Tom yum

Preparation

The taste of tom yum is based on sour and spicy flavors. A paste called nam prik pao is prepared as a base of the soup, to which water, herbs and meat are added. The nam prik pao is made from roasted chilies, shallots, and garlic and the ingredients are best grilled on a charcoal fire.

The basic ingredient of tom yum is shrimp or pork. The most popular tom yum base is river shrimp called tom yum goong.

The essential ingredients of tom yum are herbs such as lemongrass, galangal, and kaffir lime leaves. Other ingredients are also important, especially Thai chilies, mushroom, coriander leaf (cilantro), tomatoes, sweet white onions, lime juice, sugar, and fish sauce. Tom yum nam khon is a variety with coconut milk or evaporated milk.

Selected types

• Tom yam nam sai (Thai: ต้มยำน้ำใส), clear broth tom yam soup
• Tom yam nam khon (Thai: ต้มยำน้ำข้น) is a more recent variation from the 1980s. common with prawns as a main ingredient, evaporated milk or non-dairy creamer powder is added to the broth as a finishing touch.
• Tom yam kathi (Thai: ต้มยำกะทิ) – coconut milk-based tom yum—this is often confused with tom kha kai ("chicken galanga soup"), where galangal is the dominant flavour of the coconut milk-based soup.
• tom yam kung (Thai: ต้มยำกุ้ง) – the version of the dish most popular among tourists, is made with prawns as the main ingredient. The dish originated during the Rattanakosin Kingdom.
• Tom yam bhla (Thai: ต้มยำปลา) is a clear fish soup that was traditionally eaten with rice. It used to be the most widespread form of tom yam before mass-tourism came to Thailand, for fresh fish is readily available almost everywhere in the region's rivers, canals and lakes as well as in the sea. Usually fish with firm flesh that doesn't crumble after boiling is preferred for this type of soup.
• Tom yam gai (Thai: ต้มยำไก่) is the chicken version of the soup.
• Tom yam po taek (Thai: ต้มยำโป๊ะแตก) or tom yam thale (Thai: ต้มยำทะเล) is a variant of the soup with mixed seafood, like prawns, squid, clams and pieces of fish.
• Tom yam kung maphrao on nam khon (Thai: ต้มยำมะพร้าวอ่อนน้ำข้น), a version of prawn tom yum with the meat of a young coconut and a dash of (coconut) milk.
• Tom yam kha mu (Thai: ต้มยำขาหมู), made with pork leg. These require a long cooking time under low fire.

In the modern popularized versions the soup contains also mushrooms—usually straw mushrooms or oyster mushrooms. The soup is often topped with generous sprinkling of fresh chopped cilantro (coriander leaves). Sometimes Thai chili jam (nam phrik phao, Thai: น้ำพริกเผา) is added: this gives the soup a bright orange color and makes the chili flavor more pronounced.

Other spicy and sour soups

Less well known outside Thailand is tom khlong (ต้มโคล้ง), a spicy sour soup where the sourness, however, does not derive from lime juice but through the use of tamarind. Tom som (Thai: ต้มส้ม) are soups that are also very similar to tom yum but most often do not contain lemongrass or kaffir lime leaves. Depending on the type of tom som, the acidity can be derived from lime juice or from the use of tamarind.