It is known for its complex interplay of at least three and up to four or five fundamental taste senses in each dish or the overall meal: sour, sweet, salty, bitter and spicy. They were introduced to Thailand by the Hokkien people starting in the 15th century, and by the Teochew people who started settling in larger numbers from the late 18th century CE onward, mainly in the towns and cities, and now form the majority of the Thai Chinese. Such dishes include chok Thai: โจ๊ก (rice porridge), salapao (steamed buns), kuaitiao rat na (fried rice-noodles) and khao kha mu (stewed pork with rice). With over 40 distinct ethnic groups each with its own culture and even more languages, it comes as no surprise that Thai cuisine, as a whole, features many different ingredients (suan phasom; Thai: ส่วนผสม), and ways of preparing food. With over 40 distinct ethnic groups each with its own culture and even more languages, it comes as no surprise that Thai cuisine, as a whole, features many different ingredients (suan phasom; Thai: ส่วนผสม), and ways of preparing food. Palm sugar, made from the sap of certain Borassus palms, is used to sweeten dishes while lime and tamarind contribute sour notes.
The most notable influence from the West must be the introduction of the chili pepper from the Americas in the 16th or 17th century. It is now one of the most important ingredients in Thai cuisine, together with rice. During the Columbian Exchange, Portuguese and Spanish ships brought new crops from the Americas including tomatoes, corn, papaya, pea eggplants, pineapple, pumpkins, culantro, cashews, and peanuts. Thai farmers historically have cultivated tens of thousands of rice varieties.
A Thai family meal would normally consist of rice with several dishes which should form a harmonious contrast of flavors and textures as well as preparation methods. The fork and spoon were introduced by King Chulalongkorn after his return from a tour of Europe in 1897 CE. Sticky rice, not jasmine rice, is the staple food in the local cuisines of Northern Thailand and of Isan (Northeastern Thailand), both regions of Thailand directly adjacent to Laos with which they share many cultural traits. Once the rice is steamed or cooked, it is called khao suai (lit. Black sticky rice is a type of sticky rice with a deep purple-red color that may appear black. "rice covered with curry"), or for short khao kaeng (lit. Wun sen, called cellophane noodles in English, are extremely thin noodles made from mung bean flour which are sold dried. In his book The Principles of Thai Cookery, celebrity chef, writer and authority on Thai cuisine McDang wrote: "What is Thai food? Every country in the world has its own food profile. Thai food was traditionally eaten with the right hand while seated on mats or carpets on the floor, customs still found in the more traditional households.