I’ll never forget the first time I stood in a cheese cave in Emmental, Switzerland.
The air was cool and thick with the scent of aging milk.
Stone walls glistened with moisture.
And rows of massive, golden wheels of cheese rested in quiet rows — like sleeping giants.
A fourth-generation cheesemaker tapped one gently with a small metal hammer — tap, tap, tap — listening like a doctor with a stethoscope.
“The holes tell us the cheese is breathing,” he said.
I nodded, pretending I understood.
But inside, I was thinking:
“Cheese… breathing?”
It sounded poetic.
Mysterious.
Maybe even a little made up.
But as it turns out?
He was telling the truth.
And the real reason Swiss cheese has holes — those iconic round “eyes” — isn’t because of mice, myths, or magic.
It’s science.
Bacteria.
And a little bit of cow burp.
Let’s explore the fascinating truth behind the most famous feature in cheese.
🧫 The Science Behind the Holes – It’s All About Bacteria
The holes in Emmentaler (the real Swiss cheese with holes) are called eyes — and they’re formed by bacteria during fermentation.
But not just any bacteria.
The star of the show is Propionibacterium freudenreichii — a friendly microbe added to the milk during cheesemaking.
Here’s how it works:
