Many of us have looked at a piece of Swiss cheese with holes and thought, "What's up with that?" These holes are actually called as eyes.
At the start of making cheese, the milk is heated to kill any harmful bacteria, and then a starter culture is added. This helpful bacteria breaks down the milk.
Propionibacter shermani is the type of bacteria used to make Swiss cheese. It eats the lactic acid in milk and gives off bubbles of carbon dioxide gas.
The holes in Swiss cheese are made by these bubbles. The size of the holes in Swiss cheese depends on how long it spends in the curing facility.
Workman claims that, like many other food characteristics, the "holes" in Swiss cheese are a topic of discussion when it comes to the cheese's taste.
"In my opinion, the holes don't add much to the flavor. But, something went wrong during the manufacturing process if you have a blind Swiss," explains Workman.
In case it wasn't clear, a blind Swiss is a Swiss Cheese that lacks holes or eyes, rendering it effectively blind and so unworthy of the name "Swiss."
Swiss cheese hole size only counts if you care about aging. If the cheese has eyes, big or small, it's Swiss.