Hi Margarita
If the Greek yoghurt you are using has at least 10g of protein per 100g, it would mean that the yoghurt has already been strained to increase the protein density.
Here in the UK, my mother (for preventative measures) has, for the last 12 years, used "Fage" Greek yoghurt for her focc.
The ingredients are the same as Quark, but Quark typically has 12g of protein per 100g.
Kind regards
Julie
