; US$3.50 a bowl) offers indoor and outdoor seating beneath a grass-and-shingle roof in a wooden house amid a blooming garden. Choose an upstairs table and dine against silk pillows in posh comfort that attracts the NGO and embassy employees who live and work nearby. The kitchen serves numerous sour soups, including a variety with morning glory. That's the soup in question, and it ranks among the city's best: a pleasing balance of sour tamarind with a hint of prahok in a broth that tastes light and lemony. Nothing in this dish overpowers.

Meng Hieng's popular no-name restaurant (tel: 855-12-570-678; $2.50 a bowl) sits beneath awnings and shade trees on the corner of streets 90 and 61. Here, tamarind juice and leaf work together to create a fiercely tart samlor machou trou kuon trey. Tiny shrimp add dimension to the dish. The set price of $2.50, which includes rice and tea, makes this an obvious choice for drivers of tuk-tuks (motorcycle taxis) and taxis who work in the vicinity, near the city's landmark temple, Wat Phnom. The restaurant serves down-home, made-to-order traditional Khmer dishes after the early morning, noodle-soup breakfast rush, which ends around 10 a.m.

For more than a decade, the Boeng Keng Kang Restaurant (185 Norodom, tel: 855-13-626-288; $7.25 for enough soup, rice and tea to feed three) has consistently served upscale, authentic Khmer dishes to a local business crowd. Chef Meak Bora's sour soup hits a high note in the olfactory zone.

Sa Em (corner of streets 172 and 19 SE, tel: 855-12-81-2131; $2.50 a bowl) doesn't always list sour fish soup on its menu, but the restaurant serves one of the city's most delightfully fragrant versions, thanks to an abundance of minty herb. A mountain of minced ma'om tops the pale green broth filled with chunks of white fish.

—Karen Coates is a writer who splits her time between New Mexico and Asia.