Basil comes in many different varieties: Thai, Genovese, holy, opal, purple, and more. No matter what specific type of basil you are using, be sure to smell it first. The basil should have a pungent, aromatic smell that almost “tickles” the inside of your nose.
Basil can be simply cleaned and torn into pieces to add to a sauce, cut into shreds to finish a salad or garnish a dish, or made into pesto, a classic sauce made from basil, olive oil, garlic, nuts, and cheese.
Handling Basil
The traditional basil variety for pesto is Genovese. This variety has much smaller leaves than the Italian basil you most commonly find in the market. The leaves have a strong aroma, too.
Fresh basil is fragile. The leaves will start to turn limp and even darken to black within a very short time. Chilling this herb too much actually speeds this process and robs the herb of its flavor, although you can store it for a day or two loosely wrapped in a lightly dampened towel inside a plastic bag (but don’t close the bag tightly).
Cleaning Fresh Basil
- Pull the leaves away from the stems; this is known as “picking” the leaves. Put the leaves in a bowl or sink filled with cold water and gently swish them around. A lot of dirt can hide on the back of the leaves, so check a few to make sure they are all clean.
- Lift the leaves out of the water and check the bottom of the bowl or sink by running your fingertips over the bottom; you should not feel any bits of grit. If you do, refill the bowl, add the leaves to rinse again, and check the water again.
- Keep repeating this process until the leaves (and the water) are clean.
- Transfer the leaves to a salad spinner and spin them dry.
Keeping Basil Bright
Basil can lose its fresh, vibrant green color when you make it into pesto, although you can improve the color by blanching the leaves in boiling water. Be sure to remove them after just a few seconds to retain the most flavor.
Put the blanched leaves into a bowl of ice water immediately to stop them from overcooking.
Making Pesto
A really great pesto has a good balance of flavors. This isn’t always easy when you are dealing with seasonal produce, like basil.
Garlic is an important ingredient in pesto. However, its flavor intensifies in the pesto over time, so if you are making a large batch of pesto that you plan to store for a few days, you may wish to blanch the garlic first to remove any harsh or bitter flavors. If you are going to be using the pesto right way, you can skip this step.
Nuts are another important part of a pesto. The traditional pesto from Genoa incorporates pine nuts (pignoli). Almonds and walnuts are also commonly used to make pesto.
Preparing Pesto
- Pick and clean the basil leaves (as well as any other greens, like arugula or spinach), slice the garlic very thinly (and blanch if desired), and grate the cheeses.
- Transfer the basil (and any other herbs or greens you want to add), pine nuts (or other nuts), and garlic to a food processor or a blender. (See below for the mortar and pestle method.) Chop them on low speed until they are of a relatively even size. With the machine running, add the olive oil in a stream. The pesto should be a bright green, lighter in color than the leaves were.
- Open the lid and add the cheese. Pulse the machine on and off just enough to blend in the cheese. If you run the machine at high speed or for too long, the sauce will start to change color.
- The pesto is ready to use right now, or you can transfer it to a storage container. Even out the top of the pesto to make a smooth layer, and pour a bit of olive oil on top; this will keep the pesto from turning a dark color (oxidizing). Do this before storing the pesto in the refrigerator and after each use.
