New Issue: Orbital Catastrophe Ahead? Read Now

Number and Size of Swiss Cheese Holes Can Be Programmed

Holes in Swiss cheese finally give up their gaseous secrets

Join Our Community of Science Lovers!

About two decades ago Swiss geneticists were trying to figure out how a few vital genes exerted master control over the development of fruit flies. In the course of their work, they managed to get a fly to grow numerous eyes all over its body. Sure, the information is crucial for our understanding of how an individual changes from a single fertilized egg into a differentiated organism, but little to no market exists for the disturbing Drosophila.

This year a different group of Swiss scientists figured out another vexing eye problem: exactly what causes the formation and development of the numerous eyes (what we laypeople call holes) in Emmental (what we laypeople call Swiss) cheese. The information is crucial for our understanding of how to create cheeses with the right number and size of holes. And billions of dollars in revenues are at cheese-stake in quiches, fondues and sandwiches alone.

To give you an idea of the scope of the Emmental effort, it took 13 researchers at three different Swiss facilities—Agroscope's Institute for Food Sciences, Empa's Center for X-ray Analytics and the Lucerne University of Applied Sciences and Arts—to come up with the study, which was published in the International Dairy Journal with the title “Mechanism and Control of the Eye Formation in Cheese.” The history is a little unclear, but it looks like it took only one guy, the late Tom Nugent, coach at the Virginia Military Institute around 1950, to come up with the mechanism and control of the I-formation in football.


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


The connection between the two disciplines can be seen in Green Bay, Wis., where Packers fans proudly recognize their state's dairy prowess by wearing large wedges of faux cheese on their heads. Cheddar may outsell Swiss at the grocery store, but the hat cheese, like the head wearing it at the frozen tundra of Lambeau Field, clearly has holes in it.

The journal article points out that “the size of the eyes of first-quality cheese should be between the size of a cherry … and a walnut.” (To use language more familiar to this magazine's readership, that's between the size of a large ureterovesical cyst and an adult's prostate.) But different people prize different eyes. “Italian consumers prefer Emmental cheese with walnut-sized eyes,” the study authors note, “whereas commercial manufacturers of sliced cheeses ask for cheese with smaller eyes and higher eye numbers.” Thus, you want to control the eyes.

Bacteria do most of the work in cheese making. They produce carbon dioxide gas, forcing the expansion of eyes. If you manage to make what is actually called blind Swiss cheese—no eyes at all—the gas buildup causes slits or splits that reduce quality. Besides, Swiss cheese without holes is a semiotic disaster.

But what makes an eye start to form? Cheese whizzes assumed for the past century that some tiny particle acted akin to the seed of a dust mote, around which a drop of rain forms in a vapor-saturated air mass. The Swiss scientists thus thought, Hay! Dairy farms have lots of hay, and hay dust “could act as highly effective eye nuclei.”

They mixed various amounts of hay particles into embryonic Emmentals and found that they could “control the number ... and size of the eyes in cheese in a dose-dependent manner.” The data should open the eyes of cheese makers worldwide, figuratively and possibly literally.

The intrepid investigators also unintentionally solved a problem that's been bothering Swiss cheese fans: over the past few decades the holes have been getting fewer and smaller. Now we can surmise that better hygienic conditions have been limiting contamination by plant particulates. The result has been the counterproductive reduction in the size and frequency of the holes. In other words, when it comes to cheese, there are none so blind as those that will not seed.

Steve Mirsky was the winner of a Twist contest in 1962, for which he received three crayons and three pieces of construction paper. It remains his most prestigious award.

More by Steve Mirsky
Scientific American Magazine Vol 313 Issue 2This article was published with the title “The Cheese Eyes Have It” in Scientific American Magazine Vol. 313 No. 2 (), p. 84
doi:10.1038/scientificamerican0815-84

Subscribe to Support Independent Journalism

Great science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.

When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.

Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber

Thank you,

Jeanna Bryner, Editor in Chief, Scientific American

Subscribe