Travel the world and ask any seasoned diner which country it was that invented tom yam kung, and you’ll be told that it is a Thai dish. There are many other tom yam dishes made with ingredients like fish, crispy dried fish, mushrooms and pork leg, but it is the version made with shrimp that represents the dish in its most perfect form.

For Thais, shrimps are among the most delicious of foods. Doctors may warn that they are full of cholesterol, but this is a thought that is suppressed easily enough when seated in front of a platterful of giant grilled prawns accompanied by a spicy dipping sauce to bring out the best in them. In Thailand, gourmets are lucky to have a variety of freshwater and saltwater shrimps and prawns to choose from that are made into many different kinds of dishes.

Freshwater prawns are primarily macrobrachium rosenbergii. Large ones weighing half a kilogramme or more were traditionally known in Thai as kung luang – a term that indicated their rank as the king of prawns. There were other terms for the smaller ones, all of which was useful to buyers and sellers as indications of size. Today this terminology has somewhat fallen out of use, with prawns of every size called simply kung mae nam, or river prawns.

Another fresh water species is the kung foy, a tiny animal that doesn’t grow beyond a centimetre in length. It occurs naturally in ponds and marshes.

The qualities that give river prawns their reputation as the best of the best are their firm meat and delicate flavour with no fishy odour. The head is filled with the orange prawn fat that is highly esteemed in Thai cuisine for its delectable flavour. Its aroma is said to have a stimulating effect on the appetite.

In addition to its value as food, the river prawn is a reliable indicator of the quality of natural water sources. It will only thrive in clean water.

When the female is ready to lay her eggs, she swims to the mouth of the river where the water is brackish and deposits them there. The young hatch and remain at the river mouth, feeding on plankton until they are big enough to swim back upstream. They eat along the way, growing constantly, and the farther they swim, the bigger they get.

In the past, some of the largest prawns were caught a full 200 kilometres from the mouth of the river. This proves that if a river is clean and the water well oxygenated, its pristine quality will be reflected in the distribution and size of its prawns.

But the human appetite for river prawns is much bigger than rivers can satisfy naturally, and shrimp farms with ponds have come into being to fill the gap. Farm-raised prawns are of medium size, between 100 and 150 grams, with none reaching the jumbo size of fully mature river specimens.

It would take a pond-raised prawn at least two years to reach full size, and farmers are burdened with high maintenance costs. If they wait for the prawns to reach giant size, the return would not be high enough to justify the extra expenditure. There is also the risk of their dying before reaching maturity.

The sea rather than the river is the source of two other popular types, the white shrimp, called chae buay, and the Black Tiger Prawn. Like the river shrimp, their meat has an appetisingly solid texture and delicious flavour, but the heads contain very little fat.

Originally, all of these ocean shrimp and prawns were caught by fishermen, but once again the demand came to exceed the supply, especially as the seafood export industry developed. As with these river prawns, farms were set up to make up the difference.

The farmers use two methods. The first of these relies on nature. Seawater is allowed to flow into the ponds, introducing young sea creatures of all kinds. The farmer simply allows them to grow naturally with larger creatures eating smaller ones, crabs eating baby shellfish, and fish making a meal of baby shrimp and crabs. The larger shrimp fed on tiny fish and crabs and grew to saleable sizes.

When the time came to take his produce to the market, the owner of the ponds would have many kinds of seafood to sell at different prices. Although this farming method is effective, it requires large ponds covering a wide area and a large investment in time before the shrimp, fish, and crabs grow big enough to sell.

The second approach is to focus only on prawns, usually the Black Tiger Prawn. Eggs are collected from special breeding ponds and hatched. The new babies are then released into other ponds where they are raised very carefully. Black tiger prawns are extremely sensitive to water purity and the quality of the food they are given. Farmers can calculate the length of time it will take the prawns to reach a given size. Those who have mastered this technique can become very successful because prawns are established as a valuable export.

With such a variety of choice shrimp and prawns thriving in the country’s natural waters and farms, it isn’t surprising that Thai cooks have devised a brilliant repertoire of dishes to highlight the special qualities of each type. One of the simplest of them is kung phao, or grilled prawns. Jumbo river prawns are especially delicious when roasted over charcoal, but the cook has to have a sharp sense of timing when setting them on the grill.

If the whole prawns spend too much time over the fire, the meat becomes tough and rubbery. They are at their best at the moment when the heat turns the meat white, and is still soft and juicy. This means that grilling prawns is not as simple as it looks. The cook must have an expert’s ability to judge how hot the fire should be to cook prawns of a given size properly, and exactly how long they should stay on the fire.

After they are cooked, the prawns are cut lengthwise, and here again the cook has to make sure that the fat in the heads doesn’t come spilling out. The person eating the prawn also has to know what to do. The sack of body waste also found in the head must be removed and set aside.

No serving of grilled prawns is complete without a small bowl of dipping sauce. The best kind is the mixture that Thais often serve with seafood, a potent combination of salty fish sauce, lime juice and fiery chopped bird chillies.

Big river prawns are also excellent when prepared as kung thawt krathiem phrik Thai, fried with garlic and pepper. The garlic and peppercorns are pounded together in advance with some salt mixed in, and then mixed with the raw, shelled prawns until they are thoroughly covered. Here, again it is important to make sure that the fat contained in the heads doesn’t leak out.

