Cracking the Nut: How are Pistachios Shelled?

Pistachios are one of the healthiest snacks available in the market, being rich in protein, antioxidants, and healthy fats. They are enjoyed by people around the world and form an integral part of many cuisines. While most of us enjoy eating these delicious nuts, have you ever wondered about the process that goes into shelling them? How are pistachios shelled? Let’s take a closer look.

The Pistachio Tree and Harvesting Process

Pistachios are the seeds of a tree that belongs to the cashew family. The trees primarily originate from regions above the Middle East, such as Iran, where they have been cultivated for thousands of years. The cultivation process for pistachios is quite detailed and requires specific weather and soil conditions.

Once the tree bears fruit, the process of harvesting begins, which is typically carried out by hand or machine. It is recommended that the harvesting be done manually to avoid damaging the tree itself. The ripe fruits are then collected and left to dry for up to four hours.

Removing the Outer Shell of Pistachios

Once the fruits have been harvested and dried, the next step is to remove the outer shell. The outer shell of the pistachio is a hard, cream-colored shell that needs to be cracked open to reveal the nut inside.

Traditionally, the process of cracking the outer shell involved using rocks, hammers or teeth! But today, the machines have replaced the manual process. Pistachios are now usually boiled before being mechanically hulled with a machine.

Machine Shelling:

The pistachio hulling machine works by creating high-speed air currents and impact. These machines work by cracking the pistachios’ shells and separating the shells from the nuts. The machine has a unique design that causes the pistachio shells to crack uniformly, resulting in minimal kernel damage. That means that the beautiful, green interiors are fully intact and not damaged. The kernel processing is completed by sorting, and grading machines.

Other machines for shelling pistachios may exist, such as laser or acoustic technologies, but high cost compared to mechanical shelling systems. Out of these machine shelling systems, mechanical systems have proven to be more efficient.

Hand Cracking:

Although manually cracking pistachios is more labor-intensive and time-consuming compared to machine shelling, some small scale farmers and markets still use the traditional method. It is a tedious process, but the results are uneven but some of the best-tasting pistachios come from this method. In this method, pistachios are cracked open using a handheld machine called a ‘sheller,’ where the shell has to be manually positioned.

Sizing and Grading the Pistachios

Pistachios from machine shelling are then sized and graded by grade sorters which have an electronic colour grading system that rejects low-quality nuts. Mechanical shelling has accelerated the rate of the pistachio nut’s commercialization, especially in Iran, where 90% of the world’s pistachios are produced.

The Final Word

Shelled pistachios make a perfect snack and ingredient in different recipes. The modern-day machines have made the elegant looking nuts more accessible and affordable. The next time you enjoy a handful of these nuts, remember the hard work involved in bringing this healthy snack to your table.

Reference List:

  • Swanson, R. B., & Bradley Jr, G. W. (1989). Effect of equipment design and conditioning temperature on pistachio splitting efficiency. Transactions of the ASAE, 32(5), 1379-1384.
  • Darvishzadeh, M., & Nemati, A. (2008). Evaluation of a new ultrasound machine for pistachio splitting. Journal of Food Engineering, 88(4), 503-509.
  • Tavakoli, H., Rajabipour, A., & Kalbasi-Ashtari, A. (2011). Mass transfer kinetics and the effect of ripening duration on pistachio microstructural changes during hot-air drying. Journal of food processing and preservation, 35(3), 269-277.


  • Q. Are Pistachios hand cracked or machine cracked?

    A. Pistachios can be hand cracked, but they are typically machine cracked. This process is faster and more efficient.
  • Q. Can you shell pistachios with your teeth?

    A. While it’s technically possible to shell pistachios using your teeth, we don’t recommend it. It can lead to tooth damage, and the process is time-consuming.
  • Q. How are pistachios sized and graded?

    A. After the shell has been removed, pistachios are sized and graded using electronic colour grading systems that detect low-quality nuts.
  • Q. Are all pistachios mechanically processed?

    A. No, some small-scale farmers and markets still use the traditional method of hand cracking the pistachios.

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