Acid-set queso fresco

Add the buttermilk to the gallon of milk in a heavy pot.

Variation: let the slightly warmed milk and buttermilk sit 4 to 24 hours for a more complex cultured flavor.

Heat slowly, stirring so it does not scorch, to about 190 degrees -- steaming at 160, just before a bare simmer at 190; about 20 minutes. If it reaches a gentle simmer, turn it off and let it cool 10 to 15 minutes.

Turn off the heat, add the lime juice and stir very slowly and gently; curds form at once.

Let sit about 10 minutes for the curd to firm.

Dampen cheesecloth and lay it into a strainer.

Ladle the curds out of the whey with a skimmer into the cheesecloth.

Gather the cloth, twist lightly and press out whey: less for a ricotta-like texture, more for crumbly queso fresco.

Open the cloth, sprinkle the teaspoon of salt over and work it in with a spoon.

Gather into a disc or a ball tied at the top with string.

Refrigerate overnight, or as little as two hours; texture is better the next day.

Crumble into tiny bits rather than smearing.