If you have eaten Greek yoghurt before (particularly the Fage brand), you would have noticed a round of parchment after you peel off the foil lid. The presence of the parchment is to absorb extra whey that usually comes to the top after sitting undisturbed for some time. Keeping in mind that the whey will separate out with time, it means you can easily make Greek yoghurt by yourself if it is not readily available. Just pour a regular cup of plain yoghurt onto a cheese cloth, tie it up and let hang in your fridge. The whey will separate out from the yoghurt, and you will end up with a much thicker yoghurt than you started. That’s Greek yoghurt. It is also why Greek yoghurt costs more than regular yoghurt, as it has more solids by weight.