29 August 2021

Covert Cashew: The Secret Life of a Nut

It’s difficult to know quite where to start when it comes to the cashew nut.  To many people it is nothing more than an occasional (if moreish) snack. So, let’s begin with a picture of one on the tree – there it is, above.  Not quite what you expected?  It’s a nut with a number of secrets hidden in plain view, not least the way it grows. And before we go any further, let’s get another thing straight: it isn’t a nut either.

The way it grows will only be a surprise to you, of course, if you live outside the regions where it is farmed – and there is one good reason for that too.  Originating in Brazil the cashew was introduced elsewhere in the 1500s and is now grown in countries such as India, Nigeria, Ivory Coast and Vietnam. In fact anywhere between the latitudes of 25°N and 25°S, where the tropical evergreen can flourish, it is farmed.  It takes shape like this...

Image Credit Michael Khor
Image Credit David Amsler
Image Credit David Amsler
In the home, the restaurant kitchen or the club, what we prepare and eat is known as a cashew nut but we are, in fact, referring to the seed.  The botanic trumps the culinary every time.  So that means that the bulbous growth above must be the fruit of the seed, then? Not quite…

Image Credit barloventomagico
There’s a little more to it than that.  The yellow pear-shaped structure you can see is called the cashew apple.  Scientifically, this kind of growth is known as an accessory fruit (sometimes even a false fruit).  This is an enlarged fleshy structure that forms below (or above, depending on your perspective) the fruit, from the pedicel.  This in turn is the stem that connects each flower in a cluster (aka an inflorescence which is a beautiful word if ever there was one).  So where is the real fruit hiding?

Image Credit Jaoa Vicente
Like so much about the cashew, it is in plain sight.  The ‘nut’ you can see attached to the ‘apple’, above is in fact a drupe.  It is shaped very much like the nut – think of a boxing glove or a kidney - and that’s because the nut is inside it.  So the true fruit of the cashew tree consists of skin (exocarp), flesh (mesocarp), a shell (endocarp) and the seed – our beloved cashew nut. Confused? Think of the last peach you ate and run through the four components again – that’s what makes up a drupe.

Image Credit soma samui
As a result of the widespread perception that the seeds are on the outside, as it were, the Tamil speakers of India have a dual-meaning for their word for cashew.  As well as describing the cashew, the word mundhiri is also used to describe someone who is something of a nosey parker – the fruit does look like a nose sticking out, when you look at it that way.

Image Credit Richard Vignola
Cashews can be harvested in a number of ways, all of which are labor-intensive.  These Vietnamese workers have opted for the ‘long stick and prod’ method.  The apple only engorges about two weeks before the fruit is ready to pick and is an indicator that harvest time is near. Left to their own devices, the apple and fruit fall to the ground of their own accord.

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Image Credit abcdz2000
After they have been picked, it is time for shelling and smoking.  To those working in this industry it must seem like one of the seven labors.

Image Credit David Stanley Smoking cashews in Guyana
Image Credit SidTheSquid Smoking cashews directly off the tree, Guyana
After removal from the tree the cashew ‘nuts’ are taken from the drupe and smoked.  This must be done outside as – believe it or not – they contain a potentially deadly poison.  The shells contain anacardic acid which is similar to the toxin found in poison ivy.  If the cashews are smoked indoors then the chance of breathing in the poison, which is carried in the smoke even as it is removed from the cashew, is greatly lessened.  This is why you will never get to shell a cashew nut while you sit at the bar sipping your gin and tonic and why it will always, always have been roasted. Yet even then you may drop dead if you happen to have an allergy of which you were previously blissfully unaware.

Image Credit FMira
Selling the final product is probably a much easier option than preparing it. This road-side vendor in Mozambique has it down to a fine art.

Image Credit Jim McDougall
After roasting the nuts still have to be sorted - no machinery involved - as seen above in the village of Nitte  in the Indian state of Karnataka.

