How are nuts de-shelled?

I refer to packaged nuts of course. Are they removed: by machine? By hand? I assume that the de-shelling of say peanuts which can be done fairly quickly would be best done by hand. I can’t imagine how a machine could be constructed to de-shell nuts without destroying the kernel.

Walnuts in particular; I have often wondered how it is possible to extract the kernel of a walnut in two intact pieces.

Hazelnuts would be easy though, I would think; you could just run them between a pair of heavy rollers that were set apart just enough so that the shell cracked, but the kernel didn’t.

Is any mass market product produced by hand, these days? I’m betting the whole process is mechanized, although I have no idea how one would construct the necessary machines, either. Most likely, any damaged nut meats are either packaged as chopped nuts or used for other products, like peanut butter.

Kind of as an aside, it definitely is possible to remove walnut halves intact by hand. It takes a bit of practice and concentration on what you’re doing, but I can do it about 70% of the time, using a standard hinged, handheld nutcracker.

I suspect there is also a minimum threshold of hand strength required, because I’ve never known a woman who could do it. (I don’t know any women farmers or construction workers.) I suspect the reason is that it’s crucial to stop applying pressure at the right time. If you’re putting all your strength into just getting the darn thing to crack, it’s harder to stop in time.

I believe that it’s particularly difficult to completely automate the processing of cashews. From this page,

However, science marches on, and I believe that cashew nut processors are continuing to work on further automating cashew production. A more complete and technical description of current techniques in cashew nut processing can be found here (warning, PDF file):

In some nations where peanut farming is done on a small-scale or community level, a simple de-sheller is made by building a narrow wooden box around a car wheel (tire on). Peanuts are dumped in the top front of the box while the tire is hand or machine cranked. The distance between the tread of the tire and the edge of the box is less than the width of the average shell but greater than the width of the average peanut. When the peanuts become lodged between the box and the spinning tire, the shell breaks, dislodging the peanut. The broken shell and nut fall to the lower half of the box where air produced by the spinning tire blows away bits of shell and skin while the streamlined nut pieces drop into a box.


We use the shell parts (mainly pecan) as “lost circulation material” in the oilfield all the time.


Recycled nut shells are used for all kinds of things; where do you think walnut furniture comes from?

Let me guess, Fear Itself, you do most of your furniture shopping at Walmart?

Ummm…there is such a thing as a walnut tree!

Oompa-loompas do it of course!

A friend of mine in Delhi was taken by an ex-pat to see a small boy in the Old Market. This child, 9 years old, squatted between three baskets. The first was full of whole walnuts, the other two had walnut shells and walnut meat in them respectively. He had a flat rock and a rounded rock, and all day long he cracked walnuts, and separated them by hand. He got to the market at 5am and left at 9pm. His salary was (US) 80c per day.

Sure, the wages are low for the 9 year olds in the asian sweatshops, but what the heck, they make up for it with the extra hours…