Have you ever wondered why cheese age for years but molds quickly in fridge?

There's a lot to talk about here:

  • All cheese molds, but of course when it's aging it's in very large blocks and only (for the most part) molds on the outside, where it can be discarded.
  • The rinds on cheeses that have them are a combination of drying and biological processes; so those do mold as well. In something like a brie the mold is actually the rind; on what's called a washed-rind cheese the rinds are (unsurprisingly) washed, so there's not much mold actively growing on them
  • you generally wrap cheese in your fridge in plastic, this holds moisture and creates a perfect environment for mold to grow. During aging cheeses will be allowed to breathe, so the rinds are drier and less susceptible to mold. If you buy an expensive cheese, it will be GREATLY improved by a couple of days wrapped in wax paper or another breathable wrapping, rather than plastic. Also - unrelated - let it warm to room temperature before you eat it!

Cheese is traditionally made in large blocks or wheels. These large chunks 'go bad' on the outside, protecting the inner cheese while it ripens. The outer rind is removed before it gets to you. The problem is that you've got a 2" thick slice of cheese that wants to form a 1" rind on both sides - there's nothing left in the middle.