To prevent your pot from scorching, try "the cheese queen" Ricki Carroll
's technique of "icing" it: Put an ice cube in the pot and move the pot around so the ice covers every inch of the bottom as it melts. When the ice is entirely melted, leave the cold water in the pot and just add the ingredients to it. As long as you don't touch a metal spoon to the bottom of the pot as you stir throughout the recipe, the milk won't scorch the bottom of the pot.
Ice a large, heavy pot (see tip above). Add the milk and the lemon juice, and cream, if using, to the pot and stir without touching the bottom of the pot for 5 seconds.
Place the pot over low heat and attach a candy or cheese thermometer to the inside of the pot. Heat the milk mixture to 175°F. This should take 40 to 50 minutes, and you can stir once or twice over the course of this time.
Raise the heat to medium-high, and without stirring, watch the pot until the temperature reads 205°F, 3 to 5 minutes. The surface of the milk will look like it is about to erupt, but it shouldn’t boil. Remove the pot from the heat and let sit for 10 minutes. Now you have curds and whey.
Lay a fine-meshed sieve over a large bowl or jar and line it with a double layer of damp cheesecloth. Using a large slotted spoon, scoop the curds into the cheesecloth. Let the cheese drain for 10 minutes, and if you like, sprinkle salt over the top of the curds.
The ricotta can be stored, covered, in the refrigerator for 3 to 5 days.
Store in a covered container in refrigerator for up to 3 to 5 days. Do not freeze.
Reprinted from the book The Homemade Pantry by Alana Chernila. Copyright © 2012 by Alana Chernila. Published by Clarkson Potter, a division of Random House, Inc.