What makes the holes in swiss cheese?
Swiss cheese is a cheese with many large holes. The holes are made by bacteria.
To make Swiss cheese, the cheese maker begins by adding special bacteria to fresh milk.
This is not the kind of bacteria that makes you sick. These are safe bacteria.
These cause the milk to sour, and this is known as “ripening.” When ripening has progressed to the proper stage, the cheese maker stirs in a substance called “rennet.” This makes the solid part of the milk, or curd, separate from the liquid part of the milk, or whey.
The soft lumps of curd are used to make the cheese. After the whey is drawn off, the soft curd is salted and pressed into round cakes, or wheels.
The wheels of Swiss cheese are then stored in warm curing cellars. As the cheese ages, or cures, bacteria produce a carbon dioxide gas which creates bubbles in the cheese.
The bubbles cannot escape, but remain in the form of the familiar holes. – Dick Rogers