The little soft spots don’t penetrate into the center, where the coconut water is, though, at least not in a fresh coconut. I’ll be honest, I don’t know what the germination process is like, so I don’t know exactly when in the natural life cycle of a coconut the hull is breached, but it’s not breached when you buy it at the store or gather it on the beach, as long as you can still hear sloshing inside. You can put that water straight into someone’s vein for IV rehydration therapy, it’s sealed up so tight!
As usual IT DEPENDS! A young coconut with lots of milk will probably boil and blow out the ‘eyes’ first. An old coconut with little or no milk and lots of solid white may blow up or possibly leak off steam via the eyes. At worst it could rupture and hurl chunks of shell and white solids in all directions.
Recommend that The Hamster King buy an assortment of coconuts, build a sizeable campfire, run a series of experiments, and report back to the straight dope in a week or two! 
As I said, this is going to take a lot of beer.
Alert Mythbusters, imo.
This has all the makings of scarring injuries for Dopers. Subscribed.
What we need at this point is a musical montage of scientist in a lab, looking pensively at coconuts, tapping them with stainless steel mallets, shaking their heads and noting something on a clipboard.
Then various shots of failures to explode in the manner of “the right stuff” before fading the music out slowly to a single shot of a coconut resting in the centre of a roaring fire and the scientist huddled behind a blast wall.
and…action!
One argument against them exploding. No Utube video.
The physics/biology part of me has a guess as to the outcome but without experimentation it is just hypothesis. I suspect that the hull would not burn before creating steam - that is to say steam would be generated inside before hull integrity was lost no matter what context was used for the burn (even a propane torch for instance). Factoring in the two important elements of 1. heat insulation from the hull and 2. permeability of the hull I suspect that steam and pressure both would occur prior to burn-through - those hulls are thin, but dense. Depending on the rate at which the thing was heated (i.e. small campfire vs large campfire) I think an explosion is possible. With a small fire it is more probable that one of the three lil weak spots would give way and simply vent the pressure prior to major failure of the hull. In a large campfire or bonfire I suspect that steam would build very quickly once it started… and it might build so rapidly as to explode before venting through one of the little holes. I’d bet that in a large fire, hot hot hot bed of coals, the sucker would indeed explode.
Where are all the chemistry and physics guys when you need them…
(here is my best shot) IANACPG
Just like you can breifly hold a blowtorch to a paper cup full of water without starting a fire (the mass of water keepts the paper below its ignition temperature).
The hard shell of the coconut would quickly bleed heat into the fluid inside. The boiling point of coconut milk is most likely far below the actual burning temperature of the shell. This means until that fluid boils off it will be hard to burn through the coconut.
The big question is how perfect of a seal is the outer shell of the coconut. Once the fluid starts to boil, it either vents, or the internal pressure increases. IF it does not slowly leak out you should get a coconut to pop nicely. Problem is, it wont take much of a leak to vent enough steam to keep said coconut from bursting.
I agree. The most plausible explanation for why it’s not on YouTube is that the result is spectacularly boring.
Took me a minute but I think you’re onto something here. What we need to know now is how good a conductor of heat is coconut hull. I’m thinking your principle is sound, but that the hull is likely to combust before the heat sinks into the milk 1 quarter inch away. Contrast this to 1/32 inch of paper which puts the cup water in much closer proximity to the heat source.
Really, the best way to do this test is to fill a hollow, dried coconut with black powder and then see how long it takes for the hull to transfer sufficient heat to the internal contents to cause a noticeable combustion.
Then, if there’s anyone left alive they can approach a physics/chemistry person and hav them run whatever numbers those types like to run in cases like this.
I am a chemist.
I agree that heat will make it through the shell fairly quickly, but will take longer to go through the white meat. Thus, the shell could have a hole burned in it.
Bottom line? It is going to take a lot of beer to prove it will explode the lack of a Utube video not with standing.
I am definitely putting all my money on kaboom.
But I’m going with the traditionalish green coconut, on a very large pile of hot coals.
Take that back, actually, both a fresh green coconut in the husk, and a husked one just in the shell, heaping pile of hot, hot coals.
Kaboom!!!
Kabooom! (just when you thought it clearly wasn’t going to blow!)
I wonder about carefully putting a coconut soft spots up in a hot fire. Will we get a jet of coconut milk arcing out of the fire?
You guys beat me by a few hours, but I was going to suggest that the “youtube dumb stunt completeness theorem” ®™ comes close to guaranteeing that if there’s a dumb stunt within the technical & economic reach of backyard physicists or beered-up yokels, then there’s a video of it.
No youtube video; therefore no coconut explosion. Q.E.D.
But if anybody here does try it, make sure to set up a vid camera & have your next of kin upload it for our edification. Besides, that will further drive the dumb stunt completion theorem towards universal coverage.
I was camping on an island along the intercoastal waterway with a friend. The fire was smoldering, and we argued as to whose turn it was to find wood. He chucked a li’l capful of gas on the fire to get it flaring up: nothing. second capful: nothing. Poured a stream from the gas can: flame ran up the stream and lit the gas can, so he wheeled and threw it away from himself, resulting a tower of flame from the campfire, an arc of burning gas around the campfire and a second fire away from the camp where the can was.
We yelled, we screamed we ran around like maniacs.
Eventually I grabbed our shelter half and proceeded to put out the arc of flames and the second spot while he picked up the gas can with the stick and walked with it to the waters edge. I watched the little light in the burning spout bob down to the shore in the darkness (yes, an adult would have just capped it and been done.) I saw the arc in the sky gas can was flicked into the water. When the can hit the water it probably burst, and it certainly spread gas over the water, because then I saw a massive pillar of flame upon the sea, like God in the Old Testament, with my pal silhouetted in orange light dancing in terror on the shore.
We spent the night huddled without shelter (remember, the shelter halves put out the fires) in a campsite reeking of smoke and gasoline while coastguard searchlights swept over us as they looked for the wreckage of the exploding boat they had been called about.
Good times.
My brother has coconuts and a lighter. And his mum-in-law is in town, this sounds like a family project if there ever was one.
Album title!
Someone needs to notify Mythbusters. If anyone can make a coconut explode somehow it’ll be those guys! 
[nitpick] The stuff we’re hoping will make the coconut explode is coconut water not coconut milk. [/nitpick]
CMC fnord!
NTS Do not eat breakfast at Inigo Montoya’s, he takes the idea of Coco[del]a[/del] Bombs far, far, to literally.
Nitpick reply
* fabulism
* vignette
* gadabout
* meiosis
coconut milk
- 2 dictionary results
Quality Coconut Milk
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nutsonline.com/Coconut-Milk
3 Uses For Coconut Milk
Coconut And Its Amazing Benefits. The Latest Nutrition Advice!
lifescript.com
What Is Coconut Milk
All About What Is Coconut Milk What Is Coconut Milk in One Site!
peeplo.com/What+Is+Coconut+Milk
coconut milk
–noun
the clear, potable liquid contained within the young hollow seed of the coconut palm.
2.
the milky, potable but highly perishable liquid contained within the mature hollow coconut.
3.
the milky, potable liquid extracted from grated coconut meat by infusion with boiling water.
from http://dictionary.reference.com/browse/coconut+milk
I suspect both are in common usage.