Why does Swiss cheese have holes?
That’s easy. The culprit is (let’s say it all together now) Propionibacter shermani. All cheese is made with the help of bacteria, or more specifically, a bacteria-based culture. These “starter organisms” are added to milk and are one of the major factors that help determine the type of cheese that you end up with. For Swiss cheese, S. thermophilus and Lactobacillus start the process, producing acid and using lactose from milk as an energy source. Then the mixture is placed in a warm room, which favors the growth of P. shermanii. That uses the lactic acid to produce carbon dioxide and propionic acid. Carbon dioxide makes the holes by expanding into bubbles of gas, and propionic acid helps produce Swiss cheese’s characteristic flavor. The size of the holes can be controlled by varying several factors: acidity, temperature and curing time. Because of this, food scientists say cheese-making is a combination of art and science. It takes a certain expertise to get conditions “just right.” K
Swiss cheese or fromage Suisse has holes in it due to the fermentation process which creates the cheese. Cheese is made by introducing bacteria to milk, which begins to curdle as the bacteria eat and produce lactic acid. Another byproduct of the digestion process is often carbon dioxide gas, which in some cheeses is trapped inside the rind, forming bubbles in the finished cheese product. Swiss cheese is the most well known for this, with some types of Swiss cheese having holes as large as walnuts. A number of cheeses are marketed under the name of Swiss cheese. The true Swiss cheese is Swiss Emmental or Emmentaler, produced in a particular part of Switzerland. Emmental has a protected origin designation, which means that only cheese prepared in that area of Switzerland, and in a certain way, can be labeled Emmental. Swiss Emmental has the creamy texture and large holes most consumers associate with “Swiss cheese.” Other holey cheese is made in various parts of the world and labeled as
But the air/cheese ratio will be changing soon. It seems Swiss cheese with big holes fouls up modern slicing machinery. So the industry is now asking that the regulations for Grade A Swiss be revised to make the average hole only three-eighths of an inch in diameter–one-quarter the area it is today. (Small-hole Swiss is now classified as Grade B, which commands a lesser price.
Propionibacter shermani is one of the three types of bacteria used to make Swiss cheese, and it’s responsible for the cheese’s distinctive holes. Once P. shermani is added to the cheese mixture and warmed, bubbles of carbon dioxide form. These bubbles become holes in the final product. Cheesemakers can control the size of the holes by changing the acidity, temperature, and curing time of the mixture. Incidentally, those holes are technically called “eyes,” and the proper Swiss name for the cheese is Emmentaler (also spelled Emmental or Emmenthaler).
