There are about 9 different species of Macadamia trees. Only two of these, “Macadamia Integrifolia” and “Macadamia Tetraphylla”, produce nuts that are edible. The other 7 just produce nuts that are too small and that taste very bitter.
The nut of the “Macadamia Integrifolia” has a smooth shell, and is up to 80% oil. The “Macadamia Tetraphylla” nut has a rough shell and a bit of a lower fat content (65 to 75%.) There are now over 40 different cultivars that have been bred from these two species.
The nuts grow with a very hard shell surrounded by a dark green husk. Inside the marble-sized nut is white. They are usually harvested by waiting for the nuts to fall to the ground, because shaking the tree can bring down nuts that aren’t ripe yet.
When eaten fresh off the tree, the texture of Macadamia Nut is creamy, almost like the inside of a fresh coconut. They must be dried for storage and shipping, however. Even when dried, they still end up with a rich, buttery flavour.
They are grown in Australia, Brazil, Central America, Columbia, Hawaii and South Africa.
One of the highest fat contents of all nuts: 73%.
Macadamia Nuts are native to Australia. They were found by an explorer named Alan Cunningham in 1828. A botanist named Baron Ferdinand von Mueller (1825-1896) catalogued them in 1857 and named them after a Dr John Macadam (1827-1865), who was his friend. Macadam was a Scotsman who promoted the nuts. He had emigrated to Australia in 1855 and become a member of Parliament for Victoria State.
The tree was introduced into Hawaii in 1881 by a William H. Purvis.
Large scale production didn’t start in Australia until the 1960s. The Hawaiians were ahead of them and started in the 1930s.
In the Brisbane botanical gardens there is still growing (as of 2004) a Macadamia tree that was planted in 1858.