It's a pretty straightforward answer: the parchment round absorbs any excess whey that rises to the top after the yogurt is packed. Whey — that clear liquid that often separates out from yogurt a day or two after it is opened — is also what is strained away from Greek yogurt to make it thicker than regular yogurt. Even after that, enough remains to be soaked up by that little circle of paper.
So there you have it — a little daily mystery solved!
• Read more: What Is The Paper Thing In My Greek Yogurt? at Food Republic
(Image: Anjali Prasertong)