While both parmigiano reggiano (aka parmesan) and pecorino romano are hard, salty, Italian cheeses that are often served grated, they're not the same nor 100 percent interchangeable. Here's what you need to know:
- Production: Parmigiano reggiano is made from cow's milk and is aged a minimum of 12 months (two- and even three-year versions are available at some cheese shops). Pecorino Romano is made from sheep's milk and is aged a minimum of five months (and up to eight).
- Region: True parmigiano reggiano and pecorino romano are DOP-designated foods, meaning they are produced in a specific region of Italy according to set standards. (This ensures a consistent product.) Parmigiano reggiano can only be produced in the Emilia-Romagna region (which includes Parma, hence its name), and the Mantova province of Lombardy. Pecorino romano can only be produced in the regions of Tuscany, Sardinia (where much of the production occurs), and Lazio.
- Appearance: Parmigiano reggiano is hard and golden in color, with a waxy rind stamped with "Parmigiano Reggiano" in dot lettering. Pecorino romano is hard and white (as sheep's milk cheeses tend to be), with a waxy mottled black rind.
- Flavor: While both are salty and umami-rich, pecorino romano is saltier and tangy, whereas parmigiano reggiano is nutty and a bit milder overall. While similar in flavor, they're not interchangeable — some recipes call for a mix of the two, whereas others only call for one. We tend to heed these recommendations, but you do you.