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Food & Lifestyle
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Swiss Cheese Gets Its Holes Back: A 2025 Court Ruling Reverses a Decade of Purity
Increased hygiene caused Swiss cheese holes to disappear. A 2015 study revealed microscopic hay particles were the secret ingredient. Now, in a landmark 2025 ruling, the Swiss court has approved adding hay powder to milk, scientifically restoring the iconic eyes to traditional cheese.
For centuries, the iconic holes—or “eyes”—in Swiss cheese were a happy accident, a hallmark of traditional cheesemaking. But in the early 2000s, cheesemakers noticed a troubling trend: the eyes were shrinking, and in some cases, disappearing entirely. The culprit, ironically, was progress. Now, in a landmark 2025 decision, the Swiss Federal Administrative Court has officially sanctioned putting a piece of the farm back into the cheese, all in the name of restoring its classic, holey appearance.
The Case of the Disappearing Holes
For over a decade, the mystery of the vanishing holes perplexed Swiss cheesemakers. Their famous Emmental and Appenzeller cheeses, known for their distinctive eyes, were increasingly coming out “blind.” For years, the common understanding was that the holes were simply formed by carbon dioxide gas released by bacteria, such as Propionibacterium freudenreichii, as the cheese aged. While true, this didn't explain why they were suddenly disappearing from cheeses made with the same cultures and methods.
The answer, it turned out, was cleanliness. As dairy farms modernized, they moved from traditional open-bucket milking to automated, sealed systems. These new methods were far more hygienic, preventing contaminants from entering the milk. Unbeknownst to anyone, they had cleaned out the secret ingredient responsible for creating the perfect cheese eye.
A Scientific Breakthrough: The Secret in the Hay
The mystery was finally solved in 2015 by scientists at Agroscope, Switzerland’s national center for agricultural research. Their study revealed that the formation of eyes depended on microscopic hay particles finding their way into the milk. These tiny specks of hay act as “nucleation sites,” giving the CO2 gas produced by the bacteria a place to gather and form a bubble. Without these nuclei, the gas would simply dissipate, resulting in a cheese with few, if any, holes.
The disappearance of the traditional bucket used during milking was the major cause of the mystery. It left microscopic hay particles in the milk which helped the holes to form.
This discovery explained everything. The ultra-hygienic, closed-system milking parlors were so effective that they filtered out the essential hay dust. In making the milk purer, they had inadvertently stripped it of the very element that gave Swiss cheese its character.
The 2025 Ruling: Tradition Through Technology
This scientific breakthrough created a new dilemma. How could cheesemakers reintroduce the holes without compromising modern hygiene standards? For years, debate raged between food safety regulators and producers seeking to preserve their cultural heritage. This culminated in the recent 2025 court case, which weighed the definition of a “pure” ingredient against the traditional character of a protected product.
In a victory for cheesemakers, the court approved the controlled addition of sterilized “hay flower powder” to the milk. This allows producers to precisely dose the milk with the necessary nuclei to control the number and size of the eyes, turning an age-old accident into a modern science. The ruling is a fascinating blend of old and new—using technology to perfectly replicate a flaw of the past. So the next time you enjoy a slice of perfectly holey Swiss cheese, you can thank a dash of science and a court that agreed that sometimes, a little bit of “dirt” is a very good thing.