Ricotta is Italian for “recooked” because it is made by “cooking” whey which is produced when the curds are separated for cheese (“curds and whey,” as in little Miss Muffet). The chemistry of ricotta is interesting. Its production relies on allowing the inoculated bacteria in whey to further ferment the liquid as it sits at room temperature for an additional 12-24 hours. During that time, the remaining sugars are converted to lactic acid which lowers the pH of the whey. The solubility of the protein in acidified whey is reduced. Heating the acidified whey denatures the protein causing it to precipitate out as a fine curd. This small-grained curd may be then dipped out or filtered out by pouring through a fine cloth. It can be used fresh or frozen until needed.
1) Non-reactive pot, either stainless steel or enameled (I have a wonderful 5 gallon stainless steel pot with a thick aluminum pad bonded to the bottom to disperse the heat. It is made by Vollrath, and was, I recall, somewhat expensive ($50-60 ten or fifteen years ago). If you use a thin enameled pot, you should either heat the whey in it over boiling water, or stir nearly continuously.
2) Wooden spoon or long handled spatula (with square end to help to keep curd off the bottom)
3) Thermometer (0-110 °C) to monitor temperature of whey while heating
4) Receiving pot the same volume or greater as cooking pot (a clean plastic bucket will do)
5) A fine meshed strainer to dip out floating curd.
6) Large strainer to suspend over receiving pot
7) Fine cloth (I use a clean sterile handkerchief or a non-terry cloth dish towel)
Whey left from turning five gallons of milk into cheese will make about 1.5 – 2 pounds of ricotta (a quart or so)
Ricotta cheese makes delicious lasagna, ravioli stuffing, gnocchi, (“Italian dumplings”) and the famous Italian dessert, cannoli, cheese-stuffed shells and blintzes, or a type of cheese cake.