Som Tam Recipe: Thai Green Papaya Salad from Isan, Pounded in a Mortar

The Rhythm of Isan, Pounded in a Mortar

Walk into a back alley in Bangkok and you will hear it before you see it: a steady "pok, pok, pok." A street vendor is pounding green papaya in a clay mortar with a wooden pestle. The sound rings out with every order, and it has become one of the signature soundscapes of Thai street food.

Som tam (ส้มตำ) says it in its name: som means sour and tam means to pound, so it is literally a "pounded sour dish." It is thought to have originated in Isan, the northeastern region of Thailand, and next door in Laos it is an everyday dish too, known as tam mak hoong. For a properly Isan-style meal, think of three things together: sour som tam, sticky rice, and herb-marinated grilled chicken, kai yang (in Japanese).

On many restaurant menus outside Thailand it is simply called "papaya salad," but the real flavor is far more complex than the name suggests. The unapologetic heat of chiles, the bright sourness of lime, the deep sweetness of palm sugar, the briny saltiness of fish sauce, the savory depth of dried shrimp: all five tastes hit your tongue at once, and it is hard to forget the first time.

Ingredients (serves 2)

Instructions

Prep

Som tam cooks quickly, but careful prep makes the dish. Shredding the green papaya is the most important part.

First peel the papaya, halve it lengthwise and scoop out the seeds with a spoon. Next, make fine lengthwise cuts across the surface with the blade of a knife. Bangkok street vendors use a technique where they tap the surface of the papaya with a cleaver to score it, then slice off thin shreds.

If you are not used to that, slice the papaya about 2 mm thick first and then cut it into matchsticks. What matters is that the strips are uniformly thin; uneven strips take up the dressing unevenly.

Soak the shredded papaya in water for 5 minutes to crisp it up, then drain it thoroughly in a colander.

Cut the green beans raw into 4 cm pieces. In Thailand they are used raw. Beans grown elsewhere can be tougher, but the pounding step breaks down the fibers and makes them easier to eat. If they are still too tough, blanch them in hot water for just 30 seconds.

Types of Som Tam: Over 14 Variations

Outside Thailand it is often lumped together as "papaya salad," but there are more than 14 varieties of som tam in Thailand. If you do not specify which one you want when ordering, the vendor will ask, "Which som tam?"

Popular variations

Som tam Thai has a fish-sauce base and a mild profile. It is popular with visitors, and most som tam served in Thai restaurants abroad is this one. Som tam pla ra, on the other hand, is defined by the strong smell of fermented fish, and it is the one many people in Isan call "the real som tam." If you are new to som tam, start with the Thai version and work up to pla ra once you are used to it.

Tips: Mastering the Balance of Five Flavors

The essence of som tam is not how you pound but how you season. The fine-tuning of flavor, called prung rot (ปรุงรส) in Thai, is a skill street vendors have refined over decades.

The five-flavor balance

Som tam is made of five elements.

The most important balance is between sour and spicy. As the name som (sour) suggests, sourness is the star. Only when the sourness can stand up to the heat does it taste like the real thing.

At Thai street stalls you will be asked how spicy you want it. These are the common answers.

• Mai phet (not spicy): 0–1 chiles
• Phet nit noi (a little spicy): 2–3 chiles
• Phet mak (very spicy): 5 or more chiles
• Phet Thai (spicy the way Thai people eat it): 10 or more chiles. Not recommended for visitors

Pounding vs. mixing

The most common mistake in making som tam is pounding too much.

There are two motions with a mortar and pestle.

Pok (pound): bring the pestle straight down to crush the ingredients. You use it at the first step to make the garlic and chiles into a paste.

Once the green papaya is in, repeated "pok" will crush it into mush. The charm of som tam is its crisp texture, so after adding the papaya, concentrate on "khluk," the tossing motion, and limit the pok to 2–3 times.

When You Cannot Find Green Papaya: Substitute Guide

Green papaya can be hard to find at ordinary supermarkets. But the essence of som tam is not the papaya; it is the technique of pounding and tossing in seasoning. Even with a substitute, as long as the five flavors are in balance, you can make a very good som tam.

Comparing substitutes

Daikon is the easiest to find and the one I recommend. Peel it, shred it into matchsticks, soak it in water for 5 minutes, and drain. It is a bit softer than papaya, so pound 1–2 times fewer.

In northeastern Thailand, versions that use cucumber (som tam tang kwa) or corn (som tam khao phot) instead of green papaya are common, so there is no need to stick to papaya.

