Place the nut inside a strengthened airtight container. Create a partial vacuum by pulling a lever attached to plunger in a long cylinder. Quickly open a valve between the nut chamber and the vacuum chamber: the sudden change in external pressure will cause the shell to break-up outwards leaving a perfect undamaged nut inside. Possibly.
-- Gordon Comstock, Mar 06 2012

Crack-a-lackin http://www.youtube....watch?v=Zz95_VvTxZM
[2 fries shy of a happy meal, Mar 06 2012]

For destructive testing purposes (they can also be used to crack nuts) http://entertainmen...t+put+balls)~meerut
My own pair are quite similar. T.G.F.J. is very fond of them. [Alterother, Mar 07 2012]

Alternative title: "Nuts in Spaaaaaace!"
-- hippo, Mar 06 2012


Yahbut... you only get 14psi pressure so possibly not... peanuts maybe.
-- FlyingToaster, Mar 06 2012


[FT] You are probably correct - certainly wouldn't work for brazils. I was hoping the shock of the pressure change would be enough force a crack or other weakness in the shell. I have absolutely no evidence for this but I imagine (hope even) the structure of nutshells is better at resisting external rather than internal pressure.
-- Gordon Comstock, Mar 06 2012


A 2-stage process might get around the 14psi limit. FIrst place your nuts into the airtight container (obvious straightline here) and gradually increase the pressure to, say, 100 psi then let your nuts acclimate for a few hours. Once the pressure inside the nuts has equalized you are then free to open your container to the vacuum chamber (WARNING - May contain traces of nuts)
-- AusCan531, Mar 06 2012


BTW, Gordon, spheres are the champion shape at resisting internal pressures rather than external.
-- AusCan531, Mar 06 2012


[Auscan531] I like your two stage process - I'd probably not even bother with the vacuum bit - the wait would be hopelessly impractical of course, but that's not usually seen as a problem here.

Re the strength of spheres: yes of course you are right, but nuts usually have a join (although I can immediately think of an exception: hazelnuts) which would tighten under external but weaken under internal pressure.
-- Gordon Comstock, Mar 06 2012


This is fascinating and I would love to have one in my living room. I wonder how quickly the pre-pressurising stage takes? How permeable are nut shells? Would 2 minutes at 100psi be enough?

I would be happy to have foot pedals for the pressurisation and vacuum pump, if hand cranking is not powerful enough.
-- pocmloc, Mar 06 2012


//How permeable are nut shells?//

You are of course controlling the permeability of your nuts by coating them with a clear polyurethane varnish before subjecting them to the vacuum treatment?
-- hippo, Mar 06 2012


I likes it.
I think this bit here;
//the sudden change in external pressure will cause the shell to break-up outwards leaving a perfect undamaged nut inside. Possibly. //
might be mistaken though. Would the shell not implode rather than explode?
[link]

You might think it's too fine a hairline to split, but that's just nuts.
-- 2 fries shy of a happy meal, Mar 06 2012


I feel the urge to grab a scuba tank and some plumbing. [+]
-- AbsintheWithoutLeave, Mar 06 2012


[2 Fries] No, hopefully the shell would explode as there would be a sudden drop in external air pressure.
-- Gordon Comstock, Mar 06 2012


I forsee a marketing problem. In short, don't try and sell these by using direct email promotions.

I picture some seriously disappointed anatomy maximization afficianados when they realize what it's not for.
-- RayfordSteele, Mar 06 2012


You would need the pressurization step, Shirley. But the vacuum could be left off the end, as has been said, by just bumping the pressure up another 14 PSI.

The length of the pressure soak would vary with the species of your nuts. English walnuts are leaky around the joint, pecans have a very smooth and dense shell.

Brazils don't have enough airspace inside to accumulate pressure anywhere but in the meat.

I suggest looking into steam as the pressurizer. I think you will find several food processes that use steam to explode the skins off--potatoes come to mind.
-- baconbrain, Mar 06 2012


Ah, I have it backwards from reading it wrong. I pictured the inner nut pressure equalizing in a vacuum chamber and then suddenly letting external air pressure in.

(+) anyway.
-- 2 fries shy of a happy meal, Mar 06 2012


When I was a kid, my Mother roasted chestnuts in the oven without first poking holes in them. They detonated like little hand grenades, splattering nut-guts all over the place. So I don't know if that is analogous to rapid-nut-decompression, but if it is, then the idea won't work.
-- AntiQuark, Mar 06 2012


The "chestnut" is not actually a true "nut". It's classified as an amphibian.
-- MaxwellBuchanan, Mar 06 2012


ditto the clagnut.
-- DrBob, Mar 06 2012


I really wish you hadn't told me that.
-- MaxwellBuchanan, Mar 06 2012


What about the wingnut?

Is there a way to pre-stress the surface, like Prince Rupert's nuts, so that they are more likely to shatter in certain pre-arranged ways?
-- pocmloc, Mar 06 2012


You'd have to grow them under stress, presumably. But if you apply continuous stress to growing multicellular biological thingys, generally they'll remodel to remove the stress. So, if you grew your nuts in a vice, you'd just get flat nuts, not nuts that went "sproing" when you took them out of the vice. Maybe you should insinuate a stoichiometric hydrogen-oxygen mixture into the space between nut-meat and shell. That way, the shell is in tension, but the meat is compressed, and you stand some chance of getting an intact nutmeat out of it. Either that or a thermonuclear reaction.

Coming soon, to a Halfbakery near you: thixotropic Prince Rupert orreries.
-- mouseposture, Mar 06 2012


So who here will volunteer to grow their nuts in a vice?
-- AntiQuark, Mar 07 2012


I've got a couple of big brass balls you could use, but only if my wife says it's okay.
-- Alterother, Mar 07 2012


Perhaps you could score fine lines in the surface of the nut shell to promote crack formation.
-- pocmloc, Mar 07 2012


//score fine lines in the surface of the nut shell to promote crack formation//

In general, stiff biological materials (bone, wood) have very sophisticated crack-stopping mechanisms, precisely to prevent this type of crack propagation. I would imagine that nut shells would have similar mechanisms.
-- MaxwellBuchanan, Mar 07 2012


//You are of course controlling the permeability of your nuts by coating them with a clear polyurethane varnish//
[hippo] I can quite honestly say, I for one have never attempted this, but it does sound the sort of tip that gets passed round in cyclist circles from time to time.
-- goff, Mar 07 2012


The varnish might get expensive. But consider: one could use ice! A coating of ice should make the interior gas-impermeable enough to allow this device to work.

If it does not on the first try, I am sure the project could be salvaged with some head-wagging and tut-tutting at the engineers from the comfort of the Armchair.

Once devised, in the televised version of the Halfbakery, the team would go on to use the device to open other things: bananas, oranges, jars of peanut butter, toothpaste, unpeeled shrimp, condom packages etc. Etc!
-- bungston, Mar 07 2012


//Etc!// [marked-for-tagline]
-- mouseposture, Mar 08 2012



random, halfbakery