After doing so many things wrong the first time I attempted to make hard cheese, and then having it turn out as real cheese in spite of that, I just had to try it again. This time I used a gallon of whole milk, rather than skim.
Last night I poured a gallon of yesterday morning's milk into a big stainless steel pot and inoculated it with 1/4 cup of cultured buttermilk. This morning, I slowly heated it up to between 92 and 100 degrees, turning the burner off and on as needed. I stirred the curds and whey constantly with my VERY clean hand, and kept them at the required temperature for fifteen minutes.
We'll see if it turns out well this time. It'll be a month before I know.