Longans are mainly divided into two types: dried longans and fresh longans. Dried longans are actually made from fresh longans that have been sun-dried and processed, so they are the same thing, also known as longans.
The weight of dried longans is lighter than that of fresh longans because most of the moisture has evaporated. The flesh of fresh longans is translucent and tender, while the flesh of dried longans is dark brown. Fresh longan flesh tastes sweet and juicy, whereas dried longans have a taste similar to brown sugar with a soft candy-like texture.
Dried longans can be used in soups, dishes, and for making tea, while fresh longans are usually eaten directly. Fresh longans are more likely to cause "heatiness" (a concept in Traditional Chinese Medicine) than dried longans, which are considered milder.
In the eyes of Cantonese people, dried longans and fresh longans are considered two completely different things. Why? Because dried longans are classified as a type of medicinal herb, believed to replenish qi and blood, calm the mind, and aid sleep. It is a nourishing but not greasy medicinal ingredient. On the other hand, fresh longans are considered a type of fruit. Although they are sweet and delicious, they are prone to causing "heatiness," similar to lychees.