Itchy Nuts: Why Cashews Are Always Roasted

Those of you blessed with the knowledge of boiled peanuts know what everyone else is missing. Roasted peanuts in the shells are delicious, too, so there is inherent culinary joy in cracking open a nut, right? But you won’t see cashew nuts in their shells at your local grocery store or ballgame. So, why is that? Why can’t you buy “whole” cashew nuts in their shells? And while we’re at it, why are they always roasted?

Angry Anacardiaceae

The cashew tree is part of the Anacardiaceae classification of flowering plants. Even if you’re not a nut lover, you’re likely familiar with other Anacardiaceae family members. The group includes such delightful greenery as poison ivy, poison oak, sumac, Peruvian pepper, and, more recently, pistachio. It took some time for botanists to agree the pistachio tree was irritating enough to hang with the others.

Here’s the dark family secret. Plants and trees in this family can contain urushiol. This is the oil that causes so much grief among campers, yard workers and outdoor enthusiasts of all kinds. Once urushiol has an opportunity to be absorbed into the skin, it causes that persistent rash we all know and love. Oh, and that oil sticks around for a long, long time, so contact with contaminated clothes, boots, gear, or tools can still get ya long after you leave the ivy patch.

Just to close the loop on this, cashews are part of the Anacardiaceae group. The Anacardiaceae members are usually capable of oozing urushiol from somewhere. Urushiol gives you rashes. Ipso facto e. Pluribus unum, cashews will give you a skin condition.

If you’re one to enjoy cocktail nuts, you’ve probably noticed you haven’t broken out in itchy rashes after hitting the nut bowl. Here’s why…

Cashew Apples

Cashews grow in a kinda bizarre fashion. The nut (complete with shell) is attached to the exterior of a cashew “apple.” It’s kind of like Professor Quirrell in Harry Potter, who had an evil dark lord protruding out the back of his head. The apple is edible when fresh, but the nut presents an interesting harvesting challenge.

That urushiol is inside the shell, between the outer shell and the cashew nut itself, and it’s got to go before handling and ingestion. So, cashew farmers have to exercise care when shelling the nuts, and even then, the nuts themselves are likely contaminated with urushiol after shucking.

Save a Life! Roast Your Nuts, Please…

OK, so I might be slightly dramatic here, but while roasting nuts may not save your life, it will avoid potential unpleasantness.

There’s a reason the cashews you find in stores are always roasted. As we just discussed, raw cashews are likely to be contaminated with urushiol, and that often causes nasty and unpleasant rashes, blisters and itching. Most grocery stores agree it’s generally bad form to sell food causing such adverse effects when handled and eaten.

The good news is the heat of the roasting process destroys those urushiol oils, making cashews safe to handle and eat. Even if you do encounter “raw” cashews for sale, they’ve likely been cooked or similarly treated to destroy those nasty oils. Good thing. Poison ivy of the mouth would be sure to ruin your appetite.

Bon appetit!