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What Is Cashew Nut Processing?

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  • Written By: Dan Cavallari
  • Edited By: Bronwyn Harris
  • Last Modified Date: 05 September 2014
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Cashew nut processing prepares the cashew nut for consumption. In its most basic form, cashew nut processing involves the removal of the cashew shell from the meaty nut, washing the nut to rid it of any foreign matter, then soaking and roasting it. Once this process is completed, the cashew nuts are ready to be eaten.

Traditionally, cashew nut processing was completed manually in small batches. Cashew nut shells would be carefully cracked with hammers to avoid breaking the nut inside as whole nuts hold a higher market value than broken nuts. The nuts would be cleaned with water before being left to soak in tubs. After draining, the nuts would be left to stand for several hours. To manually roast the cashew nuts, vendors would place the nuts in large pans and heat the nuts over an open flame while constantly shaking the pan or stirring the nuts to help prevent them from getting overcooked.

Cashew nut processing can also be completed mechanically at a cashew nut factory. Usually it begins with roasting, which makes extraction easier; manufacturers can extract valuable cashew nut oil in the process as well. Larger-scale operations won’t use an open-pan method but would roast the cashews either in a large, rotating drum or submerge them in tanks filled with hot oil.

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There are at least two different types of mechanical shellers used for cashew nut processing. One type uses blades to separate the shells from the meat while another uses rotary paddles to shove the nuts up against the sides of a barrel. The cashew shells crack with the force of hitting the barrel, but the force isn’t strong enough to break the nut. Should any nuts crack during the shelling process, the whole kernels can be mechanically separated from the broken kernels in a pre-grading stage. To help peel the papery skin from the cashew, cashew nut processors may dry the cashews in large batches using a commercial drier. The drying process usually takes around six hours and makes it easier to remove the skin from the nut.

At this point in the process, the cashew nuts are ready for grading and packaging. Whole nuts that are perfectly roasted are considered Grade 1 while broken pieces of cashews that might have imperfections from the roasting process are considered Grade 2 or 3. The cashew nuts are separated according to the grade and vacuum sealed in containers pumped full with carbon dioxide to keep them fresh. The cashew nuts are ready for their voyage to markets around the world.

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cloudel
Post 7

I was surprised to learn what all cashew nut shell oil can be used for. I used to think that the shells were just tossed away because of how irritating they can be to the skin, but I recently heard that the oil can be used for many different things.

I read that there is a honeycomb inside the shell where a brownish-red liquid is found. This oil is used in paint, rubber cement, a variety of chemicals, and varnishes.

I understand why it could be irritating to the skin. Most of the products it is used to make are also dangerous and shouldn’t come in contact with your skin.

kylee07drg
Post 6

@OeKc05 - I’ve tried cashew apple juice, and it does slightly resemble the taste of the cashew nut. It’s strange to think of fruit juice tasting nutty, but this is a special kind of fruit, so it reserves the right to be a little different.

The juice makes my mouth feel a bit puckered and dry the same way that wine or strong tea does. I’m told that this is due to the tannins in it.

I like the strong flavor and slight nuttiness of this juice. It’s not for everyone, because many people do complain about the drying effect it has.

OeKc05
Post 5

@turkay1 - I have heard that the fruit of the cashew nut plant is consumed, as well. I watched a documentary that showed the harvesters popping these in their mouths, chewing them, and spitting out the chewy part.

It’s called a cashew apple, but not many people eat it whole like that, since it goes bad within a day or so after being harvested. Instead, people use it to make jam and wine. So, it’s used to make products that contain preservatives.

I wonder if the apple tastes like the cashew or if it has its own distinct flavor? Has anyone here ever tried cashew apple wine, jam, or the fruit itself?

wavy58
Post 4

I never knew that whole cashews were considered better than half cashews. I usually buy a can of roasted, salted mixed nuts, and it has several cashews that are perfectly broken in half in it, along with a few whole cashews.

I suppose that maybe this is where the broken cashews go to be sold for a profit, since they are deemed unfit to be packaged with the whole ones. I don’t mind eating cashew halves at all, because they taste the same, no matter how they are divided.

A lot of recipes that I use call for chopped cashews, so I will be breaking them up, anyway. I never buy whole cashews for this, since the broken ones are so cheap.

burcinc
Post 3

Really great information here! I learned a lot from the comments too!

It's always amazing to me that machinery can be used to remove the shells of nuts. It must be a very sensitive system. I often buy nuts with shells on and crack them at home and I can rarely do it without breaking the nut.

Still, cashew production doesn't appear to be as automated as some other nuts. I saw a program about African nut production on TV. They showed a cashew factory and even though the factory had machinery, the machinery was still operated by workers. A worker actually had to place the cashews by hand on the machine and push two blades together that would break them open.

I guess it's better than doing it all by hand, but it still is a lot of work. I wonder if there will ever be machinery that can do the entire process completely on its own and correctly? What do you guys think?

burcidi
Post 2

@turkay1-- Yes, the shell is always removed and only the nuts are sent for processing. The fruits are sold fresh locally.

The reason why the shells are removed is not because it's hard for customers to break them. It's removed because it's covered with irritants. This is also the reason why cashew nuts have to be roasted, because roasting them gets rid of harmful irritants.

Cashew comes from the same family as poison ivy. Someone who handles raw cashews will develop an allergic reaction on their hands regardless of whether the shell is on or not. In order for cashews to be safe for consumption, the shell has to be removed and the nut has to be roasted.

Workers who remove cashew shells manually have to wear protective gloves while working. Another reason why most of the work at a cashew factory is done by a cashew nut processing machine is because of the irritation raw cashews cause.

candyquilt
Post 1

Has anyone seen a picture of a cashew nut tree? I saw a picture of it at school and it's the most amazing thing! The nut is attached to the cashew fruit and there is only one nut per fruit. The fruit looks like something between a pear and a red or yellow pepper and the nut is hanging on the bottom portion.

I guess for processing, the nut is separated from the fruit before it is sent to the factory right?

And are cashew nuts ever processed with the shell on? I've never seen cashew nuts at the store that have the shell. I guess the shell is too hard for us to break. Is that why they always remove it during processing?

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