San Marzano tomatoes are the gold standard of canned tomatoes, heavily marketed all over the world. Recipes call for them by name, chefs pay exorbitant prices for their favourite brands and Italian authorities thunder grandiloquent threats against those who sell lesser tomatoes under this famous name. Chefs and home cooks alike will use San Marzanos when they are available, but sometimes a substitution is necessary.
About San Marzano Tomatoes
San Marzano is a town, a growing region, a tomato cultivar and a recognised EU agricultural designation that encompasses all three of those aspects. The only canned tomatoes legally entitled to be sold as San Marzanos are those of the original cultivar, from the original growing region around the village of San Marzano in Campania. Legitimate San Marzano tomatoes carry the acronym DOP on their labelling, from the Italian phrase "Denominazione d'Origine Protetta."
San Marzano-Type Tomatoes
Aside from its status as a protected designation under EU and international law, the San Marzano tomato is a plum-type cultivar that can be grown anywhere other tomatoes flourish. The San Marzano is longer and thinner than most plum tomatoes, with thick and meaty flesh and relatively little juice or seeds. This makes San Marzanos excellent for canning or sauces. San Marzanos grown and canned elsewhere make a usable substitute for the legitimate article.
Other Canned Tomatoes
When true San Marzanos and other San Marzano-type tomatoes are unavailable, other canned plum tomatoes can be used in their place. Their flavour is not as fine as those of the San Marzano, but the texture will be similar once the tomatoes are drained. The individual cook or chef will need to taste the sauce frequently, and adjust the seasonings to compensate for the loss of the signature taste of the San Marzanos.
Fresh San Marzanos
At times, when canned San Marzanos or other tomatoes are not available, it may be possible to secure fresh San Marzano tomatoes from a local grower. To substitute fresh San Marzano tomatoes for canned tomatoes, blanch them for a minute or two in boiling water to loosen the skins. Drop the tomatoes into ice water to prevent them cooking any further, and peel off the skins. Halve the tomatoes and squeeze out the juice and seeds, then cook the tomatoes down and make sauce according to your favourite recipe.