Gjetost literally means “goat cheese” in Norwegian. The name is often applied in the United States to an unusual cheese made by evaporating down whey left over from making more traditional cheese. (I am told by a Norwegian fellow that the more correct name for this whey cheese is mysost. Here is his email to that effect, with a picture of gjetost.) What follows is a description of how to make mysost, apparently incorrectly termed gjetost in the States.
By reducing whey by simmering in an open pot, the salts, sugars and protein left in solution after separating the curds from the “curds and whey” are concentrated. This produces a cheese which is a combination of sweet, salty and caramel. You may want to try some gjetost from a local cheese specialty shop before you commit the time and energy to make it. It is a “cheese” unlike any other. It takes a long time to boil down the whey. (Not dissimilar to making maple syrup.)
1 gallon of fresh whey from making regular cheese
A stainless steel pot with a thick heat-dissipating bottom (either aluminum or copper). It should be larger than the amount of whey you will boil down (1.25 gallon capacity in this case)
A greased pan into which to pour the finished product.
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.