We now move on to the process of harvesting oil from the sperm whale’s head. To understand this work properly, you first need to know the unique inner structure of a whale’s head.
Picture a sperm whale’s head as a solid, rectangular block. If you tilt it sideways, you can split it into two distinct solid sections.
The lower section is hard, bony tissue—it makes up the whale’s skull and jaws. The upper section is completely different: a soft, fatty mass with no bones at all. Its wide, flat front forms the broad, vertical forehead you see on a living sperm whale.
Now split that soft upper section horizontally right in the middle. You’ll get two nearly equal parts. A thick, tough layer of tendon naturally separates these two parts inside the whale’s head.
To be clear, this special section of the whale’s head is what sailors call a “quoin”—a old nautical term you won’t find in standard math textbooks. Unlike a simple wedge, a quoin tapers to a sharp edge from only one steep slanted side, not two.
The lower half of that soft upper section is known among whalers as the junk. It’s essentially a massive honeycomb packed full of oil. Tough, stretchy white fibers crisscross every inch of this part, creating tens of thousands of tiny oil-filled cells.
The upper half is far more valuable. Whalers fittingly call it the Case, and it’s basically the sperm whale’s version of the famous Heidelberg Wine Barrel.
Just like the old German wine barrel was carved with intricate patterns on its front, the whale’s folded, textured forehead is covered in strange, natural ridges and markings—like decorative carvings adorning this giant organic barrel.
And where the Heidelberg barrel held the finest wine from the Rhine River valleys, the whale’s Case holds the most precious substance in its entire body: pure, clear, sweet-smelling spermaceti oil.
No other part of the whale produces this unrefined, perfect spermaceti. While it stays completely liquid inside the living whale, it changes quickly after death. Once exposed to open air, it starts to harden, growing delicate, crystal-like formations—thin and fragile, just like the first faint ice crystals forming on still water.
A full-grown large sperm whale’s Case can hold roughly five hundred gallons of spermaceti. But whalers rarely collect every drop. This work is incredibly delicate. A huge amount of the oil spills, leaks, drips, or is otherwise lost entirely during the tricky harvesting process.
No one knows what fine, luxurious material lined the inside of the original Heidelberg Wine Barrel. But whatever it was, it could never compare to the silky, pearlescent membrane lining the whale’s Case. It’s as soft and smooth as the finest fur coat lining.
This whale’s natural oil barrel stretches the entire length of the top of its head. A sperm whale’s head makes up one-third of its total body length. A full-sized whale can reach eighty feet long, meaning its oil-filled Case runs more than twenty-six feet deep.
Think about how whalers remove a whale’s head first. Their blades cut dangerously close to the exact spot where they’ll later pry open the Case to harvest the spermaceti.
“One wrong move here, and we ruin everything,” any seasoned whaler will tell you.
A careless, early slice can tear open the precious oil chamber, spilling all that priceless spermaceti to waste.
Once severed, the whale’s head is hoisted high out of the water. Massive cutting tackle and a tangled web of thick hemp ropes hold it suspended in place beside the ship.
With all that explained, we can now turn to the incredible, risky process of tapping open the sperm whale’s giant natural barrel and extracting its rare, valuable oil.