Zongzi. [Photo/IC]

Zongzi are to the Dragon Boat Festival what eggs are to Easter or roses to Valentine's Day.

The first bamboo-wrapped sticky rice dumplings were probably made with plain rice, but these dumplings soon developed into regional specialties. The main ingredient is glutinous rice, which holds its shape after cooking and keeps well in the summer heat. Millet, whole wheat grains, barley, red beans, mung beans or peanuts are also mixed into the rice to make it tastier.

In South China, glutinous rice is also soaked in an alkaline solution that turns the grains yellow, and the process creates a chewy texture. These are jianshui zongzi, which are always eaten dipped into old-fashioned granulated sugar.

Apart from that, the folks in the southern coastal provinces prefer their rice dumplings savory rather than sweet, and the salted dumplings are filled with beans, pork and mushrooms.

Sometimes the rice is fried and seasoned with soy sauce to add fragrance and color. In Guangdong province, the dumplings get bigger and are shaped almost like miniature pillows, filled with five-spice coated fatty pork and plenty of mung beans cooked inside the rice. Often, traditional cooks also add a whole salted egg yolk.

In Beijing and other northern provinces, the preference is for sweet dumplings, filled with sugary red-bean paste. One of the most popular versions is a red bean and rice dumpling, with or without its ball of bean paste filling.

Other ingredients may include fragrant osmanthus flowers, lotus seed paste, walnuts, jujubes, melon seeds or sesame.

It is not just the flavors that vary from region to region. The dumplings come in different shapes as well.

The simplest dumplings are triangular, made with a single large bamboo leaf and simply folded over.

A more traditional shape is the perfect pyramid, with four corners. This is the dumpling that takes the most skill to make. Even if you get the shape right, the challenge is in how to tie it properly so it does not disintegrate in the boiling pot during the long cooking period.