When pistachios are harvested, they are usually shaken from a tree and hulled within 24 hours. If harvesters wait more than 24 hours before hulling, the pistachio's inner shell -- which is commonly bagged for sale -- might be stained with a rose colour, depreciating its value. In order to avoid losing a harvest, farmers tend to quickly go about hulling their pistachios. Removing the hull of a pistachio is a fairly simple process and can be achieved through a few steps.
Grab the raw pistachio firmly in one hand over a plate to catch the debris that hulling produces. Try not to let the pistachio slip from your fingers as they are quite soft.
Use your free hand to puncture the soft hull with your fingernail. You can also use any other sharp object such as a knife.
Peel the soft skin back with your fingers until the pistachio is completely free of its hull. When the pistachio is free of its hull, you'll be able to see the hard, white inner shell of the nut.