When frying, the meat becomes firm but tender while the fat from the heads mixes with the frying oil to form a thick, yellow-orange liquid. True aficionados consider this fat to be the choicest part of the prawn. Spooned over hot rice it is incredibly delicious, and if some dipping sauce is added it is even better.

	Tom yam kung, the most internationally famous of Thai shrimp dishes, has the fragrance of the herbs cooked into it – galangal, lemon grass and kaffir lime leaf. Its superb flavour combines the sourness of lime, saltiness from fish sauce, and the spicy bite of bird chillies with the delicate flavour of fresh shrimp. A special accent is imparted to the taste by the thin layer of shrimp fat that floats on the surface. The best versions of this dish are always made with river prawns.
	Phlaa kung, on the other hand, is best when made with large sea prawns. They are grilled until the meat begins to turn white, then shelled, set on a platter, and doused with lime juice. The acid in the juice has the effect of cooking them further. Chopped bird chillies, fish sauce and mint leaves are sprinkled on top before serving. This recipe for phlaa kung is the one generally used now. In the past there was another dish, very similar to it, called yam kung, that was seasoned with roasted, dried chillies, grilled shallots, and grilled garlic that had been pounded in a mortar together with fermented shrimp paste.

Large sea prawns were grilled until partially cooked and then shelled and tossed with the pounded seasonings. Slivered Kaffir lime leaves, a small dash of lime juice and fish sauce were also put in, and then the prawns were set on a platter. A sour, olive-like fruit called makawk in Thai, was chopped and sprinkled on top together with some fresh coriander. The reason that the use of lime juice was kept to a minimum was to enable the special sourness of the makawk to assert itself. It can be seen that this traditional dish was more elaborate than today’s phlaa kung.

In addition to these grilled dishes, spicy salads and sour-hot soups, there are also a number of spicy cooked dishes made with shrimps and prawns. Choochee kung uses sea prawns since, like shrimp curries, it doesn't benefit from the fat found in fresh-water species. To make the choochee sauce, dried chillies, galangal, lemon grass, kaffir lime zest, shallots, garlic, and fermented shrimp paste are pounded together to a fine consistency, then fried in coconut cream until the mixture becomes very thick. Then palm sugar and fish sauce are added to taste.

When the sauce is ready, shelled, raw prawns are added and briefly fried in it. Then they are set on a platter and sprinkled with finely slivered Kaffir lime leaf.

The ingredients used to make prawn curry are only a little different from the makings for the choochee dish. Dried chillies, galangal, lemon grass, kaffir lime zest, fresh coriander root, pepper, and fermented shrimp paste are pounded together and fried in coconut cream, although not to the thick consistency needed for the choochee. Palm sugar and fish sauce are added to adjust the taste, and finally shelled fresh prawns are put in. Once again, sliced Kaffir lime leaves are sprinkled for fragrance.

Thawt man kung is another spicy shrimp or prawn dish that is made using a curry paste. Dried chillies, galangal, lemon grass, Kaffir lime zest, shallots, garlic, fresh coriander and salt are pounded together, then chopped, peeled shrimp are put in and pounded together with the mixture to form a thick paste. Ground coconut, rice flour, salt and chopped wing beans are mixed in and then the paste is formed into small patties and deep-fried in plenty of very hot oil. The fried fish patties are eaten with a dipping sauce made from chopped cucumbers, shallots, chillies, and coarsely pounded roasted peanuts in a salted vinegar.

Besides these spicy cooked shrimp and prawn dishes, there are some very tasty ones that don’t come on so aggressively. Khai toon is a custard-like dish made by putting layers of minced pork and fresh shrimp, pepper, coriander root, and salt into a small bowl or cup with a mixture of beaten egg and water. The chopped ingredients sink to the bottom, and the cup is steamed until the egg solidifies.

Shrimp are very popular in khao tom, or rice soup. This night-time favourite gets its flavour from aromatic herbs, ground pepper, and crisp-fried garlic in oil.

All of these dishes are made with large freshwater and saltwater shrimp and prawns. None of the ones mentioned so far call for the tiny kung foy mentioned earlier, but these, too have their place in the repertoire. The crunchy snack called kung thawt is made by pounding together galangal, lemon grass, shallots, garlic and kaffir lime zest to make a paste and then making a thin batter of rice flour, water, ground coconut and salt. Kung foy and the pounded seasonings are mixed into the batter, which is then spooned into a pan of hot oil to make crispy patties. Dipping sauce – the same one served with thawt man kung – adds the finishing touch.

The native Thai genius that created one of the world’s greatest and most varied cuisines did not stint in discovering ways to coax the best qualities out of the country’s wealth of shrimps and prawns. This claim can be easily tested by sampling any of the dishes described above.

ABOUT THE AUTHOR
Suthon Sukphisit
A former staff member of the Bangkok Post Outlook section, Suthon Sukphisit has written articles on Thailand’s art and culture and on topics related to Thai society, history, archaeology, architecture, environment and education. He now spends his leisure time pursuing another topic in which he is well-versed: food and cuisine.