Conserva di pomodoro (tomato preserving) is the great annual ritual of southern Italian food culture—the late-summer practice of processing hundreds of kilograms of ripe San Marzano or Roma tomatoes into passata (puréed and strained), pelati (whole peeled), and conserva (concentrated paste) that will supply the family's pasta sauces, soups, and braises for the entire year. In Campania, Puglia, Calabria, and Sicily, the conserva is not merely food preservation—it's a family event (la raccolta) that brings together multiple generations over one or two intense August days of washing, blanching, peeling, puréeing, bottling, and processing. The most common product is passata—tomatoes blanched, peeled, seeded (or not), puréed through a food mill (passapomodoro), bottled in sterilised glass bottles with a basil leaf, sealed, and boiled in a water bath for 30-40 minutes to ensure shelf stability. The whole operation—from crates of ripe tomatoes to rows of sealed, ruby-red bottles cooling on the kitchen floor—takes place outdoors or in a garage, with enormous pots on gas burners, trestle tables piled with tomatoes, and family members at every station. The quality of the tomatoes is paramount: they must be ripe (but not overripe), firm, and flavourful—San Marzano DOP from Campania remains the benchmark. Estratto di pomodoro (concentrato/sun-dried tomato paste) is the most concentrated form: tomato purée spread on wooden boards and dried in the sun for several days, stirred regularly, until it reduces to a thick, dark, intensely flavoured paste—a practice that survives in Sicily and southern Calabria.
Late-summer preservation of ripe tomatoes (August/September). Passata: puréed, bottled, water-bath processed. Pelati: whole peeled in their juice. Estratto: sun-concentrated paste. A family and community ritual. Sterile processing is essential for safety. Quality tomatoes are non-negotiable.
The tomatoes should be at the peak of ripeness—sweet, red, and slightly soft but not mushy. A manual passapomodoro (food mill) removes skins and seeds more efficiently than any blender. Add one fresh basil leaf per bottle before sealing. Check every bottle after 24 hours—if any lid is not concave (vacuum-sealed), refrigerate and use immediately. Bottles should be stored in a cool, dark place and last 12-18 months.
Using unripe or poor-quality tomatoes (the preserved product can't be better than the raw ingredient). Insufficient water-bath processing (botulism risk—process for at least 30-40 minutes). Not sterilising bottles properly. Adding too much basil or other aromatics (they can ferment). Storing in direct light (degrades colour and flavour).
Arthur Schwartz, Naples at Table; Touring Club Italiano, Regional Italian Cooking