One of my host families kept glasses of some sort of thick mixture (I never saw how it got there) which they would put in a blender to froth up. They called it something like culhado, but I haven’t gotten anywhere googling variations on that word. The other families I lived with would have avocado and/or banana smoothie-type drinks, but this had more of a tart, unsweetened yogurt flavor along with something I vaguely thought might be orange juice. I never had it anywhere but at that one house. This would have been in the state of Sao Paulo in the early 80’s.
Could it be coalhada? (See the Wikipedia article in Portuguese). I’ve never eaten it, but my my limited comprehension of Portuguese suggests it’s a name for fermented curds. Something like Icelandic skyr I’m guessing.
I love this board.