The canned San Marzano tomato is better than most fresh supermarket varieties. If these are not readily available near where you live, you can buy canned San Marzano tomatoes online at Amazon.com although they are not cheap. The Italians claim that it’s not just the tomato but where it’s grown (volcanic soil) that contribute the high character in this tomato. You may grow your own; vines start bearing later in the summer. There is little doubt in this author’s mind that these tomatoes make a superior sauce if you do not have home grown or farm fresh ripe tomatoes.
Common Brands include Cento, Colucchio, Lavalle, and Strianese. Avoid cans without the DOP marking.