Vietnam’s diverse climate makes for some remarkable differences across the country: while June marks the end of the mango season in the South, the dracontomelon fruit are just getting ripe for the picking up North.

Called quả sấu in Vietnamese, the dracontomelon is a symbol of summer in Hanoi. The bright green fruit is associated with Hanoi since they grow on tall trees that line many of the capital’s streets. Its aromatic flesh has a pleasant sourness that is a perfect refreshment on a sultry day.

Whether green or ripe, locals are so accustomed to eating the fruit. Green dracontomelon is a popular ingredient in soups and drinks.

When using it to create basic sour soup, boiled chopped pork is added along with tomatoes, onions and herbs. The unripe dracontomelon, often as large as the tip of a thumb and with a very soft seed, exudes a more distinctive taste and fragrant which it lends to the soup, making unique hearty bowls of sour soup, a delicious dish in Hanoians’ traditional meals.

Among a common favorite by locals is a drink made from the fruit. When its peel is shaved off, it is cut into strips and soaked in sugar water, and some crushed ginger is added to conjure up a slightly sour and sweet taste. This can be added to water and some ice to get a sour, fragrant, sweet taste. This refreshing treat is abundantly sold on sidewalk stalls especially during summer.

Last but not least, sugared or salted dry dracontomelon, called ô mai sấu in Vietnamese, is often bought in bulk by tourists as a Hanoi specialty. How it can be preserved for a long period makes people appreciate this simple fruit even more.