Zero, an extra-virgin olive oil from the century-old olive groves of Tenuta Marmorelle in Puglia, is so-called because it has an acidity of just 0.2 per cent. The olives are hand picked and cold extracted on the same day and the oil is hand bottled unfiltered. A winner of two stars in the 2014 Great Taste Awards, it has a delicious, fresh-herb and spice pungency and costs £14.95 for 500ml from Puglia Shop Online.