Why Does Swiss Cheese Have Holes—And What If They Disappeared Forever?

The Great Hole-y Cheese Conundrum: It’s Not Magic

Put down that magnifying glass and step away from the secret agent movies. The question why does Swiss cheese have holes is not a government conspiracy, a mouse intention, or a failed farmer’s dream. In fact, it’s a tale peppered with bacteria, sneeze-worthy hay, unsolved international mysteries, and a dash of Swiss stubbornness.

Most of us—let’s be honest—simply take those little craters for granted, never pausing to wonder if perhaps the cheese itself was in a tragic meteoric incident. But the truth? It’s all about science, and it’s far funnier, weirder, and more dramatic than you can possibly imagine.

Bacteria: The Flatulent Chefs of Cheese

Grab your monocle. The primary architects of Swiss cheese’s signature aesthetic are bacteria known as Propionibacterium freudenreichii subsp. shermanii—a bacterium so delightful they practically named it twice. Not as famous as the Kardashians, but equally capable of producing air bubbles under pressure.

Here’s what happens: during the cheese’s grand spa holiday (also known as the ripening stage), these bacteria eat up lactic acid like it’s hot fondue at a winter gathering, and as they feast, they emit carbon dioxide. This playful gas comes together in pockets, giving the cheese those famous holes. You may call them bubbles, the Swiss call them "eyes," and a cheese scientist will call them case studies in microbial farting artistry.

But Wait, Why Hay?

Around 2015, cheesemakers and scientists discovered that those holes (a.k.a. eyes) started to disappear mysteriously in modern times. Swiss cheese was going bald! This was a calamity of international proportions (at least in Switzerland and every brunch spot with a 'classic' deli sandwich).

What triggered the Houdini act? Modern sanitation, as it turns out, was the culprit. Traditional cheesemaking in the bucolic Swiss Alps involved a haphazard splattering of hay dust—yes, actual microscopic flecks of hay—drifting from barn to cheese vat. That innocent debris acted as a starter-rocket for cheese gas bubbles to cluster and form holes.

In sparkling clinical facilities free of old hay, holes simply fizzled away, leaving the cheese with the personality of a government tax form.

Does Hole-less Swiss Cheese Even Count?

You might ask, in genuine existential confusion, whether a holeless block of Swiss still technically counts as 'Swiss cheese.' That conundrum actually led to minor identity crises in the Swiss dairy world (and more than a few debates over lunch). Turns out: the law, your grandma’s recipes, and the entire marketing department demand holes as proof of authenticity.

In fact, a slice of Emmental or Appenzeller without eyes is called "blind cheese"—as if it’s been cursed to never bask in the light of daylight streamed through its gaseous tunnels.

Hole-Size Politics: When Big Cheese Decided Enough Was Enough

Not all holes are created equal. The Swiss, being Swiss, measure and regulate the size, number, and quality of these cheese eyes—because if you can’t count your bubbles, can you even call yourself a cheese aficionado?

• Big holes are loved in Switzerland, but they can be a total sandwich disaster for Americans. (Nothing says 'soggy salad chaos' like your mustard falling through the Alps.)
• Regulations require a specific number of holes per square inch, like a quirky food sudoku.
• If your cheese is too “hole-y,” you’re legally in trouble—too few, and it’s cheese jail for you!

Cultural Reverberations: International Cheese-Identity Crisis

When Swiss cheese traveled abroad (sometimes called Emmentaler, sometimes "How Do I Pronounce This?"), it picked up many imitators. The American 'Swiss cheese' you throw on your burger doesn’t always follow the Hay Code, which explains why its holes are a bit more…non-committal.

Meanwhile, in Switzerland, holes equal prestige, time, and proof that the cheese wasn’t just pressed out by robots. In France and Germany, similar cheeses might have only partial holes, giving rise to arguments up there with ‘who really invented French fries?’

Pop Culture and Animated Rodents: Are Mice to Blame?

Somewhere along the line, pop culture decided if something is full of holes, it must be for mice. Tom and Jerry, Disney, and every mouse caricature from the 1920’s onwards have perpetuated the myth that mice specifically prefer holey cheese. There’s absolutely no scientific proof for this. In reality, cheese is hardly a mouse's first pick for dinner—a mouse’s real ideal dinner plate consists of grains, fruit, and if your luck’s rotten, your wallpaper glue.

The next time you see a cartoon mouse gleefully sprinting off with a wedge of Swiss, just remember: the holes are not made for mice to sneak through, but for gas to escape. In other words, the only real burrowing here is done by bacteria.

The “Eyes” Have It: What If We Lose the Holes Forever?

If ongoing cleanliness continues to wipe out every last hay mote, would Swiss cheese go blind forever? It’s a future so dystopian even Orwell might cringe—cheese blocks with all the charisma of a cinder block.

