BERLIN — The mystery of Swiss cheese and its disappearing holes has been solved: The milk’s too clean.
A Swiss agricultural institute discovered that tiny specks of hay are responsible for the famous holes in cheeses like Emmentaler or Appenzeller. As milk matures into cheese these “microscopically small hay particles” help create the holes in the traditional Swiss cheese varieties.
The government-funded Agroscope Institute for Food Sciences and the Swiss Federal Laboratories for Materials Science and Technology said in a statement Thursday that the transition from age-old milking methods in barns to fully-automated, industrial milking systems had caused holes to decline during the last 15 years.
In a series of tests examining the ripening process over 130 days, scientists added different amounts of hay dust to the milk and discovered it allowed them to regulate the number of holes by using CT scans on the cheese.
The Journal of Dairy Science indicates that the previously held theory, which originated in 1917, said that the eyes in cheese are derived from a gaseous fermentation of the sugar of fresh curd, which is produced by bacteria or yeast.
