The cult of San Marzano

It’s late August at Trullo in Islington, London, and I’m tucking into a plate of Dorset lamb rump and bobby beans, bolstered by the intense umami of Olasagasti anchovy, and the unique properties of San Marzano tomato. The “tomatoes are cooked down to draw out their natural sweetness and gentle acidity,” says Ed Grace, head chef, which helps to cut through the saltiness of the anchovies, and the earthy, bitter undertones of the bobby beans. “Likewise, given their intense sweetness, low acidity and rich umami, they are an unbelievably versatile product and so align very easily into simple summer cooking.” 

Few ingredients in Italian cooking command such reverence. Long, elegantly-shaped, and grown in the shadow of Mount Vesuvius, San Marzano tomatoes are an example of where terroir is taken as seriously as in the world of wine nerdery. Grown in the territory of Southern Campania, they are a product of mineral-rich volcanic soils, Mediterranean sunshine, and generations of cultivation. They have become the gold standard for sauces—sweet, low in acidity, and packed with an intensity that elevates even the simplest plate of pasta.

The tomato’s reputation is such that it has inspired iconic dishes, from rustic trattoria plates and Neopolitan pizza (it’s the classic choice for pizza sauces across Italy) to fine dining. At one point, the three-Michelin-starred chef Niko Romito built a version of spaghetti al pomodoro around them, showing that even Italy’s most ambitious kitchens recognised the San Marzano as an ingredient worthy of the spotlight.

The secret of San Marzano lies beneath the surface. The eruption of Vesuvius covered southern Campania with layers of lava and ash, creating soils dense with minerals but free-draining enough to prevent disease. “The area around South Naples, covered by lava and ash from Vesuvius, is incredibly rich in minerals and organic elements,” explains Roberto Rossi, a fifth-generation trader who once ran Natoora’s Italian buying operations. 

For him, terroir is everything. “Would you be happy to pay €50 for a bottle of Brunello grown in Friuli? Or in Basilicata? That’s why I’m not in love with hydroponic cultivation.”

That sense of place is protected by DOP (Denominazione d’Origine Protetta) status. The variety most associated with San Marzano, SMEC 20, was rediscovered through a blind tasting of historic seeds in Salerno, a port city southeast of Naples, with the aim of ensuring authenticity in both plant and provenance. The DOP rules specify not just the seed but the exact growing area—a patch of land in the Agro Sarnese-Nocerino plain near Naples—which explains how San Marzano became a tomato rooted as much in inter-generational tradition as it is in flavour. 

San Marzano’s reputation has also made it a target for disputes over authenticity. In recent years, lawsuits in the U.S. challenged brands claiming to sell ‘Certified San Marzano’ tomatoes that were not grown in the designated Campania region, highlighting the high stakes of provenance in a global market.

While provenance is critical, chefs value San Marzano for how they behave in the pan. For Grace, it’s as much about their structure as much as their taste. Unlike many tomatoes, San Marzano have a high flesh-to-water ratio, which means they cook down quickly, yielding sauces that are rich but never muddy. “Beyond their immediate distinct mineral quality,” Grace says, “San Marzano stand out from alternative tomatoes given their meaty texture and lower water content and high flesh content. As a result, these characteristics result in a sauce that’s not only rich and naturally balanced but retains a degree of freshness as the cooking time is less.” 

But what happens when San Marzano are grown outside Campania? In recent years, growers on the Isle of Wight have cultivated their own versions. “Whilst there’s no denying that a Isle of Wight San Marzano eaten at the absolute height of summer is enjoyable,” Grace says, “UK soils—though fertile—lack that specific volcanic composition, and so the tomatoes don’t have the same depth of flavour.”

Rossi, who has spent decades tasting tomatoes across Italy, agrees that every variety has its natural context. The thick-skinned Piennolo, for example, excels only when cooked; the tiny Datterino depends on Sicily’s saline soils to develop its sweetness; and the Sorrentino surpasses San Marzano in a raw Caprese. “One thing I love about tomatoes is that they are so different in taste that for every dish you want to prepare, you will find the perfect one,” he says. San Marzano’s uniqueness, then, isn’t that they are better than all others—but that their volcanic terroir gives them a balance and depth chefs find hard to replicate elsewhere.

Yet flavour alone doesn’t explain the enduring power of San Marzano. Their reputation is also tied to the story of where they come from. The image of a tomato ripening in sight of Vesuvius has become almost mythic. “There’s no denying that the picture of the San Marzano tomatoes growing at the base of Mount Vesuvius is a very evocative image,” Grace says, “and therefore underpins people’s perception of its flavour.” 

That duality of story and substance explains why tinned San Marzano commands such loyalty among chefs and home cooks alike. “Guests and home cooks are becoming increasingly aware of the vast flavour difference compared to different canned tomatoes,” Grace explains. For him, cooking with them in London is a way of importing a little of that terroir into a different seasonal context. For home cooks and diners alike, tinned San Marzano can have transportative effects—brightening evenings in the biting cold of deep winter.