San Marzano tomatoes are a deluxe variety native to Southern Italy. Since conquering the world and spreading their fame far beyond Italy, these tomatoes have become synonymous with thoughtful, gourmet cooking. They have proven so popular that the most widely-distributed plum tomato — the Roma — is actually a descendant of this aristocratic variety.

However, most food lovers are familiar with the canned preserved version, which allows devotees of Italian food the world over to appreciate these flavorful, sun-drenched specialties. The name found on the can refers to both the type of tomato, as well as the region in Italy where they are — by law — required to be produced. However, there is more than meets the eye here, and navigating the labels of various products that bill themselves as authentic San Marzanos can be intentionally complicated.