Traditionally, Vietnamese cuisine is based around five fundamental taste "elements" (Vietnamese: ''ngũ vị''): spicy (metal), sour (wood), bitter (fire), salty (water) and sweet (earth). Common ingredients include fish sauce, shrimp paste, soy sauce, rice, fresh herbs, fruits and vegetables. Vietnamese recipes use: lemongrass, ginger, mint, Vietnamese mint, long coriander, Saigon cinnamon, bird's eye chilli, lime and basil leaves. Traditional Vietnamese cooking is known for its fresh ingredients, minimal use of oil and reliance on herbs and vegetables; it is considered one of the healthiest cuisines worldwide. The use of meats such as pork, beef and chicken was relatively limited in the past. Instead freshwater fish, crustaceans (particularly crabs), and molluscs became widely used. Fish sauce, soy sauce, prawn sauce and limes are among the main flavouring ingredients. Vietnam has a strong street food culture, with 40 popular dishes commonly found throughout the country. Many notable Vietnamese dishes such as ''gỏi cuốn'' (salad roll), ''bánh cuốn'' (rice noodle roll), ''bún riêu'' (rice vermicelli soup) and ''phở'' noodles originated in the north and were introduced to central and southern Vietnam by northern migrants. Local foods in the north are often less spicy than southern dishes, as the colder northern climate limits the production and availability of spices. Black pepper is frequently used in place of chillis to produce spicy flavours. Vietnamese drinks in the south also are usually served cold with ice cubes, especially during the annual hot seasons; in contrast, in the north hot drinks are more preferable in a colder climate. Some examples of basic Vietnamese drinks include ''cà phê đá'' (Vietnamese iced coffee), ''cà phê trứng'' (egg coffee), ''chanh muối'' (salted pickled lime juice), ''cơm rượu'' (glutinous rice wine), ''nước mía'' (sugarcane juice) and ''trà sen'' (Vietnamese lotus tea).