Sweet basil is a tender annual of the mint family, prized for its warm, clove-and-anise scent. It is the soul of pesto and Italian tomato cookery, and it bruises, blackens and fades if handled roughly.
What it is¶
Sweet basil is the leafy, soft-stemmed annual most people mean when they say "basil": glossy, bright green, spoon-shaped leaves on square stems, with small white flowers in spikes if the plant is allowed to bloom. Like most of the mint family it carries its scent in tiny oil glands on the leaf surface, which is why a leaf smells of little until it is rubbed, torn or chopped.
There are dozens of cultivated varieties. The large-leaved Genovese type dominates European cooking; Napoletano has big, crinkled "lettuce" leaves; Greek bush basil forms a tight dome of tiny leaves with a sharper flavour; purple varieties such as 'Dark Opal' are milder and look striking in salads; lemon basil (Ocimum × citriodorum) and cinnamon basil carry exactly the notes their names promise. Asian relatives — Thai basil and holy basil — have their own pages.
Origins and history¶
Basil has been grown in India for thousands of years and reached the Mediterranean via the Middle East in antiquity. Its name comes from the Greek basilikon, "royal", and it has gathered a heap of contradictory folklore: some classical writers associated it with scorpions and ill fortune, while in parts of Italy a pot of basil on the windowsill was a sign of love. Boccaccio's Decameron includes the grim tale of Lisabetta, who hides her murdered lover's head in a pot of basil — the story Keats retold as Isabella, or the Pot of Basil.
Basil came into English gardens in the sixteenth century, but it remained a minor herb in Britain and northern Europe until the late twentieth century, when Italian cooking — and above all pesto — made it a supermarket staple. In Liguria, "Basilico Genovese" has held protected (DOP) status since 2005.
Flavour and aroma¶
Good sweet basil is warm and sweet, with clove (from eugenol), a hint of anise or liquorice (estragole) and a floral, slightly minty lift (linalool). The balance varies a great deal by variety and growing conditions: Genovese is high in linalool and relatively low in estragole, which gives the rounded, sweet flavour Italian cooks want, while Thai types lean heavily on anise.
Heat destroys much of the aroma. Long-cooked basil turns muted and faintly hay-like, which is why it is usually added at the end or scattered on raw.
In the kitchen¶
Basil belongs with tomatoes, olive oil, garlic, soft cheeses and summer vegetables.
- Raw: torn over tomato salads, insalata caprese, bruschetta and pizza as it leaves the oven.
- Pounded: the classic pesto alla genovese, and its French cousin pistou, stirred into Provençal vegetable soup.
- Stirred in late: tomato sauces, minestrone and ratatouille, added in the last minute or off the heat.
- Infused: in oil, sugar syrup (excellent with strawberries or peaches) or cream for ice cream.
Tear or slice basil with a very sharp knife just before use; blunt blades and early chopping bruise the leaves and turn them black. For thin ribbons (chiffonade), stack the leaves, roll them tightly and slice across. See chopping-herbs and when-to-add-herbs-and-spices.
💡 Rescue the stalks
The stalks are full of flavour. Drop them into a tomato sauce as it simmers and fish them out before serving, or blitz the tender upper stems straight into pesto.
Buying and storing¶
Buy basil with perky, unblemished leaves and no dark patches. It is a tropical plant and hates the fridge: below about 10°C the leaves blacken within a day or two. Treat a bunch like cut flowers — trim the stems, stand them in a glass of water at room temperature, out of direct sun, and loosely cover with a bag. It will keep for three to five days.
Supermarket pot plants are usually many seedlings crammed together; split the clump into three or four and repot them, and they will last far longer. Dried basil keeps its colour but loses most of the sweet top notes, so it is best reserved for long-cooked sauces. Freezing works better: blanch the leaves for a few seconds, or blitz them with olive oil and freeze in ice-cube trays (see freezing-herbs).
Substitutes¶
There is no true substitute for fresh basil in pesto or caprese. In cooked dishes, Thai basil works if you accept more anise. A mix of flat-leaf parsley with a little mint gives freshness and colour, and a pinch of dried oregano or marjoram can stand in for basil in a long-simmered tomato sauce.
Pairs well with¶
Tomato, mozzarella, garlic, pine nuts, Parmesan, olive oil, lemon, courgette, aubergine, peaches, strawberries, black pepper, oregano, parsley, mint and chilli.
Growing your own¶
Basil is a tender annual that needs warmth: sow indoors at about 20°C from March to May, and do not put plants outside until night temperatures stay above about 10°C — in Britain that usually means June. It prefers a sunny, sheltered spot, rich free-draining soil and watering in the morning rather than the evening (cold, wet roots at night invite rot and damping off).
Pinch out the growing tips just above a pair of leaves once the plant has six to eight leaves, and keep pinching; this makes a bushy plant and delays flowering, after which leaf production falls and the flavour turns more bitter. A sunny windowsill works well for most of the year (see growing-herbs-indoors), and basil roots easily from tip cuttings in a glass of water.
Common mistakes¶
- Adding it too early. Twenty minutes in a sauce and the aroma is gone.
- Refrigerating it. Cold turns leaves black; keep it on the worktop.
- Over-processing pesto. A food processor warms and bruises the leaves; pulse briefly, or use a pestle-and-mortar.