Authentic pesto made in a mortar: a summer tradition amongst the olive groves of Dolcedo
The summer season on the Riviera di Ponente brings with it the intense fragrance of fresh basil, which grows in abundance in the terraced vegetable gardens of Val Prino. Making authentic pesto in a mortar is not simply a matter of following a recipe, but an ancient ritual that requires patience, precise movements and the careful selection of local ingredients. Discovering how to make this cold sauce according to Ligurian tradition allows you to bring the most authentic essence of our land to the table.
Summer basil from the Riviera: characteristics and selecting the leaves
The undisputed star of this dish is basil. During the warmer months, the plants benefit from prolonged exposure to the sun and the sea breeze that sweeps up the valley. To achieve the perfect pesto, the choice of raw ingredients is crucial. Not all basil plants are suitable: large, thick leaves with a strongly minty scent – typical of certain varieties grown in greenhouses or in different climates – would upset the balance of the sauce.
Tradition calls for small, tender, oval-shaped leaves of a pale green colour. These leaves contain an ideal concentration of sweet essential oils, without that hint of menthol which risks overpowering the other ingredients. The best time to harvest is in the morning, when the plant is well-hydrated and the leaves are plump. Before use, the basil must be washed very gently in cold water and dried thoroughly on a clean tea towel, patting gently without pressing, to avoid breaking the scent-bearing vesicles prematurely.
Val Prino extra virgin olive oil and other local ingredients
If basil is the soul of pesto, extra virgin olive oil is its body. In the hills around Dolcedo, the cultivation of the Taggiasca olive defines both the landscape and the table. The oil produced in this area of the Imperia hinterland is renowned for its delicacy. Unlike the more full-bodied and pungent extra virgin olive oils of southern Italy, oil made from Taggiasca olives is lightly fruity, with a tendency towards sweetness, and a characteristic hint of almond. This subtle nature makes it the perfect binding agent for pesto: it envelops the ingredients and brings out their flavours without overpowering the freshness of the basil.
As well as the oil and basil, the traditional recipe calls for ingredients of the very highest quality:
- Garlic: preference is given to garlic grown in the inland areas of western Liguria, known for its delicate aroma and ease of digestion. Only a moderate amount is used in the pesto so as not to overwhelm the palate.
- Pine nuts: these must be Italian-grown, of the highest quality, and capable of giving the sauce a buttery texture and a sweet flavour.
- Cheeses: a blend of Parmigiano Reggiano PDO (aged for at least 24 months) and Pecorino Sardo PDO (preferably ‘Fiore Sardo’) is used. The former adds sweetness and body, whilst the latter imparts a savoury and slightly piquant note.
- Coarse salt: strictly sea salt and coarse-grained. As well as adding salt, the salt crystals perform a vital mechanical function whilst being ground in the mortar.
The mortar technique: why metal is the enemy of basil
Making pesto with an electric blender is a common temptation, but the result will never compare to that achieved with a mortar. The metal blades of modern appliances spin at extremely high speeds, generating heat through friction. This sudden rise in temperature causes the basil to oxidise immediately: the leaves turn black and the essential oils evaporate, leaving behind an unpleasant bitter and grassy flavour. Furthermore, the blades cut through the leaf fibres rather than crushing them.
The marble mortar with a boxwood or olive wood pestle, on the other hand, works ‘cold’. The correct technique does not involve pounding the ingredients forcefully, but rather crushing and rotating them against the curved sides of the marble. This process of rubbing and pressure gently breaks down the cell membranes of the leaves, gradually releasing the essential oils and blending them with the extra virgin olive oil and cheeses. The result is a thick, creamy emulsion with a bright green colour and a lingering aroma.
The step-by-step preparation ritual
The preparation of pesto in a mortar follows a precise sequence, established by generations of Ligurian cooks. Each ingredient must be added to the mortar at the right moment to ensure the perfect consistency.
Start by peeling the garlic clove, removing the inner core if you want an even more delicate flavour. The garlic is placed in the mortar along with a pinch of coarse salt and the pine nuts. Using the pestle, begin to work the mixture with a circular motion, pressing against the sides until it is reduced to a smooth, white paste.
At this point, add the basil leaves – ensuring they are thoroughly dry – along with a little more coarse salt. The salt acts as a natural abrasive at this stage, helping to crush the leaves without tearing them. The pestle should be moved in a constant circular motion, starting from the centre and working outwards along the edges of the mortar. You will immediately notice a bright green liquid being released.
Once the basil has been reduced to a fine paste, it is time to add the grated cheeses. Add the Parmigiano Reggiano and Pecorino Sardo, continuing to stir with the pestle to blend the powders into the moist base. Only at the very end should you slowly drizzle in the Val Prino extra virgin olive oil. The oil must not be pounded, but gently incorporated using circular movements of the pestle or a wooden spoon, until you achieve a smooth, perfectly emulsified sauce.
Traditional Ligurian summer pairings
Pesto is a versatile sauce that finds its finest expression on the Ligurian table in summer. As well as the classic pairing with fresh trofie or trenette – cooked strictly with fresh green beans and diced potatoes – pesto lends itself to various interpretations typical of the warmer months.
An excellent example is Minestrone Genovese. During the summer months, this hearty dish made with garden vegetables, fresh beans and trombetta courgettes is served lukewarm or even at room temperature. Before serving, adding a generous spoonful of fresh pesto, made in a mortar, transforms the vegetable stock, enriching it with aroma and creaminess.
Another interesting summer pairing involves cold dishes such as Cundigiun (the Ligurian ‘condiglione’), the quintessential summer salad made with beefsteak tomatoes, peppers, cucumbers, red onion and Taggiasca olives. Although the classic recipe calls for only oil, vinegar and salt, many people like to serve this salad with croutons of homemade bread, lightly rubbed with garlic and drizzled with a thin layer of fresh pesto, thus combining the freshness of the raw vegetables with the intense aroma of basil.
Davide’s Tip: On hot summer days in Val Prino, if you’re picking basil straight from the vegetable patch, do so early in the morning before the sun heats the leaves and causes the essential oils to dissipate. Before you start pounding, place the marble mortar and pestle in the fridge for about half an hour: the cold will prevent the heat generated by the pounding from oxidising the basil leaves, keeping your pesto a bright, vibrant green.
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