'recooked' or 'refined') protein can be harvested if the whey is first allowed to become more acidic by additional fermentation (by letting it sit for 12–24 hours at room temperature).

The combination of low pH and high temperature denatures the protein and causes it to flocculate, forming a fine curd.

In the second millennium BC, ceramic vessels called milk boilers started to appear frequently and were apparently unique to the peninsula.

[4] The increased production of rennet-coagulated cheese led to a large supply of sweet whey as a byproduct.

[3] The ancient Romans made ricotta, but writers on agriculture, such as Cato the Elder, Marcus Terentius Varro, and Columella, do not mention it.

[8] Fresh ricotta can be subject to extra processing to produce variants which have a much longer shelf life.

These are allowed to age for about a year, during which salt is added and the cheese mixed every two or three days to prevent the growth of mold.

Ricotta can be beaten smooth and mixed with condiments, such as sugar, cinnamon, orange flower water, strawberries, and occasionally chocolate shavings, and served as a dessert.

This basic combination (often with additions such as citrus and pistachios) also features prominently as the filling of the Sicilian cannoli and layered with slices of cake in Palermo's cassata.

Combined with eggs and cooked grains, then baked firm, ricotta is also a main ingredient in Neapolitan pastiera, one of Italy's many "Easter pies".

[12] Ricotta is also commonly used in savory dishes, including pasta, calzone, stromboli, pizza, manicotti, lasagne, and ravioli.

It also is used as a mayonnaise substitute in traditional egg or tuna salad[citation needed] and as a sauce thickener.

While both types are low in fat and sodium, the Italian version is naturally sweet, while the American is a little saltier and moister.

The name and technique of preparation change according to the region where it is produced: it is called Greuil,[14] Breuil[15] or Sérou in Gascony, Zenbera in the Basque country, Brousse in Provence, Brocciu in Corsica and Sérac in the Alps.

It is sometimes used as filling for tlacoyos and tacos dorados, and in the central west area (Jalisco, Michoacán, and Colima) it is spread over tostadas or bolillos, or served as a side to beans.

[21] In Greece, cheeses very similar to ricotta are anthotyros (ανθότυρο) and manouri (μανούρι), made from sheep or goat milk.