The widely accepted belief carbon dioxide bubbles cause the holes that are the hallmark of Swiss cheese is flat out wrong.
A study triggered by a puzzling and persistent reduction in the number of holes in Swiss cheeses has revealed the real reason for the intriguing holes in this type of cheese.
The real cause of these holes is the hay fed to cows.
The holes are formed by the amount of microscopically small hay particles that make their way into cows' milk. The size of the holes depends on the amount of hay and other contaminants present in the buckets used to collect milk the traditional way.
This finding overturns a century of conventional wisdom that said the holes are caused by the release of carbon dioxide by bacteria within the cheese. The belief CO2 is the cause was first posited by American scientist William Clark in 1917.
Researchers said as microscopically small hay particles fall into buckets, they create tiny vacuoles (a small cavity or space) that grow in size as the cheese matures.
To confirm this theory, researchers added hay dust in small amounts to samples of milk. The milk was then processed into cheese over 130 days.
Researchers found out they were able to control the number of holes created in the cheese by varying the amount of hay dust in the milk.
Their findings solve a problem posed by the notable reduction in the number of holes in Swiss cheese produced during the last decade and a half. It seems the use of closed, automated systems that milk cows using hoses that don't expose the milk to hay dust in the air has meant fewer holes are present in cheese.
Milking machines "completely did away with the presence of tiny hay particles in the milk," said Regis Nyffeler, a spokesman for Agroscope, a Swiss agricultural agency that conducted an investigation of the conditions leading to the development of holes in some forms of Swiss cheese, according to Tech Times.
Holes in Swiss cheese are known as "yes". Cheese-makers refer to any cheese without holes as "blind."
Swiss cheese is the American name for holed cheeses similar to those made in Switzerland such as Emmental. Popular American Swiss cheeses are Baby Swiss and Lacy.