Pesto from the mortar — pestare means to pound in Italian — produces a sauce of different character from blender pesto. The mortar's compression ruptures basil cells without shearing them; the cell walls collapse slowly, releasing the basil's volatile aromatic compounds into the olive oil rather than oxidising them on the blade's hot surface. Blender pesto tastes competent; mortar pesto tastes of summer in Liguria.
- **The basil:** Small-leafed Ligurian basil (Ocimum basilicum 'Genovese') — more delicate and less anise-forward than large-leafed Italian basil. Cold water-washed and completely dry before pounding. Any residual water in the basil dilutes the olive oil emulsion - **The sequence:** Garlic + coarse salt (as abrasive) first → pine nuts → basil (in batches) → Pecorino Sardo + Parmigiano → olive oil - **The salt as abrasive:** Added with the garlic at the start — the salt crystals help grind the garlic and basil against the mortar surface rather than bruising it - **The oil:** Added last, slowly, worked into the paste - **The temperature:** Pesto loses its colour rapidly at temperature — prepare at room temperature, serve at room temperature, store with a layer of olive oil on top. Never heat pesto directly (it blackens and turns bitter). Toss with pasta off heat or in very low heat **Why blender pesto is inferior:** - The blender blade's friction generates heat — temperatures briefly exceed 50°C at the blade surface, driving off the most volatile aromatic compounds - The shearing cuts the basil cells open uniformly — this allows rapid oxidation of the chlorophyll and produces the grey-brown colour within minutes Decisive moment: The garlic reduction — the moment the garlic and salt have been worked to a completely smooth paste with no identifiable garlic pieces. All subsequent ingredients build on this base; incompletely ground garlic produces a pesto with harsh, sharp garlic notes rather than the integrated, slightly sweet garlic character correct pesto requires.
Hazan