Using a Mortar and Pestle (Khrok and Sak)

Why use a mortar?

Why pound rather than use a knife or bowl? There are three reasons.

1. It breaks the fibers. A knife only cuts the fibers, while a pestle crushes and tears them. That changes how the flavor gets in. Pounded green papaya soaks up the seasoning through its tiny tears, so every piece is flavored.

2. It maximizes the aroma of garlic and chiles. The allicin in garlic and the capsaicin in chiles are released when cells are physically broken. Pounding breaks more cell surface than slicing, which gives a stronger flavor.

3. You can pound and toss at the same time. The deep shape of the mortar is suited to the "pok-khluk" motion of pounding and mixing in one go. In a bowl the liquid would spill, but the tall walls of a mortar keep it in.

Alternatives to a Thai clay mortar

A Thai clay mortar can be hard to find outside Southeast Asia, but these substitutes work.

If you make som tam often, a Thai clay mortar is a worthwhile investment, and Southeast Asian grocery stores and online sellers carry them.

History: A World-Famous Healthy Dish Born of Isan's Hardship

To talk about the origins of som tam you need to know the history of Isan in northeastern Thailand.

Isan covers 20 of Thailand's 76 provinces, a vast plateau, and historically it has been the poorest region of the country. The laterite soil of the Mekong basin is poorly suited to rice farming, the difference between rainy and dry seasons is severe, and securing water has always been a challenge. In this harsh environment, people honed the wisdom of using every ingredient without waste.

Green papaya is a hardy fruit that bears all year in the tropics. Harvested while still "green," before it ripens, it can be used as a vegetable, and since fruit keeps coming it was cheap. In Isan villages it was everyday food: pick papaya from the yard, pound it in a mortar, season it with chiles from the field and fish sauce, and eat it with sticky rice.

From the 1960s, large numbers of Isan people migrated to Bangkok for work. People from Isan working on construction sites and as taxi drivers began selling the flavors of home on Bangkok's streets, and that is what spread som tam across the country. At first it was looked down on as "country food," but its explosive flavor won over city dwellers, and by the 1980s it had become a representative dish of Bangkok street-food culture.

In 2011, in a ranking of the world's most delicious foods run by CNN's travel site, som tam came in at number 46. Another Thai dish, pad Thai (in Japanese), ranked fifth.

Isan cooking is defined by techniques for drawing the maximum flavor from limited ingredients. Fermented fish (pla ra), fermented sausage (sai krok Isan) and insect dishes (jing mut) all grew out of the wisdom of preserving food and amplifying flavor. Som tam is likewise a "flavor amplifier" that packs all five tastes into one inexpensive ingredient, green papaya. It shares a spirit with Senegal's thieboudienne (in Japanese) and Brazil's feijoada: great food cultures born from poverty.

Perfect Partner: Sticky Rice (Khao Niao)

No discussion of som tam is complete without its partner, khao niao (ข้าวเหนียว), Thai-style sticky rice. In Isan, sticky rice is more common as the staple than jasmine rice, and it is served in a bamboo basket (tip khao).

The Isan way is to tear off a piece of sticky rice by hand, roll it into a ball, and dip it in the juices of the som tam. It acts as a cushion for the heat of the salad and gently wraps a mouth made raw by capsaicin.

How to cook khao niao

1. Wash the sticky rice and soak it in plenty of water for at least 4 hours (overnight is best).
2. Drain, line a steamer with parchment paper, and spread the rice over it.
3. Steam over high heat for 20–25 minutes, turning the rice over halfway so it cooks evenly.
4. When done, loosen gently with a rice paddle and keep warm in a lidded container.

Storage and Shelf Life

Som tam is a dish to eat right after making it. After 30 minutes the papaya releases water, the flavor gets muddy and the texture goes limp. This quick deterioration is why Bangkok street vendors make each plate to order.

For a shortcut, keep shredded green papaya in the refrigerator and pound and toss it just before eating. If you mix the dressing ahead of time, the actual cooking time comes to within 5 minutes.

Nutrition and Health

Som tam is low in calories (around 220 kcal) but rich in vitamin C, fiber and potassium. It uses almost no oil and no cooking, so nutrient loss is minimal.

Green papaya contains the enzyme papain, which helps break down protein. That is a sensible reason Thai meals pair som tam with meat dishes such as gapao rice (in Japanese) and grilled pork neck (kor moo yang).

