The San Marzano tomato variety has few seeds and little pulp, making it an excellent tomato for making pastes and sauces. San Marzano tomatoes also freeze well, for the same reasons. Cooking the tomatoes and freezing them provides a long-lasting supply for use in soups, casseroles, baked tomato dishes, or for future paste- or sauce-making. Use only San Marzano tomatoes of the best quality, with firm flesh and no visible bruising, for freezing.
Bring 1 gallon of water to a full boil in a large pot. Submerge the whole San Marzano tomatoes in the water and bring it back to a boil. Boil the tomatoes for about one minute, or until the skins begin to split, then transfer them to a bowl of ice water to cool.
Peel the spit skins from the tomatoes. Cut out the stem core with a paring knife then cut each tomato into quarters.
Place the sliced tomatoes in a pot. Heat over medium high heat until the tomatoes begin to simmer, stirring frequently. Cook the San Marzano tomatoes for 15 to 20 minutes, or until they are tender.
Fill the sink with ice. Set the pot in on top of the ice so the tomatoes cool quickly to room temperature.
Transfer the cooked tomatoes to a freezer-safe storage bag or container, leaving 1 1/2 inch of head space at the top of the container so the tomatoes can expand during freezing. Push the air out of the bag, if you're using bags. Seal the container or bag and store it in a 0-degree Fahrenheit freezer for up to one year.
If you prefer whole, unstewed tomatoes, freeze them immediately after blanching and peeling.