Later, people from Isaan brought the recipe along when they migrated to Bangkok for work during the reign of King Rama II in the late 1800s. In Bangkok, Som Tam was modified to contain palm sugar and other ingredients, which spawn many different variations.
The Isaan style is still considered by many to be the ‘real’ som tam, which features strips of papaya pounded with chilies, and then drizzled with fish sauce known as plaa raa. It also contains ingredients ranging from preserved freshwater crabs to ma kok, a tart fruit. The version more commonly recognised by city dwellers revolves around thinly sliced crispy papaya dressed with bottled fish sauce, tomatoes, green beans, roasted peanuts and dried shrimp.
The dish is sold in food markets across Thailand while also popular in countries like Cambodia, Laos, and Vietnam. A Som Tam meal is relatively light, and largely associated with street stalls and carts run by residents of northeast Thailand. Diners typically state to the vendors how much chilli and sugar they prefer before the ingredients are pounded with a mortar and pestle.
Som Tam can be mixed with a variety of ingredients such as preserved crab, peanuts, fresh crab, fresh snake beans, dried shrimps, preserved Gouramy fish or rice noodles. Marinated charcoal grilled chicken, fresh cabbage, snake beans, or grilled marinated catfish are also popular accompaniments to a Som Tam meal. Cucumbers, green mangoes, and snake beans can replace papaya as the main ingredient.