Pour the dairy, lemon juice, and salt in a sous-vide bag, agitate the bag a bit, and place the bag in a 195-degree water bath. Let it cook for one hour, until you see a bunch of curds form. Remove the bag from the bath, and let everything cool until you can handle it comfortably.
Carefully pour the now-curdled milk into a colander lined with a couple of layers of cheese cloth, let it drain for an hour or more, depending on dry you like your ricotta to be. Transfer to some sort of seal-able container and refrigerate.