Image Credit Jim McDougall
Image Credit Jim McDougall
Some cashew factories have adapted technology using what can only be described as a speed-vice to shell the nuts.  The female workers can work so quickly that they can shell fifty cashews a minute for hours at a time.There are over 2 million people working in the cashew industry in India many on illegally low wages.

Image Credit Richard Vignola
This variety on a theme from Vietnam shows just how sharp the edges of the machine must be to cut through the tough exocarp of the fruit.

Image Credit pscadden
So much for the nut – what about the apple? Is it edible? The answer is yes and it is considered by many to be delicious.  If you want to make kids happy from Pakistan to Indonesia, give them a few cashew apples, especially if they have been dipped in boiling water to lessen their slightly astringent taste. In Brazil and Central America it is called the marañón and it, rather than the nut, is considered the true delicacy of the cashew tree (conversely in India it is often fed to the goats). So why, then, do we not see the cashew apple on the shelves of our local food store?  The simple answer is that its skin is so easily bruised that it cannot be transported too far away from where it is grown.

Iamge Credit WallyG
This is something of a shame because as well as its taste the cashew apple contains at least five times more vitamin C than your average orange.  It may not reach far outside of its growth-zone but it never goes to waste.  Often it is eaten fresh but it is also included in local recipes including curries, jams and chutneys.

Image Credit Jason Lawton
Rather more splendidly, the cashew apple can also be fermented - the above home-based brewery in Burma is testament to its popularity.  If you have ever tasted the national cocktail of Brazil (of course it has one), the Caipirinha, then you are likely to have experienced flavor of the cashew apple.  The cashew apple is fermented in Goa where it is used to produce two strong drinks, feni or fenny (40% alcohol) or the slightly weaker urrac which is around 15% alcohol.  In Tanzania the fermented cashew apple comes under the marvellous name of gongo while in Mozambique local farmers have come up with the rather more descriptive agua ardente (burning water) to label their own brand of cashew apple derived liquor.

Image Credit abcdz2000
A traditional fenny distillery in Goa, India. The cashew juice is pourded in to a closed boiler (a big pot, effectively) known as a bhann. A conduit connects the bhann to the launni, a smaller pot which is collects the alcohol.

Image Credit abcdz2000
Nothing is wasted.  After the apples have been crushed a first time they are then gathered together in the shape of a huge cake.  Then a large stone is placed atop the pile to squeeze out the last juice, the last of which that comes out in clear form is known in Goa as Neero.

Image Credit Owen Lin
It seems that whenever humanity encountered a new edible plant species the first question asked was invariably can it be used to make hooch?  Yet once that (obviously very important) question was answered, other avenues were explored and this is true of the cashew tree, nut and indeed apple.

ImageCredit Pandiyan
In Guyana the nuts are ground up to make a poultice to treat snakebites.  When nuts are broken during the smoking process they are not discarded either – they are pressed and the resulting oil is used a salad dressing. The same oil is also used as a natural cure for athlete’s foot as well as other fungal infections. The shell is used for a number of things including waterproofing, adhesives and inks. Even the leaves can be used in salads.

Image Credit maurogaurandi
Image Credit Gary J Wood
Image Credit Dinesh Valke
Of course, there are some poor unfortunates who are allergic to cashews, triggered by their protein content which is not changed by the smoking process rather than the anarcardic acid (which can trigger a nasty skin reaction itself but is active against tooth abcesses, acne, tuberculosis, and MRSA).  So for many the cashew is a treat yet for some it can be life threatening, for others it can get rid of a nasty rash while more still use it to get the party started.

Image Credit Cordelia Persen
The cashew, both ‘nut’ and apple is a fascinating, versatile plant species.  No wonder it was spread by our hand from its original Brazilian home to lands whole continents away.  Yet, it is still unfortunate (a little nuts, you might say) that so many of us will never experience the soft, fleshy joy of a cashew apple.

Image Credit abcdz2000
First Image Credit Hudson