how do they get holes in swiss cheese
The characteristic holes in Swiss cheese, also known as "eyes," are formed by carbon dioxide gas produced during the fermentation process. Here’s a simplified explanation of how they’re created:
- Cheese Production: Swiss cheese, such as Emmental or Gruyère, is made from cow’s milk. The milk is heated, and a starter culture is added to convert the milk sugar (lactose) into lactic acid.
- Fermentation: The lactic acid produced during fermentation lowers the pH of the milk, creating an environment that’s favorable for the growth of specific bacteria, like Propionibacterium freudenreichii.
- Carbon Dioxide Production: As these bacteria feed on the lactose, they produce carbon dioxide gas (CO2) as a byproduct. The CO2 gets trapped within the cheese, forming bubbles.
- Aging Process: The cheese is then aged, during which time the bacteria continue to produce CO2. The pressure inside the cheese wheel increases, causing the bubbles to expand and merge, forming larger holes or "eyes."
- Enzyme Breakdown: As the cheese ages, enzymes break down the casein proteins, making the cheese more pliable and allowing the holes to expand further.
- Final Shape: After several months of aging, the cheese wheel is removed from the aging cell, and the holes have reached their characteristic size and shape.
The size and distribution of the holes can vary depending on factors like the type of cheese, aging time, and bacterial cultures used. The holes in Swiss cheese are not only aesthetically pleasing, but they also contribute to the cheese’s unique flavor and texture.
