Bushra Griffith
Swiss cheese is one of the most well-known types of cheese in the world, distinguished by its extra-large holes, also known as eyes, and its unique flavour. The holes in Swiss cheese have long been a source of fascination and speculation, with a variety of theories proposed over the years to explain their formation. While it was once believed that the holes were caused by carbon dioxide released by bacteria, recent studies have revealed a different origin. So, how are these holes formed, and why have they been getting smaller over time?
| Characteristics | Values |
|---|---|
| Reason for holes | Carbon dioxide gas released by bacteria, or microscopic bits of hay in the milk |
| Proper name | Emmentaler |
| Region of origin | Emmental region of Switzerland |
| Type of bacteria | Propionibacter shermani |
| Modern hole size | Smaller due to modern milking methods |
Explore related products
What You'll Learn
Hay particles in milk
The presence of hay particles in milk is one of the reasons for the formation of holes in Swiss cheese. The process of making Swiss cheese involves the addition of a starter culture of bacteria, specifically Propionibacter shermani, to the milk at the beginning of the cheesemaking process. This bacteria consumes lactic acid and releases carbon dioxide gas bubbles, which become trapped in the cheese's rind and gradually form holes, often referred to as "eyes".
While the role of bacteria in hole formation has been widely recognized, the contribution of hay particles in milk has also been identified. Agroscope, a Swiss agricultural institute, attributed the presence of holes in Swiss cheese to microscopically small hay particles falling into the buckets used for collecting milk. As the cheese matures, these hay particles develop into larger holes. The likelihood of hay particles contaminating the milk is higher when cheese is produced in barns using open buckets, as was traditionally done.
The impact of hay particles on the structure of the cheese curd is significant. The hay particles create weaknesses in the curd structure, allowing gas to form and expand, resulting in the characteristic holes. This phenomenon is not limited to hay particles; any particulate matter can have a similar effect. The size and number of holes in Swiss cheese varieties such as Emmentaler, Appenzeller, and Emmental are influenced by the amount of hay particles introduced during the milk collection process.
The modernization of dairy farming practices, including the adoption of more automated and antiseptic milking methods, has resulted in a decrease in the number and size of holes in Swiss cheese. The use of modern containers during milking has reduced the likelihood of hay particles contaminating the milk, leading to smaller and less frequent holes in the final product. This shift in cheesemaking techniques has contributed to the observed changes in the appearance of Swiss cheese over the years.
Cache Valley Cheese: A Local Treasure, Made in the USA
You may want to see also
Gas formation
The holes in Swiss cheese, also known as "eyes", are caused by gas formation during the cheese-making process. This gas formation is a result of the presence of microscopic hay particles in the milk used to make the cheese. The hay particles create weaknesses in the structure of the curd, allowing gas to form and expand, eventually creating the holes or "eyes" characteristic of Swiss cheese.
The specific type of bacteria added to the milk at the start of cheesemaking, known as Propionibacter shermani, plays a crucial role in gas formation. This bacteria consumes lactic acid and releases carbon dioxide gas in the form of bubbles. As the cheese ages, these bubbles become trapped within the rind and gradually form the holes. Cheesemakers can control the size of the holes by adjusting factors such as milk temperature, acidity, and aging time.
The traditional method of cheese-making in barns using open buckets contributed to the presence of hay particles in the milk. However, with the modernization of dairy farms and the adoption of more automated and antiseptic milking methods, the incidence of hay particles in the milk has decreased. As a result, the size and number of holes in Swiss cheeses have also reduced over time.
The relationship between the flavour of the cheese and the size of the eyes is worth noting. Larger holes indicate a more intense and developed flavour, resulting from the increased presence of flavour-enhancing bacteria during the aging process. This correlation may explain the difference in taste between American-produced Swiss cheese, known for its smaller air pockets and milder flavour, and its European counterpart, which tends to have larger holes and a richer, nuttier taste.
Goat Milk Cheeses: Exploring Varieties and Flavors
You may want to see also
Modern milking methods
Traditionally, cheese was made in barns using open buckets, which meant that hay particles could easily fall into the collected milk. This would cause weaknesses in the structure of the curd, allowing gas to form and create holes. Modern milking methods, however, have largely eliminated this issue by reducing the likelihood of hay coming into contact with the milk.
The change in milking methods has also impacted the type of bacteria present in the milk, which has contributed to the reduction in holes. Previously, the bacteria present in Swiss cheese wheels would produce carbon dioxide, which would form bubbles and eventually pop, creating holes. With fewer hay particles to feed on, the bacteria responsible for producing carbon dioxide have decreased, resulting in fewer holes.
