Why when cheese is kept wrapped in celophane, do moisture droplets form on the cheese surface? I’ve found that this only occurs after the cheese has been opened from its original vacuum- packed wrapping. The sweat occurs even when stored securely in a zip-loc bag. Can anyone shed some light on this phenomenon? Thanks.
The cheese isn’t sweating, the air is. When you close the Zip-Loc bag, you seal in a quantity of warm, moisture-laden air; the moisture then condenses when you put the bag in the refrigerator. Cheese being relatively hydrophobic, the water beads on the surface instead of soaking in.
I seem to find this water bubbling only happens with cheese though and so quickly. Are there any particular ingredients of cheese that cause this more so than other foods? For instance, butter is also hydrophobic, but I don’t see this phenomenon occuring with it nearly as much if at all.
Well, you might also be seeing oil coming from the cheese, but that’s usually only at room temperature. Are you saying that you keep your butter in a plastic bag?
Yeah, I keep my butter stick in a zip-loc. Is that strange? 
Um, kinda. However, I have nonetheless seen butter develop a film of moisture on its surface (usually when it’s removed from the fridge, though), due to moisture condensng on the cold surface of the butter.
Cheese does contain some water, but it’s hard for me to imagine it coming out on its own. Usually water (or oil) only comes out of warm cheese.