Stink Bean: A local delicacy with quite a smell

stunk beanWhile there are an abundance of herbs local to south Thailand, one in particular, popular both on its own and mixed with other ingredients, is called sato (or in English, “stink bean,” or parkia speciosa). Full of vitamins and minerals, the bean includes carbohydrates, calcium, phosphorus, iron, protein, vitamins B1, B2, and B3, and vitamin C—nutrients all vital for the body.

Sato is a medium to large sized perennial plant of the bean family, growing up to 30 meters tall. Its trunk, smooth and light brown in color, splinters into small fragments when peeled. The tree’s branchlets are finely haired. The leaves are “bipinnately compound” (in botany terms), meaning that each leaf branch has approximately 14-18 pairs of leaflet compounds, with each leaflet compound composed of approximately 31-38 pairs of leaves. These leaves, asymmetric in shape, have a rounded tip and a small lobe at the base. The flowers bloom in clusters, tightly packed together as one mass, hanging like chandeliers throughout the whole tree. Each flower has both a stem and a ring of leaves adorning its base.

Sato can be found throughout Thailand’s wet rainforests, growing in sandy clay soil either on hills or on flatlands. It’s often planted in the provinces of Surat Thani and Nakhon Si Thammarat.

The flowers bloom first during April, and remain on the tree for around 70 days. The primary produce of the sato is its flat seed pods, which are about 4 centimeters in width and 35-45 centimeters in length. The seeds or beans inside are oval in shape, almost circular, and are arranged perpendicular to the length of the seed pod. Light green in color, they can be eaten, though their smell is notoriously foul.

Despite its rank odor, people still enjoy eating sato all the same, especially in the south of Thailand. While both the beans and leaves are edible, the beans are more popular. They are often eaten as “side veggies,” (in Thai, pak nor). The Thai concept of “side veggies” is much like the Western idea of “chips and dip.” The vegetables, in this case sato, are dipped in chili sauce (nam prik), spicy curries (gang phet), coconut milk curry (gang gati), or sour tamarind paste soup (gang som). When consumed this way, the beans are eaten fresh with or without their shells, yielding a fatty, rich flavor. Some prefer however to modify the beans a bit, through pickling, boiling, or roasting them whole, pod in all, over a fire (a dish called to mok). Other than their use as “side veggies,” the beans are also consumed as part of a larger dish, such as in a spicy stir fry, stir fried with coconut milk and shrimp, or boiled in coconut milk.

According to traditional Thai treatises, sato can also be used as an herbal medicine to treat flatulence, urinary issues (including cloudy or bloody urine), kidney dysfunction, indigestion, or lack of appetite. Traditional Thai doctors also believe that sato canhelp lower levels of blood sugar, so that those who ingest it regularly have a lower risk of diabetes.