For a really good tomato sauce, you should use the best: San Marzano tomatoes.
These distinctive plum tomatoes are the most celebrated of the many kinds of canned tomatoes imported from Italy. Fortunately, they are available in the United States at most supermarkets. If you can’t find them, try the internet or an Italian deli.
San Marzano is a town outside of Naples and the center of the growing region where a particular variety of tomato got its reputation. The volcanic soil of the area is extremely fertile, and the intense sun of Campagna reflects off the metallic particles in the volcanic soil, bathing the tomatoes in sunshine from all sides. This makes them wonderfully sweet. The only canned tomatoes that can be labeled as “San Marzano” must have been grown in the designated district. And only the finest of these can carry the DOP seal, guaranteeing that they have been produced to the standards of the San Marzano growers’ consortium.
I encourage you to use San Marzano that are truly grown in Italy. Read the labels of cans carefully. Many brands will process tomatoes from other countries but proclaim they are “Packed in Italy”. Others are just “Italian-Style”, which likely means they have some basil in the can. “Italian style” on the label indicates a style of preparation, not the country of origin. “Grown and packed in Italy” on the label will ensure you an authentic Italian product. For best results, look for San Marzano Pomodori Pelati (peeled tomatoes from San Marzano) on the label when buying imported canned peeled tomatoes.