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.
Equipment
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)
Protocol
Whey left from turning five gallons of milk into cheese will make about 1.5 – 2 pounds of ricotta (a quart or so)
1) Save the whey from making cheese in a non-reactive pot. (Here you see curds for a basic cheese at the bottom of the pot, as the whey is being poured off). Filter as much of the curd particles out as you can since they would otherwise form tough “beads” in the final ricotta. Cover and let sit 12 to 24 hours at room temperature to develop sufficient acidity.
2) The next morning, heat the acidified whey with stirring taking care to avoid sticking or burning. Use either a double boiler, or a pot with very thick bottom which will disperse the heat well. This image shows that the temperature has risen to about 82 °C, and a white foam is appearing on the surface.
3) Continue heating with stirring until its temperature is near boiling (95 °C). Note that foam will build up somewhat. (Careful: if it boils, it can boil over…) Remove from heat. Cover and allow the “cooked” whey to cool undisturbed until comfortable to the touch. The curds should look like clouds suspended in the whey, while the whey appears clear and yellowish green. (Riboflavin in the whey gives it this color.)
4) DO NOT STIR UP THE CURD: Set up a receiving pot with a large strainer and a fine clean cloth on top. If the curd is floating, you may dip out the curd into the cloth. Alternatively, if the curd all sinks, pour as much of the whey through the cloth as you can without disturbing the curds. It will filter through MUCH faster if you do this carefully without sitrring up the curds.
5) Gently scoop out the curds. Because the curds are very fine and delicate, they can stop up the cloth easily. This will cause very slow draining if they are broken up.
6) You can see that much of the whey will drain out as you dip the curd.
7) After all of the wet curds have been transferred to the cloth, allow the whey to drain out through the cloth (be patient, it can take 2-3 hours). Then pick up the corners of the cloth, suspend like a bag over the drainage pot (or sink) to allow the last of the whey to drain out. It will take several hours, and can be done in the refrigerator over night. The whey remaining from ricotta is clear, and has a greenish-yellow tint from the riboflavin which remains. This whey has very little protein remaining in it, and I feed it to my chickens and my pig.
8) Remove the ricotta from the cloth, pack into a container, cover and store in the refrigerator. Use it soon after making. Alternatively, ricotta will freeze very well.
Related:
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.
David Fankhauser 