Emmental: a hole needs somewhere to begin

A slice of Emmental shows what is missing, but those empty spaces tell a story. During ripening, fermentation produces carbon dioxide. The gas collects in cavities that become the cheese’s eyes. Emmentaler AOP’s producers’ organisation describes this stage in its production information. The holes are not cut out afterwards: they grow while the wheel changes, with microorganisms contributing to the process through their activity inside the cheese. [1]

Producing gas and starting a cavity are two separate problems, however. In its release of 28 May 2015, Agroscope clarified that tiny plant particles can provide starting points, while bacteria produce the carbon dioxide. Hay particles therefore do not replace fermentation. Their structure can hold small air bubbles, which expand as gas enters them. Mixing up these roles removes half of the explanation of how the visible holes form. [2]

A test described by Agroscope on 23 March 2026 used synthetic fibres and small tubes with controlled cavities to investigate this mechanism. The experimental cheeses were not intended for consumption. Observations supported the role of small cavities containing trapped air as starting points for eyes. This was laboratory research, not a recipe: the experimental materials made the structures being studied easier to recognise and compare with one another. [3]

Here is an editorial mental model. Imagine a plan of a room with a few small circles already marked on it. Adding more circles around the original ones shows where larger groups might develop. In our drawing, the starting points represent places where gas can collect, rather than whatever produces it. The comparison separates two jobs; it does not reproduce the sizes, materials or forces inside real cheese. [2][3]

The result is also assessed using specific criteria. The producers’ organisation includes eyes among the features considered when grading wheels, alongside the cheese body, flavour and other characteristics. A visually attractive slice therefore cannot describe the whole product. Our interest is in the criterion, rather than a commercial judgment: the number and arrangement of cavities form part of a process that cheesemakers work to control. [4]

This explanation should not be extended to every gap in every food. Agroscope also stresses that milk hygiene remains essential: simply calling microscopic particles dirt is misleading. In our exercise, we could draw a crack and ask why it differs from a rounded eye. That would be a question to investigate, not a diagnosis of the slice in front of us. Observing a shape can begin an investigation; it cannot replace one. [2]