Cassia and Cinnamon are closely related trees native to Asia. While they are often used interchangeably, their flavors are somewhat different. As a result, I’ll start by writing a bit about cassia and then move on to true cinnamon.
Cassia, Cinnamomum aromaticum, is more commonly known as Saigon, Vietnamese or Chinese cinnamon. It is harvested from the bark of whole branches or small trees. It has a harsher, stronger flavor than true cinnamon and is considerably less expensive. It is used extensively in the U.S., whereas true cinnamon is preferred in Mexico, South America and Europe.
Cassia was primarily produced in Vietnam until war shut down most production in the 1960s. The island of Sumatra in Indonesia is now the largest producer of cassia, though Saigon cinnamon has recently become available in the U.S. again. The Korintje or Indonesian cinnamon has a lower oil content than the Vietnamese variety and is the least expensive. The Saigon variety is a better quality cassia.
Both cassia and true cinnamon are used to lower blood glucose levels, as well as to lower cholesterol and triglicerides. It appears that both work well, though some research indicates that true cinnamon is the better choice. In fact, cassia contains coumarin, a blood thinner that can have deleterious effects on the liver and kidneys when consumed in large amounts. For this reason alone, it is wiser to use true cinnamon as a supplement for blood sugar and cholesterol control.
True Cinnamon, Cinnamomum verum and C. zeylanicum, and often known as Ceylon cinnamon or canela, comes from a tree native to Sri Lanka, which was originally known as Ceylon. The flavor of both cassia and cinnamon come from oils in the bark, which are peeled in quills from the trees. Ceylon cinnamon, which comes from the thin inner bark of tree shoots, has a finer, less dense, and more crumbly texture. It is also milder in flavor, not as harsh, and has delicate citrus notes. It is more prized and expensive than cassia. There are negligible amounts of coumarin in Ceylon cinnamon.
Ceylon cinnamon has a long and illustrious history. It was mentioned in the Old Testament, and was traded in Egypt as early as 2000 B.C. Arab traders brought it overland to Egypt where Venetian traders bought it and early-on held the monopoly in Europe. In Indonesia, it was taken by raft from the Moluccas to East Africa. It was then traded north to the Roman Empire. Portuguese explorers found it in Ceylon and controlled the trade until the Dutch took charge of the Island in the 1630s. The British wrested Ceylon from the Dutch at the end of the 1700s, but by then, cassia had made inroads into the cinnamon trade, and there was a greater world demand for chocolate, vanilla, coffee and tea.
It is easy to distinguish the quills of cassia from Ceylon cinnamon. Ceylon cinnamon has many thin layers in its quills. They are easy to crumble and to grind in a coffee or spice grinder. Indonesian Korintje cinnamon (cassia) on the other hand, usually has only one layer per roll and is hard enough to damage a spice grinder. Chinese and Saigon cinnamon (also cassia) is sold in broken pieces as it is too hard to remove as quills. Once the cinnamon is ground, it can be much more challenging to tell one from the other, though by taste cassia is both stronger and harsher.
Cinnamon is used nearly worldwide in cuisine as a flavoring in savory dishes, sauces, desserts and beverages. In some countries it is drunk as a tea to warm the body and to fight off colds. It is a key ingredient in traditional Chinese medicine. It is very high in antioxidants and has anti-microbial qualities, which makes it useful for treating respiratory and gastro-intestinal illnesses, and it is used in food preservation. It is also powerful in controlling blood sugar and cholesterol.