Conjure up a mental list of old-fashioned dishes that still make the mouth water, and then notice how many include main ingredients that are dried or salted. Here's a personal selection: nuea khem tom kathi sai hawm daeng (salted beef stewed with shallots in coconut cream), nuea khem cheek pen sen foy phat kap namtaan (shredded salted dried beef stir-fried with palm sugar), plaa chon taak haeng khem tom kathi proong rote baeb tomyam sai bai makhaam awn (salted and dried snakehead fish stewed with sour-spicy seasonings in coconut cream with tender tamarind leaves), hua plaa chon taak haeng khem sai kathi sai fak (dried salted snakehead fish head stewed with coconut cream and squash), hoy malaeng phuu taak haeng khem phat kap nam taan (salted and dried mussels stir-fried with palm sugar or the same mussels simmered into a curry with pineapple). The list goes on.
Why is it that so many of these dishes call for fish or shellfish that have been salted and sun dried? One reason has to do with food preservation. In the times before refrigeration the main way of keeping these foods from spoiling was to salt them and then set them in the sun until they were completely dry. Folk knowledge amassed over the centuries told how much salt would be needed to preserve a given kind of meat, and how long each one should spend drying in the sun.
Even though we do have refrigerators and freezers now, we still need these salted and dried fish and meats, because the popularity of dishes that call for them remains strong even though the salt and sunshine are no longer necessary to keep main ingredients from going bad. Different techniques are used to do the salting and drying.
One of them is taak haeng daed dio, which involves rubbing the meat with salt (not too much) and sun-drying it for a short period of time, just a few hours if the sun is very strong. Pork, beef, snakehead fish, sheatfish and squid can all be dried using the daed dio method.
When preserving food to be stored for the longest possible period of time, there is a technique that does not require salt and gives the meat a special aroma. It can be used most easily with fish to produce the dried fish known as plaa krawp rom khwan -- crispy smoked fish.
This method works best with fish like sheatfish, plaa daeng, plaa nam nguen, plaa khao and others that do not have scales. Half a century ago, they were so abundant in Thailand's waters that people were often unable to eat an entire catch, and extras were made into plaa krawp rom khwan.
But there was a condition: it was not considered appropriate for families to dry the fish for their own use. The process was complicated and required so much time that there had to be a large number of fish to make it worthwhile. The usual method of salting and drying fish was much easier, and was suitable for preserving smaller quantities of them. If the family did want to eat crispy smoked fish, the best thing would be to buy some from someone who made it for sale. Even though it might be a bit expensive, purchasing the fish would be much more economical than making it at home.
The technique used by those who prepare the fish commercially today is still what it was in the past: gut the fish, then thread a number of them together by passing a bamboo rod through the gums of their mouths. A platform is made for the fish to be set out upon, arranged in attractive clusters, to dry in the sun for just one day, and then they are moved into a square room made of galvanised iron to be smoked.
Sawdust is the fuel for the smoking fires. The fish are smoked in the closed room for two or three days until completely dry. The reason the crispy smoked fish are so expensive is that 10 kilos of fresh fish will only yield two kilos of crispy dry ones.
Scaleless sheatfish are used is because of their flat, blade-like shape. The heat from the fire can easily penetrate them completely, so that when the smoking and drying is finished, there is still quite a lot of meat left on them. What's more, they are a tasty fish that has few bones, just a long one running along the back that is not very hard.
Even though we have enough of these fish to smoke dry here in Thailand to satisfy demand by those who like it, the kind that real aficionados like most is the plaa krawp rom khwan from Cambodia. They prefer it because it is less expensive, and the sheatfish used to make it are bigger than those used here.
Crisp-dried fish from Cambodia were not always easy to get hold of, however. There was a period of half a century when relations between the two countries were severed. The fish had to be smuggled in at the border at Aranyaprathet, and since roads in Cambodia were in poor condition, it took a long time for them to travel from the places where they were produced to the border area. This meant that by the time they got there, they were quite old, and sometimes infested with insects. Thais who obtained the dried fish had to steam or boil them to clean them before use. Nowadays, however, this is no longer a problem.
These days, crispy smoked fish made in Thailand from sheatfish and other scaleless fish are small and less plentiful than they once were. The main sources for them are the Uthai Thani area, because of its proximity to the Chao Phraya and Sakaekrang rivers, as well as Sing Buri, Suphan Buri, Ang Thong and Ayutthaya, where the scaleless fish used are usually snakehead, catfish, plaa kot and plaa khang.
Smaller fish are also prepared this way in Ban Pong and Photharam districts in Ratchaburi along the banks of the Mae Klong River. The fish used is plaa soy noke khao, which looks like a carp but is smaller and similarly full of bones. They are not popular with buyers.
Given the fact that crispy smoked fish are widely popular and have been so for a long time, it is odd that you almost never find them in supermarkets or even in fresh markets. If they do appear, it is usually in small quantities. One reason for this might be their high price, something that also might explain the rarity of dishes made with them on restaurant menus.
Some of the dishes in which they are at their best are the soup called tom kloang (a type of tom yam); kaeng lieng, for which the seasoning paste is made by pounding crispy smoked fish with pepper, shallots and kapi; and nam phrik plaa krawp, which is made by taking dried chillies, shallots, garlic and roasted kapi and pounding them with the dried fish, then adding sour tamarind pulp, palm sugar and nam plaa. This nam phrik has a pasty consistency and can be kept for long periods of time.
Crispy smoked fish can still be found at markets in riverside provinces. If you do happen on some, don't waste time deliberating about whether or not to make a purchase. Pounce, because back at home you can find many delicious recipes for preparing them, and the fish can be stored indefinitely in the refrigerator, ready to be recruited for the table whenever the craving strikes for a tom kloang, yam plaa krawp or another of the delectable dishes that can't be made without them.
