If there is no salt in the water, it doesn't come from the sea. In the same way, if there is no kapi (fermented shrimp paste) in a meal that is being prepared, it probably isn't Thai. Kapi and Thai culinary traditions are tightly bound together.

Saltwater eels prepared as a ‘phat cha’

This doesn't mean that kapi is found only in Thailand. Many other countries also eat it  -  Malaysia, for example, where it is sold in firm sticks, and Southern China, especially Hainan, where liquid kapi is added to noodles.

It is thought that kapi came into being through a food preservation process. Small sea creatures were fermented, salted and dried so that they could be stored and eaten for a long time. It is made from a kind of small marine shrimp called khuy ta dam, of which there are two types. The first is very small, less than a centimetre in length, and lacks the long, sharp projections on the front of the head. The other kind is a little larger and does have the sharp spines. Both types have prominent black eyes.

Khuy ta dam live in areas where the shoreline is covered with dense swampy vegetation and mangrove thickets. This is because, right from the time they emerge from their eggs, they feed on the plankton that live along swampy shores. Other marine animals come to eat them, but they breed very quickly and replenish their numbers easily.

When making them into kapi they are mixed with salt with the ratio of 10 parts shrimp to one part salt. When the smaller type are used, after they are mixed with salt they are set in the sun, turning it from time to time so that the lower portion is also exposed to the sun. After three days it will have fermented into kapi.

Sea catfish coated with ‘kapi’ and deep fried as prepared at Keson

If the larger shrimp are used they are pounded first so that the hard spines on the head are pulverised. Then they are mixed with salt and set out in the sun to ferment for the same length of time as for kapi made with smaller shrimp. In some areas, this same technique is employed when the small shrimp are used.

The kapi made from the smaller khuy ta dam is considered to be superior. It has a smoother and softer consistency and better fragrance, as it contains more of the shrimp meat. But the residents of any place where kapi is made will claim that theirs is the best to be had.

What is it used for? Kapi goes into almost every kind of curry paste; even the non-spicy, vegetable soup-like kaeng lieng includes it. It is also an ingredient in most kinds of nam phrik. Sour fruit like unripe mangoes, mayom and maprang are dipped into kapi to cut their acid bite, and it is a component of many stir-fried dishes like koong phat sataw (made with shrimp and a crunchy, strong-smelling bean), phak boong phat kapi (a morning glory-like vine stir fried with kapi), and mu sam chan phat kapi (pork belly meat stir-fried with a pounded mixture of kapi, shallots, whole peppercorns, a little sugar and slivered tender lemon grass shoots).

‘Nam phrik kapi’ with ‘chakhram’ dipped in egg and fried.

Kapi is most popular in Thailand's Central Region and in the South. Even Muslim dishes made in the South like kaeng mussaman made with mutton contain it. It is also included in some Northern dishes, but is rarely eaten in Isan because cooks there use the fermented fish called pla ra, which has been part of the culinary culture there for many centuries. Kapi is thought to be less tasty.

It is odd that although kapi has never caught on in Isan, it is becoming increasingly popular in Laos, with its closely related culture and cuisine. Lao-style kui tio nuea, or beef noodles served with a variety of vegetables, is seasoned by younger Laos with kapi. Every shop that serves them will have a container of kapi on the table for customers to use.

The most famous kapi in Thailand comes from Khlong Khone, a small district in Samut Songkhram province. To get there, after crossing the bridge across the Mae Klong River (Phuttalertla Bridge) continue on for about five kilometres to the entrance to Wat Khao Yeesan. Go on for about 500 metres and there will be a turn-off to Tambon Khlong Khone.

It is located on a seashore where the bottom is muddy. It is different from shore areas in places like Bangkok or Samut Sakhon where the waves are strong and progressively erode away the shoreline. At Khlong Khone the beach extends further out into the sea each year. Locals report that the community temple, Wat Khlong Khone, has already been moved three times for new land that has appeared where there was once only water.

WATERWAYS: A view of the canal at Tambon Khlong Khone.

Khlong Khone has plenty of natural swamp vegetation and mangroves, and additional ones have been planted. They are alive with sea life that includes mussels, cockles, sea catfish, mackerel and other types. Especially important are the salt-water eels, which are difficult to find elsewhere.

Besides this high-quality seafood there are many tasty dishes that are available there, especially those made with the locally made kapi. The popular chilli dip called nam phrik kapi made in Khlong Khone contains no aubergine, only the sauce, and there is a delicious stir-fry made with squid and kapi. These two specialties alone make it an interesting place for foodies.

When visiting Khlong Khone, one food shop that is not to be missed is Keson, located in front of Wat Khlong Khone. It is a pleasant place, with the tables and chairs set along a khlong. On the menu are several delicious local dishes, among them are cockles served either briefly boiled or made into a yam, or sour-hot salad; nam phrik kapi kap pla thu thawt kap bai chakhram choop khao thawt (kapi-based chilli dip sauce served with fried mackerel and a local herb dipped in egg and fried); yam bai chakhram (a sour-hot salad made from the shoots of a seaside herb), phat cha pla duk thalay (a spicy stir-fry of sea catfish and herbs), and phat cha pla duk thalay (sea catfish coated with kapi and deep-fried). On days where the saltwater eels are available, have them prepared as a spicy, stir-fried phat cha.

Keson is open daily from morning until 9pm. In the evening the sound of the fishing boat motors as the fishermen return for the day can be pretty loud.

The phone number for Keson is 08-7036-0556.