It is often said that in China, very little of an animal is left to go to waste. The Chinese have concocted a clever variety of methods to ensure that every last morsel of nutrition is extracted from any animal killed for food. Blood is no exception. And it's not just the Chinese that enjoy sucking it down.

Blood is used all over the world, from adding flavor to sausages to simply being fried up with onion in Hungary. In France, chicken's blood is sometimes used to thicken coq au vin, and in Britain there is a famous dish called black pudding, which is made from congealed pig's blood; it's my all-time favorite component in a full English breakfast.

Walking through a street market in China, it's apparent that almost anything can be turned into a mouth-watering snack simply by skewering it onto a stick. Though it seems improbable, if not impossible, blood is often served on a small wooden skewer as well. This blood has been left to congeal, giving it a more jelly or tofu-like consistency.

Known as blood tofu (xuedoufu), congealed blood on sticks isn't hard to find. Most commonly, duck and pig's blood is used to make such tofu, but there are few restrictions on what other animal platelets might be used in this fashion, and preferences vary regionally.

When an animal is slaughtered, normally by slitting the throat, the blood is collected below the dripping corpse. While the meat is taken away to be used elsewhere, the blood is carefully laid out in large trays of about one inch deep, where it congeals and solidifies to a jelly-like state.

Blood tofu on a stick is normally dipped in boiling hot and spicy soup (malatang) to warm it up and cook it slightly before consumption. The flavor is not deceitful – blood tastes like blood, as though you've bitten your lip. It's not horrible, but hard to imagine eating an entire skewer's worth, no? But actually, the flavor in these skewered blood cubes primarily comes from the spicy, tongue-numbing soup, with just a metallic tinge from the iron in the blood itself. It's hardly anything to write home about, except that telling friends back home you've been eating blood can have a fun, cringe-worthy effect.

Why have it then? Historically, people have eaten blood when there was a lack of food and nothing, if possible, went to waste. Blood is also said to provide its consumers with lots of protein and some minerals, such as iron and vitamin D. Duck's blood in particular is also said to be very good at reducing yang and/or increasing yin, cooling the body.

These blood cubes are not only served on sticks, they also often crop up in various dishes served in restaurants to add subtle flavor, color, texture or nutrition to dishes. It's a common ingredient in hot pot, and if breakfasting in south China, it's not unusual to receive a serving of congee with a couple of hunks of congealed blood to enhance your otherwise bland rice soup.