Learn What’s True About The Cashew

Learn What’s True About The Cashew

Just like we discovered with almonds, there’s something surprising about cashews that many people don’t know. What we call a cashew “nut” isn’t actually a nut at all. Let’s explore this fascinating truth about one of the world’s favorite snacks.

What Makes Something a True Nut?

As we learned in our almond post, true nuts have specific characteristics:

• They are fruits
• They are dry
• They contain one seed
• They have a hard shell
• They have a protective husk
• The seed isn’t attached to the fruit wall
• They are indehiscent (don’t split open at maturity)

What is a Cashew?

The cashew (Anacardium occidentale L.) produces what we think of as a nut, but it’s actually a seed that develops in a unique way. Unlike true nuts, the cashew seed develops at the end of an enlarged, fleshy peduncle, technically called a pseudofruit or false fruit (the cashew apple) – a characteristic that distinguishes it from most other fruits and nuts we eat.

The Unusual Cashew Structure

When a cashew tree flowers, it develops two distinct parts:

• The cashew apple – an enlarged, fleshy peduncle that becomes pear-shaped and juicy. This pseudofruit deteriorates within 24 hours at room temperature and is primarily used locally in growing regions for juices, preserves, and other products

• The cashew seed – which develops within a complex shell structure that makes up approximately 50% of the raw nut weight. The shell consists of three distinct layers: an outer shell (epicarp), a middle layer (mesocarp) containing phenolic compounds including anacardic acid (the caustic resin), and an inner shell (endocarp)

This unusual arrangement means that the cashew seed hangs beneath its peduncle rather than growing inside it, like most fruits and nuts do. The seed’s protective layers require careful processing at high temperatures to neutralize the caustic compounds before the cashews can be consumed. This processing requirement explains why cashews are always sold shelled and processed.

Growing Conditions

Cashew trees thrive in tropical climates with temperatures between 63-100°F (17-38°C). They require well-drained soils and can tolerate drought conditions once established. These trees typically begin producing seeds after three to five years and maintain optimal production for 20-30 years, though they can live and produce for several decades beyond this period.

How Does This Compare to True Nuts?

Unlike hazelnuts or acorns, which are true nuts that develop their seeds inside a hard shell within the fruit, cashews develop differently. Think about how an acorn grows inside its cup, or how a hazelnut develops within its husk. The cashew does the opposite – it grows outside its pseudofruit in a unique protective structure.

Why Do We Call Them Nuts?

Like almonds, we call cashews “nuts” because that’s how we use them in cooking and eating. They have a similar nutritional profile to true nuts, and we consume them in similar ways. This is similar to how we might call a tomato a vegetable in cooking, even though botanically it’s a fruit.

If you found learning about cashews interesting, check out our other posts on our TrueTreeTalk blog. Follow us on Facebook to keep up with these and other posts. Check out our list of blog posts grouped by topic for more to read.

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