What is tom yum?

Tom means boiled, yum stands for something dressed hot and sour, and hed means mushroom. In Thailand, tom yum is most often cooked with shrimp as tom yum goong. The mushroom version gets by with vegetable broth and is lighter. There is a clear version, tom yum nam sai, and a creamy one with coconut or evaporated milk and chili paste, tom yum nam khon. This recipe is the clear one.

The aromatics: lemongrass, galangal, lime leaves

Cut the lemongrass on the diagonal into 3 cm pieces and bruise them with the back of the knife so they release their aroma into the broth. Tear the makrut lime leaves and remove the hard center rib. Crush the chilies with the flat of the blade.

In Thai cooking, galangal also belongs in the soup. If you can get it, put 4 to 5 thin slices in the pot with the lemongrass. Ginger tastes hotter and less resinous, so it works as a substitute only in a small amount. In Thailand, lemongrass, galangal and leaves are not eaten. They stay in the bowl.

Mushrooms for tom yum

In Thailand, straw mushrooms or oyster mushrooms usually go into the pot. Here you can get straw mushrooms canned at an Asian grocery store. Tear oyster mushrooms into strips and halve button mushrooms. For fresh shiitake, cut off the hard stems, and soak dried ones first, with more under how to prepare shiitake. A mix of two kinds gives the bowl different textures.

Tom yum paste and the vegan version

With tom yum paste from a jar you skip part of the fresh herbs. Stir 2 to 3 tbsp into the boiling broth and taste afterwards with lime juice, because the pastes often taste sweeter and saltier than the fresh soup. Many pastes contain dried shrimp or fish sauce. For a vegan soup, read the ingredient list and replace the fish sauce from the recipe card with 2 tbsp light soy sauce.

Common mistakes

• Lime juice boiled: In a boiling pot the juice loses its freshness and tastes bitter. Stir it in after you take the pot off the heat.
• Mushrooms cooked too long: Oyster mushrooms go limp in 10 minutes. Add them to the firmer button mushrooms only after 5 minutes.
• Not tasted: Taste before serving. If it lacks salt, add fish sauce, if it lacks acidity, lime juice. If the soup is too sour, balance it with a pinch of sugar.

Tom yum ramen and other variations

For tom yum ramen, cook 80 g ramen or mie noodles per person in a separate pot and pour the hot soup over them. Rice noodles work too. With 200 ml coconut milk the soup turns creamy and comes close to tom kha gai. If you like the flavors without the broth, fry them with rice in a wok as khao pad tom yum.