Hot and sour soup is a variety of soups from several Asian culinary traditions. In all cases, the soup contains ingredients to make it both spicy and sour.
"Hot and sour soup" is a Chinese soup claimed variously by the regional cuisines of Beijing and Sichuan as a regional dish. The Chinese hot and sour soup is usually meat-based, and often contains ingredients such as day lily buds, wood ear fungus, bamboo shoots, and tofu, in a broth that is sometimes flavored with pork blood. Sometimes, the soup would also have carrots and pieces of pork. It is typically made hot by red peppers or white pepper, and sour by vinegar.
Japan
In Japan, ramen noodles are usually added to hot and sour soup to make suratan-men or "hot and sour soup noodles".
South Asia
India
In India, this soup is made with red and green chillies, ginger, carrots, snow peas, tofu, soy sauce, rice vinegar and a pinch of sugar. It is viewed in India as being a Chinese soup.
Hot and sour soup is usually made in Pakistan with chicken, carrots, cabbage, corn flour, eggs, vinegar, chili, soya sauce and salt. It may also contain bean sprout and capsicum.
Samlor machu pkong or "Sour Shrimp Stew" is a Cambodian sour soup flavored with lemon, chilis, prawns and/or shrimp. One of the most popular sour soups in Cambodia, it is eaten most often on special occasions. Samlar machu yuan or "Vietnam sour soup" is another common hot and sour soup that originated in the Mekong Delta region. It is made with fish, usually mudfish, walking catfish or tilapia, that has first been fried or broiled then added to the broth. Chicken may also be substituted. The ingredients which give the stew its characteristic flavor may vary depending on what is available locally to the cook. Possible ingredients include various combinations of pineapple, tomato, ngo gai, fried garlic, papaya, lotus root, Thai basil and Thai chili.
There are numerous sour soup dishes in the Philippines using souring agents that range from tamarind to unripe mangoes, guavas, butterfly tree leaves, citruses, santol, bilimbi, gooseberry tree fruits, binukaw fruits, and libas fruits, among others. Most of these dishes are included in the umbrella termsinigang, but there are other regional dishes like sinampalukan, pinangat na isda, cansi, and linarang which are cooked slightly differently. The dishes are related to the paksiw class of dishes which are soured using vinegar.
Canh chua, a sour soup indigenous to the Mekong River region of southern Vietnam. It is typically made with fish from the Mekong River or shrimp, pineapple, tomatoes, and bean sprouts, and flavored with tamarind and the lemony-scented herb ngò ôm. When made in style of a hot pot, canh chua is called lẩu canh chua.