Serious Eats: Recipes

Phở Đuôi Bò (Vietnamese Noodle Soup with Oxtail)

Phở đuôi bò. [Photographs: Tam Ngo]

Since we'll be stuck in dark drizzle for months to come, let's talk about phở, a perfect food for chasing away the doldrums of winter.

Phở bò is a Vietnamese beef noodle soup; phở đuôi bò is one made with oxtail. Regardless of meat choice or spice, the prototype is plush with the mouthfeel of gelatin, springy noodles, and bright herbs.

Phở originates from northern Viet Nam but the whole country sups the soup with patriotic zeal. Phở broth in the north tastes honestly of the meat and bones it's cooked with. The further south, the more likely you'll find it spiked with the warmth of anise, clove, cinnamon, and the like.

My-Man-of-Eternal-Patience and I have been tinkering with our recipe for several years now. Starting with Mai Pham's ingredients and Andrea Nguyen's tips, we threw in the accumulated wisdom of a few Vietnamese mums for good measure.

Fat Tails vs. Lean

In prior takes, we left the oxtails with fat intact and skimmed only afterwards. In this version, we trimmed the fat before simmering the tails to see if this saved time or hurt flavor.

Roasting vs. Parboiling

French-trained cooks eschew parboiling and advocate pre-roasting the bones to build a deeper broth. Vietnamese cooks skip the roasting but parboil to create a cleaner broth. For each technique, you'll find yay-sayers on both sides. We decided to do a taste-test to see if one method yielded more favorable results.

More Time = More Awesome?

In this round of experimentation, we also increased the simmering time by 20-percent. After finding a 8-hour broth to be enormously richer than a 4-hour broth, we figured a 10-hour broth would be nothing short of effin' awesome.


Spice mix, cha cha cha.

The Results

Epic. Fifteen pounds of oxtail + ten hours = four gallons of two broths. I'm still cleaning blood from under my fingernails.

Fat Tails vs. Lean: Interestingly, we found that the Asian grocer H-Mart tends to sell thick, uniform cuts of oxtail with more meat than fat. Generic supermarkets such as Wegman's sell oxtail, variably sized, with rinds of yellowed fat and substantially less meat.

In the past, leaving the tails with fat intact gave us a impressive strata to skim afterwards. But not all the fat seemed to rise to the top. The broth had stretched squiggles I originally pegged as gelatin. I now suspect that what we saw was residual fat captured in gelatin. (This is based on sight and comparative mouthfeel, but I'm dying to know if this jives with science.)

In this experiment, we trimmed two pounds of fat pre-simmer and skimmed another half pound post. Upon serving, we reserved roughly the same amount of liquid fat in the soup as in earlier versions. And while the flavors of the soup still dazzled, it didn't luxuriate in the mouth as it did before.

Roasting vs. Parboiling: Roasting the bones led to beefier emanations. Unfortunately, that essence of beef dulled all other flavors, including the aromatics it simmered with. The broth was opaque, less fatty, but lots more scummy. Tasting it cold was pleasant enough. But heated through, it tasted monoflavored if not flat. From Day 1 to Day 3, the degradation of flavor was dramatic. As each day passed, each taste was muddier than the last.

Parboiled bones produced a fattier broth but with minimal scum. What was startling was the resulting clarity of flavor. We were able to appreciate the spices individuated and in concert. Sipped cold, the broth could pass as a refreshing beef-beverage, and heated through, the taste was just as vivid. Day 1 was enjoyable; Day 2 even more so. Even as late as Day 3, the broth held up.

More Time = More Awesome? In terms of simmering time, a 10-hour simmer did not taste appreciably better than an eight. Unfortunately, the meat suffered at the hands of extra time. Past some optimal point, the longer it stewed, the more the tail toughened. The sweet spot in time is probably somewhere between 6 to 8 hours. Also of note: fattier cuts of tail are better moisturized to survive long durations of heat.


Oxtail tableau.

Truly great dishes travel far from their origins. The changes made to them can reflect poverty, abundance, climate, even evolving attitudes. While there are many recipes out there with purists to defend them, this phở reflects my parents' own migration, from north Viet Nam to south and marries the best both have to offer. Simmered with rich oxtail and a generous amount of spice, this soup's got flavors both deep and bright.

Phở Đuôi Bò (Vietnamese Noodle Soup with Oxtail)

I like my phở broth silky with gelatin but not slick with grease, so I skim the fat pretty aggressively. To cut down on skimming efforts and to allow flavors to fully develop, I give myself a couple of days to build the broth.

Most cookbooks call for a three-hour simmer of shank bones, but an eight-hour simmer of oxtail yields a deeper, darker, more robust soup. The meat practically shudders off the bone. The trick to simmering the soup? Low + slow.

On Day 1, simmer the broth, cool, and refrigerate it overnight. On Day 2, scoop off the crust of coagulated fat and reheat the broth to serve. A lot of the broth prep is passive cooking, that is, merely keeping an eye on a barely-bubbling cauldron. In that sense, the recipe's perfect for bad rain and a good book.

Makes 8 large bowls, or 6 phở xe lửa-sized bowls (approximately 5 quarts of broth). Uneaten broth can be scooped into single-serving plastic tubs, frozen, and refreshed with ginger upon reheating.

Day 1: Broth Building


Stock pot (minimum capacity of 12 quarts, for cooking bones and broth)
Stock pot (minimum capacity of 6 quarts, for cooking noodles)
Wide skillet
Tongs or long-handled wooden chopsticks
Long-handled fine-mesh skimmer (for straining fat)
Chinois or mesh strainer lined with cheesecloth (for straining scum)
Long-handled large-mesh basket (for blanching noodles)
6 to 8 deep, wide-mouthed bowls for serving

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