Basil basics

Pesto science in the kitchen

Tiare Dunlap
April 21, 2011

Caprese, pizza margherita and pesto: where would Italian food be without basil? It is the garnish that guarantees the provenance of your plate. But there is a great deal of science behind Italy's centuries-old art of cooking. Tiare Dunlap tells us about the molecular motives behind Liguria's traditional pesto.


The time and care Italians put into crafting their food is often viewed as symptomatic of their devotion to a distinctively elevated quality of life. No matter what situation, quality always comes before expediency (or so I tell myself whenever waiting more than an hour for something that should take 10 minutes). Italians do things at their own pace, and if you are going to spend any amount of time here, this is something you must accept. However, when it comes to their world-famous cuisine, Italians take their sweet time not because of their culture, but because the molecular composition of their ultra-fresh ingredients demands it.


For example, any John or Jane could whip up some pesto at home with basil, olive oil, pine nuts, pecorino cheese, and salt. It's a great recipe to impress those who are less kitchen literate than you and lets you feel you are being healthy (green = good for you and the earth). However, when you leave the comfort of your home and food processor for the greener culinary pastures of Italy's Ligurian coast, you will see that the flavor you produce at home does not even live in the same neighborhood as the party an authentic pesto will no doubt throw on your taste buds. The difference isn't in the siesta, it's in the science.


Pesto was created by accident when an ancient Ligurian used olive oil to preserve the basil leaves that abound on his region's coastline. To have such an incredible feat of gastronomy result simply from the effort to store an abundant herb makes me wonder what culinary triumphs we are missing by having refrigerators.


The name pesto comes from the history of grinding the fresh ingredients into a silky green sauce using a mortar and pestle. In today's fast-paced world where the minutes spent grinding pesto with a stone apparatus would seem better spent tweeting, most people gladly opt for a blender or food processor. Although electing to grind herbs together using a mortar and pestle may feel like lighting a fire with two sticks while you have a lighter in your pocket, the choice of mixing apparatus influences both flavor and consistency.


First off, grinding roasted pine nuts and coarse salt into a velvety mixture will provide a creamy foundation to showcase your basil's flavor. Each basil leaf contains thousands of microscopic glands filled with flavorful essential oils that cover the surface of the herb. So-called young leaves harvested from the top of the plant generally have a larger proportion (as much as five times more) of the aroma compounds than the more mature leaves found at the plant's base.


The differences between crushing, shearing, and slicing produce varying proportions of intact and broken cells. The more thoroughly the cells are broken, the more the individual basil leaf's compounds mix and are infused with the flavor of the olive oil. A coarse pesto mixture will taste like a mouth full of leaves; a well-blended pesto will have a more ‘evolved' flavor that is at once herbaceous, nutty, and a little cheesy. Most of all, your pesto will have a smooth and supple texture.


So next time you get a craving for some of the green stuff, remember to ditch the blender and make the Ligurians proud. 



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