Here’s how it works:
The bacteria eat lactic acid (a byproduct of fermentation)
They produce carbon dioxide gas as a result
The gas gets trapped in the soft, warm cheese
It forms bubbles — which become holes as the cheese firms up
Think of it like yeast in bread — but instead of rising, the cheese develops perfect little pockets of air.
And the size of the holes?
It depends on:
Temperature
Aging time
Moisture content
Even the cow’s diet
Too cold? No bubbles.
Too dry? Holes collapse.
Too much gas? Big, uneven eyes.
It’s a delicate balance — and Swiss cheesemakers have spent centuries perfecting it.
The Cow Connection – It Starts in the Pasture
Here’s how it works:
The bacteria eat lactic acid (a byproduct of fermentation)
They produce carbon dioxide gas as a result
The gas gets trapped in the soft, warm cheese
It forms bubbles — which become holes as the cheese firms up
Think of it like yeast in bread — but instead of rising, the cheese develops perfect little pockets of air.
And the size of the holes?
It depends on:
Temperature
Aging time
Moisture content
Even the cow’s diet
Too cold? No bubbles.
Too dry? Holes collapse.
Too much gas? Big, uneven eyes.
It’s a delicate balance — and Swiss cheesemakers have spent centuries perfecting it.
The Cow Connection – It Starts in the Pasture
The bacteria that create the holes?
They don’t just come from a lab.
They start in the grass.
Yes — the same grass cows eat in the lush Alpine meadows of Switzerland.
When cows graze, they ingest microbes from the soil and hay — including Propionibacterium.
These microbes end up in the milk — and from there, into the cheese.
In fact, traditional Emmentaler is made with raw milk — which preserves these natural cultures.
That’s why Swiss cheese made in other countries often has fewer or smaller holes — the microbes aren’t the same.
It’s terroir — not just for wine, but for cheese.
Why Not All “Swiss Cheese” Has Holes
see continuation on next page