Capsaicin has been studied for small effects on metabolism, but it can also irritate the stomach lining, so if you have a sensitive stomach, go easy on the chiles. Other Southeast Asian dishes offer different benefits too, such as the coconut milk of nasi lemak (in Japanese) and the tamarind sauce of pad Thai (in Japanese). Among them, som tam is the lowest in calories and one of the highest in vegetables.

Variations: Making Som Tam the Star of the Table

Som tam noodles (som tam meets noodles)

A fusion dish popular in Bangkok in recent years tosses noodles in som tam dressing. Boil rice noodles (sen lek), cool them in cold water, and toss with the dressing. As the exact opposite of the stir-fried pad Thai (in Japanese), it is a cold noodle dish that is especially popular in summer.

It also works with Japanese somen or hiyamugi: use the fish sauce, lime and chile dressing in place of the usual dipping sauce and ordinary noodles turn into an ethnic dish in an instant.

Som tam tacos

Fill Mexican taco shells with som tam and serve with cilantro and lime. This fusion taco is a popular street food at Bangkok night markets, and the sourness and heat of the salad cut through the richness of the taco. Wrapping it in empanada (in Japanese) dough and frying is another interesting twist.

Japanese-style som tam with daikon

The most approachable variation for Japanese home kitchens is a shredded-daikon som tam with myoga and shiso added as aromatics. Adding 1 tbsp of ponzu in place of the fish sauce stays close to Japanese tastes while keeping the refreshing quality of som tam. It is ideal as a side for grilled fish or fried chicken, and also pairs well with strongly flavored dishes such as adobo (in Japanese).

Som tam salad bowl

A good option if you are watching your diet is a salad bowl built on som tam. Add grilled chicken, avocado and quinoa to shredded green papaya (or daikon) and dress with the som tam dressing. It becomes a one-bowl meal with a good balance of protein, healthy fats and fiber. At about 400 kcal it is satisfying as lunch. If you use the chicken from shawarma (in Japanese) in place of grilled chicken, you get a Middle East meets Thailand fusion bowl.

Ingredient Guide: Sourcing Som Tam Ingredients

Choosing fish sauce

If you are unsure, start with Megachef. Tiparos, the brand most often seen in Asian grocery aisles, is also perfectly good.

Substitutes for prik kee noo (bird's eye chiles)

The prik kee noo (พริกขี้หนู) used in authentic som tam is 3–5 times hotter than Japanese takanotsume chiles. If you cannot find them, these substitutes work.

Shima togarashi comes closest. You can find it at shops that carry Okinawan ingredients and online.

Frequently Asked Questions

Q. Where can I buy green papaya?

Asian grocery stores are the most reliable source, and you can often order it online. If you cannot find it, shredded daikon is the closest substitute.

Q. It is too hot for me. How can I tone it down?

Use just one chile, or remove the seeds, and the heat is roughly halved. If it has already become too hot, add more green papaya to dilute it, or eat it with sticky rice or cabbage. Milk and yogurt also help neutralize the burn of capsaicin.

Q. I do not have a mortar. Can I still make it?

Yes. Put the ingredients in a sturdy plastic bag and pound with a rolling pin. Or put them in a large bowl and pound with the end of a pestle. Do not use a food processor, since it will pulverize the green papaya.

Q. Can I make som tam ahead?

Unfortunately it is not well suited to that. After 30 minutes the water comes out and the texture suffers. The best approach is to store shredded papaya and the dressing mix separately and toss them together just before eating.

Q. Can children eat it?

Leave out the chiles entirely and use a little more palm sugar for a mild version children can eat. In Thailand a zero-heat version, "som tam mai phet," is often made for children.

Related Articles

For more Thai classics, try pad Thai (in Japanese) and gapao rice (in Japanese). Pad Thai is a stir-fried noodle dish and gapao is a basil stir-fry over rice, two very different approaches from som tam. It is also fun to compare the national dishes of other Southeast Asian countries, such as Vietnam's banh mi (in Japanese) and Indonesia's nasi goreng (in Japanese). Malaysia's nasi lemak (in Japanese) and the Philippines' adobo (in Japanese) are good gateways to the region's diversity.

If you are curious about Middle Eastern appetizers, hummus (in Japanese) and tabbouleh share som tam's spirit of a light, vegetable-centered dish. Som tam also goes well as a side with shawarma (in Japanese). An overview of Middle Eastern cuisine (in Japanese) covers meze culture in depth.

African cuisine has its own salad traditions too, and Senegal's thieboudienne (in Japanese) is served with a fresh salad. An overview of South American cuisine (in Japanese) covers dishes that use raw vegetables and raw fish, such as Peru's ceviche (in Japanese).

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