Why does Swiss cheese have holes?


In contrast to  what  you  may  been  told as a  child,  NO,  the  holes in cheese  are not made by mice  nibbling  away at  it. Cheese gets its hole-y appearance from the bacteria, which turns milk into cheese. These bacteria, once mixed with cow’s milk, turns it into curd.

The curd is  then  pressed and soaked in brine inside cheese mold’s, and later stored at high temperatures for it to ripen. This is when the bacteria starts its work, by consuming the lactic acid that is released during this process, and releasing carbon dioxide in the form of bubbles. These bubbles do not disappear, but instead form little air pockets, which results   in  the  holes  that  we  see  in  Swiss cheese.