Thua Nao is an indigenous fermented soybean product. It originates from the Shan people residing in the north-western areas of Thailand, and thus is widely available and commonly used in Northern Thailand. It is usually sold at markets in small packs of thin disks at approximately 10 – 12 cm. in diameter.
There are two main types of Thua Nao:
- Fresh (Thua Nao muh/Thua Nao bpuh)
- Dry (Thua Nao khaaep)
How is Thua Nao made?
In Thai, “Thua” means soybean and “Nao”, spoiled. The process can vary a bit depending on the geographic area, but in general, there are four main steps in the manufacturing process: soaking, boiling, fermenting and drying.
First, the soybeans are washed and soaked until fully expanded, then boiled in brine until they are soft. After being cooked, the beans are pounded lightly in a wooden mortar to break them up a bit, then wrapped in banana or dry fern leaves, placed in a basket, and left to ferment in ambient temperature (in Thailand between 25 – 30 degrees of celcius) by naturally occurring bacillus and microflora. After about 2 – 3 days, mature Thua Nao will look molded or slimy with a white or yellowish color and have a rancid smell. The beans are pounded again in the mortar to form a smooth paste. At this point salt and sometimes ground dried chilies are added.
If making fresh Thua Nao, the only thing left to do is to grill the cakes over open fire wrapped in a banana leaf. If making the dry version, the disks are formed by spreading 1 – 2 tbsp of bean mixture onto a large leaf, covering it with another leaf and pressing them slightly together. The disks are left to dry in the sun for about 3 days. When peeling off the leaves, the result will be a thin sheet of fermented soybeans.
How to store Thua Nao:
Fresh Thua Nao has a short durability, whereas the dry version can store for several months. It doesn’t smell very good (some minorities refer to it as “bad odor beans”), so it is best to store it in an airtight container.
Thua Nao substitutes:
There are similar products from other countries that can be used as substitutes: natto or miso from Japan, kinema from India, or doenjang from Korea.
How do you use Thua Nao?
It is generally regarded as a protein supplement and can be eaten raw or as a condiment mixed with chilies, onions, and salt. But it is more often used as an ingredient similar to shrimp paste kapi.
Before using Thua Nao as a cooking ingredient, the cakes are lightly roasted. It can be done over an open fire, in the oven, or on a dry pan. The heat increases crispness and enhances the flavor. The cakes are then either broken up into smaller pieces or pounded to a fine powder. I mostly just use the broken up pieces. If added to soups, it will dissolve in the liquid, and as part of curry pastes, thorough pounding will help it blend with the other ingredients.
In the picture to the right, you can see roasted Thua Nao on the left and dry Thua Nao on the right. The darker bottom versions have chilies inside.
Recipes using Thua Nao: