Harvesting Pistachios

Wednesday, August 29th, 2018
harvesting pistachio plants in New Mexico

Pistachios ripen in the month of September almost exclusively around the world except for Australia which harvests in February. In exceptionally hot summers, harvest may be early (last week of August).

The hull of the pistachio is called the epicarp. It is about 1/16 of an inch thick and adheres tightly to the hard-inner shell until the nut is ripe. Take your thumb and forefinger and squeeze the nut. If the epicarp has separated from the hard-inner shell, the epicarp will easily come apart and can be peeled off. Besides the epicarp coming off easily, the color also changes. The epicarp has a reddish/yellow color during development. The color lightens in August and when ripe, it is a rosy, light yellow. Harvest should be timed when most of the nuts are ripe.

How to Harvest Pistachios

Pistachios will fall off the tree when the branches are given a sharp shake. A rubber mallet hitting a branch, a fist or mechanical shaker can be used. Put sheets or tarps under the tree to catch the nuts. You don’t want the nuts to fall in the dirt (you will lose them or the epicarp will tear).

For larger crops, using a mechanical shaker makes the most sense. Pistachio harvesting involves two machines, a shaker and a catcher. Each machine requires an operator to drive and steer the vehicle and control the harvesting operations. The catcher and shaker are self-propelled vehicles with a moveable, tarped, deck that each operator positions under a tree. The decks are angled downward toward the base of the tree, so anything shaken loose from the tree falls down the decks to a conveyor at the bottom of the catcher. The conveyor is driven by a hydraulic motor, and the crop is subsequently separated from debris via an integral blower and ultimately conveyed to bins or a trailer.

Processing Pistachios

The epicarp should be removed within 24 hours after the nut comes off the tree. If left on longer it will start to stain the hard, inner shell and begin to deteriorate. The hull traps moisture which stains the shell if left for a long period of time.

The hull can be peeled off by hand or can be removed by abrasive action. Small growers commonly use an old commercial potato peeler that can rub the epicarp off. Some growers put the nuts in a sack and roll it around with their feet, then dump the nuts and loose epicarp out on a table and sort the nuts from the hulls.

For larger growers, hulls are removed mechanically and then the nuts are washed and dried and separated by size. Drying the nuts down to a stable moisture level without over-drying is the difference between a good pistachio and a great pistachio. The drying process cannot be rushed, nor can it be delayed. Typically, it takes 3-4 days for the nuts to dry on their own, if put on drying tables in the sun.

Those nuts that are not opened naturally on the tree are separated out and electronic sorting machines then check and separate the nuts for any shell staining or discoloration.

From there, pistachios may be salted and seasoned to the desired taste.

Storing Pistachios

Once the pistachios are dry (crunchy to taste), they will keep very well if just a few precautions are taken. In general, the lower the temperature, the longer the storage life of the nuts. Pistachios can be held at temperatures up to 68° F without significant quality deterioration for as long as one year. Prolonged heat turns the oil in any nut rancid. A cool cabinet, the refrigerator or freezer are all good storage locations.

Where to Order Pistachios

To order farm fresh New Mexico Pistachios, shop on-line at www.heartofthedesert.com. The new crop is generally ready to purchase and on shelves in October.

About Heart of the Desert:

Heart of the Desert is a working pistachio ranch and vineyard with four retail establishments in New Mexico. They are best known for their farm fresh pistachios and Award-Winning New Mexico wines. Each store offers wine and pistachio tastings. They offer worldwide shipping and produce attractive gourmet baskets that make great corporate and family gifts. The main store, on the ranch in Alamogordo, offers farm tours that showcases how pistachios are grown and processed as well as a stunning Tuscany themed patio that overlooks the groves and is available for weddings, private parties or enjoying a relaxing glass of wine.