guide pho herbs spices

A Guide to Pho Herbs and Spices

All the herbs and spices that give pho flavor.

The aromatic herbs and spices used in pho vary from region to region and chef to chef. In Northern Vietnam, where pho comes from, the soup features an aromatic stock full of the spices that grow in abundance in that cooler mountainous region: star anise, cinnamon, and black cardamom. In the South, pho comes with the familiar plate of herb garnishes that Americans expect with their bowls.

1. Black Pepper (hat tieu)

Black pepper has been cultivated since at least the fourth century in Northern Vietnam. The spice consists of unripe berries from the tropical climbing vine Piper nigrum that have been blanched and dried. As the berries mature on the vine, their concentration of the spicy alkaloid piperine increases, while other aromatic molecules decrease. That’s why white pepper, made from ripe berries whose skins have been removed before drying, is as hot as black pepper but has a mustier aroma.

2. Black Cardamom (thao quo)

Black cardamom has a stronger flavor than the green stuff and comes in larger pods, which is why it’s also known as large cardamom. It’s often dried over open flames, giving it a distinct smoky flavor. It’s found in cooler parts of Northern Vietnam, along the Hoang Lien Son mountain range and in the northwestern provinces of Lao Cai and Lai Chau, which explains its presence in pho bac broth.

3. Ginger (gung)

Native to southern Asia, ginger actually comprises many species that vary in their pungency and aroma. Ginger is often the dominant flavor in pho ga (chicken pho). Fresh ginger is typically charred or roasted with onion before being added to the stock, a technique picked up from the French. Cooking transforms the flavor chemicals known as gingerols into zingerone, which is spicy and sweet and less intense than raw ginger.

4. Vietnamese cinnamon (que/que qui)

Related to both Ceylon (i.e., true) cinnamon and cassia, Vietnamese cinnamon has a slightly grayish, coarse outer bark and a high essential-oil content. Although cinnamon isn’t an especially popular spice in Vietnamese cuisine outside of meat broths, it has been cultivated in Hanoi for thousands of years: the Chinese first recorded its presence there during the Han Dynasty. It adds a distinctive warmth to Hanoi-style broth.

5. Cloves (dinh huong)

Cloves are the dried flower buds of myrtle trees. Among spices, they have the highest concentration of aromatic molecules, primary among them the chemical compound eugenol (over 81 percent), which gives clove its characteristic spicy sweetness and antimicrobial properties. Cloves have been used by the Chinese since as early as 200 BCE, and their prominence in pho suggests some of the dish’s Chinese influence.

6. Star Anise (dai hoi)

Native to southwestern China and Northern Vietnam, star anise grows wild in the Lang Son Province, not too far from Hanoi, the birthplace of pho. When star anise is heated in water, its principal flavor compound, anethole, becomes an entirely different flavor molecule: anisaldehyde. Anisaldehyde has vanilla notes and interacts with cysteine, an amino acid found in meat, to produce even more new flavor compounds, which makes it a popular choice for long-boiling stocks.

7. Thai Basil (que/hung cho/rau que)

Thai basil is just one cultivar of a diverse species that includes sweet basil and at least forty other cultivated varieties. It has a purplish tinge to its leaves and stems, and a more anisey flavor profile than sweet basil. (Its Vietnamese name, hung que, translates literally to “cinnamon mint.”) Thai basil is commonplace on the herb platters that accompany bowls of pho around the world, but it’s actually a specifically Southern Vietnamese addition; traditionalist Northerners view its inclusion in pho as sacrilege.

8. Bird’s-Eye Chili (ot hiem)

Bird’s-eye chilies are the most popular variety in Vietnam. Known as ot hiem (literally, “dangerous chili”), they’re much spicier and more fragrant than the sliced jalapeños typical at American pho joints. You’ll find bird’s-eye chilies at pho shops all over the country in both fresh form and as ot chung, a fermented paste of garlic, salt, chilies, and sugar. (Tuong ot, which is boiled rather than fermented and features the addition of tomatoes, is another chili sauce you might find served with pho.)

9. Mint (hung lui/rau hung lui)

Varieties of mint—there are many in Vietnam—make their way onto herb platters throughout the South. Hung lui is spearmint, but there’s also bac ha (peppermint) and hung cay (spicy peppermint). Water mint (hung dui)—a variety with oval leaves, a subtle citrus scent (it’s also called bergamot mint), and a very pungent flavor that can stand up to hot broth—is an essential component of authentic Hanoi pho.

10. Culantro (ngo tau/ngo gai/mui tau)

Culantro, also known as sawtooth herb, has become popular in Vietnam’s hotter climates. Its flavor is like a stronger coriander leaf: the aroma comes from a longer version of the fatty aldehyde found in coriander. The leaves are long, serrated, and tough, which make them less prone to wilting in hot soup. It’s uncommon in the U.S., but you’ll find it at almost every pho shop in Saigon.

11. Cilantro (ngo/mui)

Cilantro’s main aromatic component is the highly reactive decenal, which loses its flavor when cooked and is therefore sprinkled on pho just before serving. It’s found whole or roughly chopped in pho bowls all over the world, although some Vietnamese opt for the bright, bitter notes of culantro instead.

12. Vietnamese Coriander (rau ram)

In Southern Vietnam, rau ram is found on herb platters at more generous pho shops, where it adds lemony, cilantro-y notes and a peppery kick. In the Central Vietnamese city of Hue, you’ll find the purple-tinged leaves in chicken salad and bun bo Hue.

13. Vietnamese (balm kinh gioi)

Cultivated extensively throughout Vietnam for both culinary and medicinal purposes (it’s used to treat sore throat and measles, among other things), Vietnamese balm tastes like lemongrass and is often found on the herb plates accompanying pho in the South. The veiny, serrated leaves of this purple-flowered herb are reminiscent of perilla (they’re both in the mint family), but they’re smaller, with less dramatic ridges. It’s also essential in banana-blossom salad, the Saigonese crab noodles bun rieu, and Central Vietnam’s spicy beef noodle soup bun bo Hue.

14. Rice-Paddy Herb (ngo om/rau om)

Native to Southeast Asia and difficult to find anywhere else, rice-paddy herb has a lemony, cumin-like flavor. It is often cultivated in flooded rice fields. Each stem is full of tiny leaves that lend their characteristic flavor to canh chua, a sweet and sour fish soup from the South.

15. Peanut Worm (sa sung)

Sa sung is a dried marine worm by the name of Sipunculus nudus. These worms range from two to six inches in length and are found in tropical waters across the globe, with a particularly high concentration in the Quang Ninh Province on the northeastern coast of Vietnam, where they make their home in the muddy subtidal flats found around that region’s estuaries and 2,000-plus islands. They’re known as peanut worms in the West, because they resemble peanut shells when they’re small and bunched up. The worms bury themselves in sand-rich sediment and remain submerged underwater for ten to eighteen hours a day. Their insides are filled with sand, so they must be toasted, split open, and cleaned before going into the pho broth. They add a strong umami flavor and subtle sweetness to the broth that some cooks recreate with a combination of MSG and yellow rock sugar. They’re extremely uncommon in the States, and in fact are in danger of overexploitation in Vietnam. They also take up minerals from their environment and, due to bioaccumulation, can contain heavier concentrations of pollutants, such as heavy metals, than the surrounding environment.