Pla Ra (Thai: ปลาร้า, pronounced [plāː ráː]), is fermented fish. It is the traditional way, Thais in central provinces and the northeast (Isan province) are eating fish and rice. In these rather poor provinces, there is only one rice growing cycle every year. The planting season starts in May and by the end of June, this season is over. After planting, the rice fields are stocked with fish fingerlings. The growing season follows from July to November, and rice and fish are harvested in December.
Rice can be dried and stored easily, whereas fish have to be preserved. Farmers converted all suitable land into rice farming. Therefore, there was only restricted space left for fish, which could be caught wild and outside the rice farming cycle. Therefore, fish preservation was necessary. And best are either strong-smelling or -tasting fish products, where a small amount could flavor lots of rice. This led to the production of fish sauce and fermented fish, of Pla Ra.
Which fish species are used for preparing Pla Ra?
Fish species used for making Pla Ra differ from the location. In Central provinces, mainly Walking catfish (Clarias batrachus; Pla Sawai) or Stripped snakehead (Channa striata; Pla Chon) are used. They will be mixed with roasted broken rice or rice powder. In North-East provinces, Giant Gourami, Mud carp, Nile tilapia, and other fish with white and soft meat are used. In these areas together with rice bran. There is also a third general type of Pla R. This is Pla Ra Sot (Fresh Pla Ra), which uses small white meat fish together with cooked rice or rice bran. The fermenting time of Pla Ra Sot is only for some weeks.
Different types of Pla Ra
There are at least three different types of Pla Ra sauce produced in Thailand. Pla Ra with snakehead from the Central provinces is yellow with soft fish meat and a less intensive smell. Pla Ra with Giant Gourami from Isan is often dark with an intense smell. Pla Ra Sot is salty with a bit of sour taste from lactic acid. There are also a variety of fermented fish sauces with chilies now on the market, which are produced industrially.
How to produce Pla Ra in Isan province
In order not to confuse the different types of Pla Ra, we will only describe typical Pla Ra production in the Isan area.
As mentioned earlier before, white meat fish (Giant Gourami, mud carp, Tilapia, and others) of various sizes will be used. They are on average between 15 and 30 cm long and will be washed, descaled and all fins removed. Thereafter the head will be cut off behind the gill cover and the fish be gutted. Afterward, the fish body is cut into 10 cm wide chunks. The inner body cavities of these fish chunks have to be cleaned. This has to be done in such a way, that no kidney parts remain around the spine. And – all dark skin inside the cavity is completely removed. The kidney and its parts and dark skin will give an unpleasant smell after fermentation.
After proper cleaning, the fish parts are mixed with lots of rock salt, which was crushed in a mortar before. These salted chunks are now pressed by hand so that water can rinse off, and stacked in an earthen pot. They should be compressed by hand so that they are tightly stacked. All remaining rock salt and brine are put onto the fish stack until it is completely covered. This pot is left in an open, shady place, just covered by an earthen lid.
Further processing and fermentation
About one week later, all fish pieces are removed from the pot. They are slightly pressed by hand and the pot is cleaned with water. Then, they are salted again and liberally dusted with rice bran, which improves fermentation and adds the typical aroma. The pot is covered again and left alone for such a time as the farmer finds fit for his taste.
The minimum fermentation time is one week for light aromas preferred by restaurants. But this can be extended to up to one year for a strong smell. Such dark Pla Ra sauce is the right choice for the hard-sotten fermented fish connoisseur. A fermentation period between 3-5 months is preferred by most Pla Ra makers.
But for such a period, the bacteria content is the highest. Which means, the sauce is quite lively. Pla Ra therefore should always be heated above cooking temperature to kill off these microorganisms. Halophilic bacteria will play an important role in the taste and aroma of the sauce. If Pla Ra is used uncooked in food, this food can easily be contaminated by various bacteria.
Lessons learned from Pla Ra
- Traditional wet preservation methods of fish in tropical countries were once necessary for the well-being of the population.
- Nowadays they are replaced by preservation methods, which are often combinations of mechanical and chemical methods – and are tasting better.
- Many local people in upcountry provinces of Thailand are still addicted to the taste and aroma of fermented fish. That’s best proof, that the concept of ‘acquired taste’ really works.
