Home | About macadamias

About macadamias

Macadamias grow best in Australia because that’s where Mother Nature intended them to be grown. It was on the north-east coast of Australia that macadamias evolved more than 60 million years ago.

Commercial production of macadamia nuts, the only Australian native plant that has been developed commercially as a food crop, is centred in northern New South Wales and south-east Queensland. These areas provide the rich soils and high annual rainfall needed for the crop to flourish.


It can take up to 15 years for a macadamia tree to reach maturity and maximum yield. Mature trees grow to heights of between 12 and 15 metres and have shiny dark green leaves. Optimum growth occurs between 20 and 25 degrees Celsius.

Macadamias are prolific producers with each tree bearing sprays (racemes) of 40 to 50 flowers which produce from four to 15 ‘nutlets’ that ripen into nuts. Flowering occurs in early spring with nuts forming in early summer and, by early autumn, clusters of plump green nuts appear. The nuts grow encased in a hard, woody shell, which is protected by a fibrous husk. The nuts fall to the ground between March and September each year and are machine harvested at regular intervals during these months.


The fibrous outer husk of the macadamia is removed within 24 hours of harvest to reduce heat respiration and facilitate drying. The husk material is usually recycled as organic mulch, and the ‘nut-in-shell’ (NIS) is generally sent to a commercial processor.


Careful drying to maximise shelf life and quality of the end product is a critical step in macadamia processing. At harvest the nuts have a moisture content of up to 30%. Drying can take up to three weeks and reduces the moisture content to around 1.5%. The kernel shrinks away from the inside of the shell and allows the shells to be cracked without damaging the kernel.


Modern machines crack the tough shell of the macadamia without damaging the precious kernel within. These machines have either a fixed blade and cutting blade, or a combination of rollers and a base plate to compress the shell.


Australian exporters have developed major markets for bulk raw macadamia kernel in many different grades; value added products and retail packs. More than 60% of the nut-in-shell produced in Australia is exported as kernel to the world market. The Australian market has expanded enormously in recent years with many new, high quality, value-added products available.

  • iep 0116

    NIS w kernel small cropped


You are here: Home | About macadamias