Pour milk into a sterilized pot. Place pot into a larger pot filled with a few inches of water. Heat milk, stirring occasionally, to 90 degrees F (32 degrees C). Remove from heat.

Dissolve calcium chloride in 1/4 cup water; stir into the milk. Sprinkle mesophilic culture over the surface of the milk. Let sit for 1 minute, then stir gently for 1 minute. Cover and let culture ripen for 35 minutes.

Dilute rennet with 1/4 cup water. Stir rennet into the milk mixture for exactly 1 minute. Cover again and let sit until a knife can cut cleanly through the curd, about 45 minutes. Cut curd into 1/2- to 1-inch cubes directly in the pot. Let sit for 5 minutes.

Cover curds and heat, stirring every 10 minutes, to 98 degrees F (37 degrees C), about 90 minutes. Squeeze curds together to check if they stick. Drain curds and transfer to a cheesecloth-lined strainer set inside a pot.

Pour enough whey over the curds to reach about 3 inches at the bottom of the pot. Let drain for about 1 minute. Cover with cheesecloth and the pot lid. Heat the whey below to keep curds between 112 and 115 degrees F (44 and 46 degrees C); let drain for 10 minutes. Curds will stick together to form a slab. Cut slab in half, re-cover, and let drain for 10 minutes.

Flip curds over and re-wrap. Drain for 10 minutes more, keeping the temperature still between 112 and 115 degrees F (44 and 46 degrees C). Cut the slab into smaller slabs and stack them inside the cloth. Return to the pot and cover. Continue draining, flipping and rearranging the slabs every 15 minutes at the same steady temperature, about 1 hour total.

Unwrap the slabs and let them rest for a few minutes on a paper towel-lined plate. Cut into cubes and place curds in a zip-top bag. Add 1/2 of the salt; shake to coat. Add remaining salt and repeat.