Look for milk that is heavy in cream/fat content. Back home in Europe I buy a German milk called berchtesgadener milch, which works very well. In California, I buy Rosa Brothers, Straus, or Broguiere - anything that comes in a fancy glass bottle works better than a carton, in my experience, for this recipe.
Take a heavy-bottomed saucepan, pour in the milk, and heat it on a medium flame to around 175°F on a kitchen thermometer.
1 quart fresh whole milk
Without turning off the heat, add the vinegar and continue stirring for a minute, but do not bring the milk to a boil. A gentle simmer is enough.
2 tablespoons of apple cider vinegar
When some small lumps begin to form, cover the pot with a clean dry cloth and let it cool down.
When the contents of the saucepan will return to room temperature, collect the cheese curds with a skimmer and put them to drain in a colander covered with sterile gauze, like you would when making labna cheese. Collect the remaining liquid in the saucepan, as well as all the liquid that drains from the cheese curds, and set it aside to make ricotta.
Transfer the colander to the fridge and drain the cheese overnight.