Pesto ( , Genoese ) is a sauce originating in Genoa in the Liguria region of northern Italy (pesto alla genovese). The name is the contracted past participle of pestâ ("to pound, to crush", from the same Latin root as the English word pestle), in reference to the sauce's crushed herbs and garlic.

History

The ancient Romans ate a cheese spread called moretum which may sometimes have been made with basil. The herb likely first came from North Africa, however it was first domesticated in India. On Food and Cooking: The Science and Lore of the Kitchen, First Scribner Revised Edition, Simon & Schuster, 2004. Basil took the firmest root, however, in the regions of Liguria, Italy and Provence, France. The Ligurians around Genoa took the dish and adapted it, using a combination of basil, crushed garlic, parsley, grated hard cheese (parmigiano-reggiano, pecorino, etc), and pine nuts with a little olive oil to form pesto. In French Provence the dish evolved into the modern pistou, a combination of basil, parsley, crushed garlic, and grated cheese (optional). However, pine nuts are not included.

In 1944, The New York Times mentioned an imported canned pesto paste. In 1946 Sunset Magazine published a pesto recipe, by Angelo Pellegrini. Pesto did not become popular in North America until the 1980s and 1990s.

Ingredients and preparation

Pesto alla genovese is made with Genovese basil, salt, garlic, Ligurian extra virgin olive oil (Taggiasco), European pine nuts (often toasted) and a grated hard cheese like Parmigiano Reggiano (but which may be Grana Padano, Pecorino Sardo or Pecorino Romano).

Historically, pesto is prepared in a marble mortar with a wooden pestle. The leaves are washed, dried, placed in the mortar with garlic and coarse salt, and crushed to a creamy consistency. The pine nuts are added and crushed together with the other ingredients. When the nuts are well-incorporated into the "cream", grated cheese or olive oil can be added and mixed with a wooden spoon. In a tight jar (or simply in an air-tight plastic container), pesto can last in the refrigerator up to a week, and can also be frozen for later use.

Commercial pesto is commonly available in supermarkets in either green (original) or red (with sun-dried tomatoes or red bell peppers) varieties, produced by major manufacturers or under a 'generic' or 'cheaper' brand. Cashew nuts or walnuts are often used instead of pine nuts, because they are less expensive and have a similar texture. Cheaper oils may also be used.

Pesto is commonly used on pasta, traditionally with Mandilli de Sæa (Genovese dialect - literally "silk handkerchiefs" - for lasagna), strozzapreti or trenette. It is sometimes used in minestrone. It is important never to cook pesto because basil gets bitter when heated.Fact: date=April 2009 Pesto is sometimes served on sliced beef, tomatoes and sliced boiled potatoes.