Additionally, modern milking practices often involve extracting milk using more closed and controlled systems, which help prevent the entry of unwanted particles like hay. These methods include the use of sealed containers, pipes, and filters, which minimize the risk of hay contamination.
While the reduction in holes may be seen as a positive development by some, others may view it as a loss of the traditional characteristics of Swiss cheese. The presence of holes, or "eyes," has long been associated with the unique identity of Swiss cheese, and their gradual disappearance could be seen as a departure from the classic cheese-making process.
Kiri Cheese: Ingredients and Creamy Texture Secrets
You may want to see also
Explore related products
Carbon dioxide
The holes in Swiss cheese, also known as "eyes", are caused by the presence of carbon dioxide and hay particles. This carbon dioxide is produced by bacteria during the fermentation process.
In 1917, American scientist William Clark hypothesised that the bacteria present in milk used for Swiss cheese production released carbon dioxide, and this gas formation led to the creation of the holes. Clark's theory has a scientific basis, but it is not entirely accurate. More recent research by Swiss scientists from the Agroscope Institute for Food Sciences and the Swiss Federal Laboratories for Materials Science and Technology suggests that the holes are caused by a combination of carbon dioxide and hay particles.
During the fermentation process, bacterial acids, especially propionic and lactic acids, lead to the release of carbon dioxide, creating bubbles that become trapped inside the cheese. The concentration of carbon dioxide, along with other factors like fat, bacteria, and hay particles, determines the size and shape of the holes in the cheese.
Cheesemakers can control the hole size and shape by adjusting these factors, ensuring consistent and desirable "eyes" in their Swiss cheese products. The production of carbon dioxide by bacteria is crucial to achieving the desired holey-ness in Swiss cheese.
Cheese Curls: Unraveling the Ingredients of This Snack
You may want to see also
Propionibacter shermani bacteria
Propionibacter shermani is a bacterium from the Propionibacterium genus, which is divided into two groups based on habitat: skin (acnes) and classical (dairy). The Propionibacterium genus is a major source of valuable metabolites, such as propionic acid, vitamin B12, bacteriocin, and trehalose. Propionibacter shermani, in particular, is responsible for the ripening of Swiss cheese and the production of its characteristic taste and large gas bubbles. It is added during the production of certain cheeses, such as Emmental and Leerdammer.
The process of creating holes in Swiss cheese, specifically, starts with the presence of microscopically small hay particles in the milk used for cheesemaking. As the cheese matures, these hay particles develop into larger holes. This process is influenced by the presence of Propionibacter shermani bacteria, which produce propionic acid through fermentation. The propionic acid fermentation results in the release of aromatic carbon dioxide, forming bubbles that contribute to the hole formation.
The role of Propionibacter shermani in Swiss cheese production extends beyond hole formation. It is a key contributor to the distinctive flavour of Swiss cheese. The bacterial culture produces metabolites, including propionic acid, that impart a unique taste to the cheese. Additionally, the gas bubbles created by the bacteria's metabolic activity contribute to the texture and overall sensory experience of the final product.
Furthermore, Propionibacter shermani has been studied for its potential health benefits. Research has shown that this subspecies can induce apoptosis, or programmed cell death, of colon cancer cells. This property is attributed to the production of propionate and acetate by the bacteria. As a result, there has been interest in using Propionibacter shermani as a health-promoting additive in certain types of cheese, such as Feta-type cheese.
In conclusion, Propionibacter shermani plays a crucial role in the development of holes in Swiss cheese through its metabolic activity and interaction with hay particles. Additionally, it contributes to the flavour and texture of the cheese, making it an important microorganism in the cheesemaking process and a potential health-promoting additive.
Fresh Mozzarella Cheese: A Simple Milk and Rennet Recipe
You may want to see also
Frequently asked questions
The holes in Swiss cheese, also known as "eyes", are caused by tiny bits of hay that find their way into the milk during the collection process. These hay particles cause a weakness in the structure of the curd, allowing gas to form and create the holes as the cheese ages.
The size of the holes has decreased due to the modernization of dairy farms. As milking methods have become more automated and hygienic, fewer hay particles contaminate the milk.
Swiss cheese is a style of cheese that originated in the Emmental region of Switzerland. It is made by adding a starter culture of bacteria to the milk at the beginning of the cheesemaking process. This bacteria, called Propionibacter shermani, consumes lactic acid and releases carbon dioxide gas bubbles, which become trapped in the cheese and slowly form holes.
Yes, cheesemakers can control the size of the holes by altering the temperature, acidity, or aging time of the milk.
No, not all Swiss cheeses have holes. The presence of holes depends on the specific type of cheese and the cheesemaking process. For example, Gruyère, a Swiss cheese, may or may not have holes.
