Where cashews come from: a plain explainer

Cashews are one of the odd ones. Pick one up and it looks like a plain, curved, creamy snack. But they grow in an unusual way, need more processing than most nuts, and belong to a family that includes some surprising relatives. Here is how a cashew gets from tree to jar, in plain terms.

The tree and the apple

The cashew tree is a tropical evergreen. It thrives in warm, frost-free climates, and it is grown in many parts of the world's tropical belt. You can read a general overview on the cashew page on Wikipedia.

The odd part is the fruit. What looks like the fruit, a fleshy, pear-shaped, yellow or red body, is called the cashew apple. It is a swollen stalk, not a true fruit. The real fruit is the grey-green, kidney-shaped shell that hangs off the bottom of it. Inside that shell sits a single seed: the cashew we eat.

The cashew apple is edible, juicy and rather astringent, and is used locally for drinks and preserves. It bruises easily and does not travel well, so you rarely see it outside growing regions.

Why you never see them in the shell

If you have shopped for almonds or pecans, you may have noticed that you can buy them in the shell. Cashews are almost never sold that way, and there is a good reason.

Between the outer shell and the seed is a layer containing a caustic oil. It can irritate skin, and it is related to the irritants found in some well-known plants. Because of this, cashews cannot simply be cracked open like a walnut. They need careful handling and a processing step to deal with the shell safely.

So the cashew you buy has already been shelled, dealt with and peeled. This extra work is part of why cashews often cost more than some other nuts.

From tree to bag

The path varies from place to place, but the general steps look like this:

1. Harvesting. Nuts are collected once they have fallen or been picked from the tree. The apple is separated from the shell.
2. Drying. The shells are dried in the sun so that they are easier to handle and store.
3. Treating the shell. Heat, such as steaming or roasting, softens the shell and deals with the oil inside it.
4. Shelling. The shell is cracked open, by hand or by machine, to release the kernel. It is fiddly work, because the kernel is delicate and breaks easily.
5. Peeling. A thin skin around the kernel is removed after drying.
6. Grading. Kernels are sorted by size and whether they are whole or broken. Whole pieces are usually more expensive. Broken pieces are perfectly good for sauces, cooking and butters.

Because of the shape and fragility of the kernel, a lot of this still relies on human hands, even where machines help.

Raw cashews are not quite raw

A small surprise: cashews sold as raw have normally been heated during shell processing. That gentle step is part of making them safe to eat. When we say raw cashews, we mean they have not been roasted or flavoured afterward. If you want to understand what roasting adds, see our post on raw vs roasted nuts.

Cashews in the kitchen

Cashews are soft, mildly sweet and rich, which makes them very flexible.

• Eat them as they come, or choose salted roasted cashews for an easy snack.
• Go for flavour with chilli lime cashews if you like heat and zing.
• Blend them into a smooth, creamy cashew butter, or make your own with our food processor nut butter guide.
• Soak and blend raw cashews to make a creamy base for sauces and dairy-free desserts.
• Toss into stir-fries and curries for crunch and richness.

Are they nuts?

Botanically, the cashew is a seed that grows on the outside of its fruit, so the botanical definition does not match what we mean in the kitchen. In cooking and on the label, though, it is treated as a tree nut. That matters for allergies, covered in our guide to reading food labels.

Storage

Cashews are rich in oil, so keep them in an airtight container away from heat. If they smell sharp or paint-like, they have gone off.

In short

A cashew is a seed hanging beneath a swollen fruit stalk, protected by a shell you do not want to bite. It needs treatment, shelling and peeling before it reaches your bowl. Seen that way, the price makes more sense.

For allergy questions, read the label and speak to a qualified professional.