Basil pesto from the mortar: bright green, no bitterness, in twenty minutes
Real pesto alla genovese is a handful of simple ingredients and one rule: nothing is cut, everything is crushed. A blender blade slices the leaves and releases an enzyme that, meeting air, turns basil into a dark, faintly bitter paste. A mortar bruises them and presses out the oils, so the pesto stays bright green and smells of the garden. Two small jars: one for pasta tonight, one under oil for the week.
Your own work in that: 25 min.
- Basil 8 min
- Pounding 12 min
- Into jars 5 min
Step by step
0 / 6 doneWash and dry the basil
Pick the leaves off the stems (the stems are bitter), rinse in cold water and dry them completely on a cloth or in a salad spinner. Water on the leaves splits the pesto and shortens its keeping time in the jar. Put the mortar, and the blender jug if you use one, in the freezer for 15 minutes.
Ingredients: 100 g basil leaves only · 40 g pine nuts · 1 clove garlic · 60 g parmesan · 120 ml extra virgin olive oil · ½ tsp coarse sea salt
TipBasil darkens with heat and oxygen. Cold equipment, shade and working without pauses are the three things that keep the colour; that is why pesto is made in twenty minutes, not in passing.
Leaves only, dried completelyCrush the garlic with salt
Halve the clove, remove the green germ from the centre and crush it in the mortar with the coarse salt into a smooth paste, about a minute. The salt works like sandpaper here: it tears the garlic cells open faster than the pestle could alone.
TipThe green germ inside the clove is sharper and slightly bitter, and many cooks blame it for garlic that repeats on you long after dinner. Always take it out.
Salt as an abrasive, a paste in a minuteAdd the pine nuts
Add the pine nuts and pound 2 minutes, until you have a rich, creamy mass with no distinguishable pieces. Classically the nuts are raw; lightly toasted they give a deeper, nuttier flavour but a darker pesto.
Nuts to a rich, smooth pasteGrind the basil in batches
Add the basil a handful at a time, grinding it against the wall of the mortar in a circular motion rather than striking down. Work each batch in before adding the next; the whole takes 6–8 minutes. The mass should be thick, vivid green and glossy with released oils.
TipA circular motion bruises the leaf and presses the oils out; striking and cutting ruptures the cells, releases the oxidase and quickly turns pesto brown. That is the whole difference between a mortar and a blender.
A handful at a time, circling against the wallStir in the cheese and oil
Add the grated parmesan, stir, then pour in the oil in a thin stream, stirring constantly with the pestle, until the pesto is uniform and creamy. Taste and add more salt if needed. The texture: as thick as Greek yogurt, falling off the spoon in sheets.
Cheese first, then oil in a thin streamFill the jars
Spoon into two small scalded jars, press down with a teaspoon so no air pockets remain, and cover the surface with a thin layer of oil. It keeps a week in the fridge; after each spoonful, level the surface and top up the oil.
Ingredients: 2 tbsp olive oil
TipThe oil layer cuts the pesto off from the air. Without it the top goes dark in a day, even though the pesto underneath is still green.
Pressed down, sealed with oil, into the fridge
Before you start
In a blender, but cold
Chill the jug and blade in the freezer, blend in short 2–3 second pulses with pauses, and add the oil at the end. Never run it continuously: the blade heats up and the pesto browns as you watch.
Freeze it without cheese
Freeze the pesto in ice-cube trays without the parmesan; add the cheese after thawing. One cube per portion of pasta keeps 3 months and stays as green as July.
Toss with pasta, never heat it
Pesto is not cooked. Toss the drained pasta with the pesto in a bowl, loosening it with 2 tablespoons of the pasta water: the starch binds the sauce and the basil loses neither colour nor scent.