Garlic is the pungent bulb of an allium grown worldwide. Raw it is fierce, fried it is nutty, roasted it is sweet and soft, and it underpins savoury cooking from China to the Mediterranean.
What it is¶
Garlic is a bulb-forming member of the onion genus, Allium. Each bulb, or head, contains a cluster of cloves wrapped in papery skin. It is grown almost everywhere with a cold winter, and China produces the great majority of the world's crop.
Two main groups are grown:
- Hardneck garlic sends up a stiff flowering stalk (the scape) and has fewer, larger cloves around a woody central stem. It tends to have a more complex flavour and suits colder climates, but stores less well.
- Softneck garlic rarely flowers, has many cloves in layers and a soft stem that can be plaited. Most supermarket garlic is softneck; it keeps for months.
"Elephant garlic", with huge mild cloves, is actually a form of leek (Allium ampeloprasum). Fresh "wet" garlic, sold in early summer before it is dried, is milder and juicier. Black garlic is whole heads held at warm temperatures (roughly 60–80°C) and high humidity for several weeks; the cloves turn black, soft and sweet through Maillard browning rather than true fermentation.
Origins and history¶
Garlic was domesticated in Central Asia and is among the oldest cultivated flavourings. It was well known in ancient Egypt — garlic bulbs were found in Tutankhamun's tomb, and Herodotus reported an inscription recording the radishes, onions and garlic eaten by the pyramid builders — and in Mesopotamia, India and China. Greek and Roman writers associated it with labourers, soldiers and sailors, and many elite writers sneered at its smell.
Medieval Europe grew it widely; it was used as food and folk medicine, and folklore credited it with warding off everything from plague to vampires. In Britain it fell out of favour among the fashionable for much of the 18th and 19th centuries, and its return to everyday British cooking owed much to postwar interest in French, Italian and Indian food.
Flavour and aroma¶
Intact garlic smells of very little. Cutting or crushing lets the enzyme alliinase convert alliin into allicin, the source of raw garlic's fierce pungency, which then breaks down into a range of sulphur compounds. The more you damage the cells, the stronger the result, so flavour depends on how you cut it:
| Preparation | Strength |
|---|---|
| Whole unpeeled cloves, roasted or simmered | Mildest, sweet |
| Whole peeled or halved cloves | Mild |
| Sliced | Medium, nutty when fried |
| Chopped | Stronger |
| Crushed, grated or pounded to paste | Strongest, sharpest |
Cooking converts the harsh raw notes into sweeter, rounder flavours. Fried garlic becomes nutty and golden but turns acrid and bitter within seconds if it browns too far. Slow-roasted garlic becomes soft, spreadable and almost caramel-sweet.
In the kitchen¶
- Fry gently: in most dishes add garlic after onions have softened, and cook it for 30–60 seconds over a medium heat until fragrant — not browned. Burnt garlic is the commonest cause of bitterness in home cooking.
- Crisp garlic: slice thinly, cover with cold oil, then heat gently until pale gold, and drain; it continues to colour off the heat. Use the oil too. See chilli-crisp.
- Roast whole heads: slice off the top, drizzle with oil, wrap in foil and roast at 200°C (gas 6) for 40–50 minutes until soft.
- Confit: peeled cloves simmered very gently in oil for 40 minutes, then refrigerated.
- Raw sauces: aioli and allioli, Lebanese toum, Greek skordalia and tzatziki, pesto, gremolata, persillade, chimichurri, and mojo.
- Pastes: pounded with ginger for Indian and South Asian cooking — see ginger-garlic-paste — and as the base of many curry pastes.
- Granules and powder are useful in dry rubs and seasonings, where fresh garlic would burn; ½ tsp granules is roughly equal to one clove.
💡 Getting the smell off your hands
Rubbing your hands on stainless steel under running water, then washing with soap, is a common kitchen trick that many cooks find helps. Rinsing with cold rather than hot water first also avoids "setting" the smell.
Buying and storing¶
Keep whole heads in a cool, dry, airy place — not the fridge, which encourages sprouting and mould. Softneck garlic keeps for several months, hardneck for a few. Once a head is broken, use the cloves within a couple of weeks. A green sprout in the middle of a clove is harmless but can taste bitter; remove it if you like. Dried granules and powder keep about a year; see storing-spices.
Substitutes¶
Garlic granules or powder (½ tsp granules or ¼ tsp powder per clove). Wild garlic leaves in spring, chives or garlic chives for a milder, fresher flavour. Shallots give a sweeter allium note. For people who avoid alliums, asafoetida fried in oil provides a similar savoury depth, as in Jain and some Hindu cooking.
Pairs well with¶
Almost everything savoury: onions, tomatoes, olive oil, butter, lemon, potatoes, mushrooms, lamb, chicken, seafood, beans, soy sauce, ginger, chillies, parsley, basil, thyme, rosemary, cumin, coriander, paprika and black pepper.
Growing your own¶
Garlic is simple to grow. Plant individual cloves, pointed end up and about 2–3 cm deep, 15 cm apart, in autumn (October to November in the UK) in sunny, free-draining soil; most varieties need a cold spell to form proper bulbs. Plant garden-centre seed garlic rather than supermarket cloves, which may carry disease or be unsuited to the climate. Cut off hardneck scapes in early summer and eat them. Harvest in mid-summer when the lower leaves have yellowed, then dry the bulbs in a warm, airy place for two to three weeks before storing.
Health and safety¶
⚠️ Garlic in oil
Raw garlic stored in oil at room temperature can allow Clostridium botulinum to grow, because the oil excludes air and garlic is low in acid. Homemade garlic oil and confit should be kept in the fridge and used within about four days, or frozen. Commercial garlic-in-oil products are acidified to make them safe.
Garlic in food amounts is safe for most people, but large amounts of raw garlic can irritate the stomach, and garlic supplements may increase the effect of anticoagulant (blood-thinning) medicines — anyone taking these, or preparing for surgery, should mention supplements to their doctor. Garlic, like onion, is toxic to dogs and cats. Garlic pickled in vinegar sometimes turns blue or green; this is a harmless reaction between sulphur compounds and the pigments of the clove.