“Blind” Swiss would confuse consumers, irritate purists, and put the sandwich-topper industry in a full meltdown. Not to mention, without the whimsical peek-through holes, how could you possibly accessorize your Instagram charcuterie board?

Fortunately, scientists can add a little hay dust or tweak the bacteria to bring back the party. The future of hole-y cheese might come down to bioengineers wearing hairnets and wielding ultra-pure hay wands. Welcome to 21st-century cheesecraft.

Case Study: Cheeses Who Wanted Holes But Never Got Them

Before you feel sorry for the Swiss, consider the other cheeses who almost made it… but didn’t. Cheddar, Gouda, and even Brie contain bacteria and undergo ripening, but their starters just don’t pass gas in the right way (much like that awkward relative after Thanksgiving). The specific bacteria in these cheeses do not produce enough CO₂, nor do they require our beloved hay dust. The result? Solid cheese, forever denied the right to be peeped through by toddlers—or grandmas at family reunions.

Is There a Hole-to-Flavour Ratio?

It’s not all for show. Those cavities, where bubbles once lingered, subtly tweak the moisture and aging process, making Swiss cheese slightly nuttier, with a texture famoulsy described as 'springy.' No holes would mean denser, sometimes less interesting cheese. This, obviously, would be a tragedy for brunches, Reuben sandwiches, and anyone who enjoys poking their pinky through dairy products for TikTok likes.

The Other Side: Why Would Cheese Makers Want Fewer Holes?

Besides sticky-fingered children using slices as cheese binoculars, there are industrial reasons for sometimes limiting eyes. Big holes = sandwich trouble. Fine slicing machinery goes bonkers when confronted with a void half the size of a coin. Some cheesemakers intentionally restrict that classic Swiss gas just to keep lunch meat slicers from sobbing in despair.

How People React to Hole-y Cheese

If you think the world’s crises are wild, try serving a European 'holeless' Swiss cheese to a crowd used to the real deal. Jaws drop. Swiss grandmas tsk. Children speculate on portals to cheese dimensions. And somewhere a marketer loses their mind recalibrating photos for next year’s cheese calendars.

For those who grew up with holey cheese, it’s more than food. It’s a memory, a testament to 'how things used to be'—back when microbes farted freely and nobody cared if their kitchen counter was lightly dusted with hay.

International Comparisons: Do Other Cheeses Have Eyes?

Curiously, 'eyes' aren’t just Swiss territory. Maasdam, Jarlsberg, and Leerdammer—cheeses from the Netherlands and Norway—all sport various-sized holes thanks to their own varieties of gas-generating bacteria. American Swiss is famous for having smaller, more bashful holes, like a cheese that’s just a little socially awkward. (Can relate.)

Yet none compete with the wild, cavernous craters in authentic Emmentaler. These holes are as symbolic to Swiss culture as yodeling and accidentally losing tourists on Alpine trails.

Myths Pop Culture Still Can’t Shake

Despite everything, many still think the holes are either caused by mice, injected with special air guns, or the result of gouging gone wrong. Others believe the more holes, the better (tell that to a deli slicer). Explaining the scientific absurdity of all of this to your uncle at Thanksgiving is a service to the truth—and likely an excellent way to get out of doing the dishes.

Cheese in Evolutionary Perspective

Centuries ago, nobody cared about holes. Cheese was all about calories, not Insta aesthetics. But as standards rose—and cheesemaking moved from dark, dusty barns to high-tech labs—holes became a signature of craftsmanship. That little window on your sandwich? It’s the lasting echo of a thousand years of bacteria blowing tiny kisses into your lunch.

So next time you marvel at a slice of carbohydrate joy topped with holey Swiss, remember: it’s a work of time, microbes, and a little old-school dirt. The future may be cleaner, but the best stories definitely still come with a few holes in them.

Oops, History Lied Again

One of the biggest misconceptions swirling around Swiss cheese is that the iconic holes are made for mice, or worse, by mice, as if every cheese wheel was a Tom & Jerry set waiting to happen. Others think cheesemakers punch holes using mechanical gadgets—a cheese doughnut process—making Swiss cheese the carb-heavy version of a bagel. The actual answer is much less Hollywood: those holes (‘eyes’) are the natural result of specific bacteria (Propionibacterium freudenreichii subsp. shermanii) digesting lactic acid and farting out carbon dioxide, which forms gas bubbles inside the cheese. Another justice-for-bacteria moment: even the people who suspect ‘bacteria’ rarely realize how important environmental hay dust was historically in determining hole size and regularity. And, incredibly, many also assume that more holes means better quality when in fact too many (or too few) holes can get cheesemakers in regulatory hot water in Switzerland, the world’s cheese-perfectionist capital. So, holey cheese isn’t a rodent conspiracy, an act of sabotage, nor a mark of quality by sheer crater-count—it’s a marvel of microbial engineering, with a little help from old-school farming dust. The truth is cheesier and stinkier than fiction!