- Season
- Autumn through early spring, with peak sweetness after frost.
- Price
- Low
- Nutrition per 100 g
- 61 kcal
- 1.5 g protein
- 0.3 g fat
- 14.2 g carbs
Leek
Vegetables
Leek
The leek is a cultivated allium, Allium ampeloprasum var. porrum (long treated under the synonym Allium porrum), grown for its elongated, blanched pseudostem formed by tightly layered leaf sheaths. Unlike bulb-forming onions, the leek develops a cylindrical body of pale white to light green flesh, prized for its subtle aroma and restrained pungency.
In practice
How to store
- On the counter
Not recommended, as leeks lose moisture and sweetness rapidly at room temperature.
- In the fridge
Store unwashed in the crisper drawer, loosely wrapped, for up to two weeks.
- In the freezer
Slice, blanch briefly, and freeze for up to three months for cooked preparations.
How to choose
Select leeks with firm, straight shafts and tightly wrapped layers. The white portion should be unblemished and heavy for its size, while the green tops should appear moist and resilient rather than limp. A hard, hollow stem running through the centre signals bolting and a woody core; thickness alone is usually just the cultivar, as winter leeks are naturally stout.
What to swap in
Best swap
Sweet onion combined with a small amount of scallion greens.
In a pinch
Shallot, used sparingly to avoid excess pungency.
Preparation
Leeks must be split lengthwise and washed thoroughly to remove grit lodged between layers. Trim away the root base and reserve the dark green tops for stock. Slice according to application, favoring gentle heat to preserve sweetness.
Don't toss it
The tough green leaves, often discarded, impart remarkable depth to vegetable stocks and can be dried and powdered as a seasoning.
In the kitchen
Cooking
Leeks excel when sweated slowly in butter, allowing their sugars to emerge without browning. They may be braised, gently grilled, or incorporated into soups and gratins, where prolonged cooking transforms their structure into near silk.
Goes well with
- Butter
- Cream
- Potatoes
- Thyme
- Bay Leaf
- Cheese
What it is
The leek is a cultivated allium, Allium ampeloprasum var. porrum (long treated under the synonym Allium porrum), grown for its elongated, blanched pseudostem formed by tightly layered leaf sheaths. Unlike bulb-forming onions, the leek develops a cylindrical body of pale white to light green flesh, prized for its subtle aroma and restrained pungency.
How it tastes
The flavor of leek unfolds with a soft, vegetal attack marked by gentle sulfurous sweetness rather than sharpness. The mid-palate is rounded and creamy when cooked, carrying notes of buttered greens and young onion. The finish is clean and faintly earthy, leaving a lingering suggestion of meadow grass and warm broth.
Common questions
Are leeks sweeter than onions?
Why are leeks associated with Wales?
Can leeks be eaten raw?
Deep dive
2 min read
Varieties
While often treated as a singular vegetable, leeks exhibit meaningful varietal distinctions shaped by terroir and cultivation. Winter leeks, grown in heavier soils of northern Europe, develop thick shafts and robust structure, their sweetness deepened by frost. Summer leeks, harvested young, are slimmer and paler, with a fresher, greener aroma and tender bite. In Wales and northern France, leeks are traditionally earthed up repeatedly during growth, a labor-intensive process that lengthens the blanched portion and yields exceptional delicacy. Flavor nuances range from milky and faintly floral in young leeks to mineral and savory in overwintered specimens drawn from clay-rich fields.
History
The leek’s history stretches deep into antiquity. Ancient Egypt depicted leeks in tomb paintings and placed them among grave offerings, associating them with nourishment and ritual purity. Classical Greece and Rome valued leeks both as food and medicine, with Emperor Nero reputedly consuming them to strengthen his voice. During the Medieval period, leeks traveled widely along monastic and mercantile routes, becoming a staple of European peasant cookery due to their reliability in cold climates and poor soils. By the Early Modern era, the leek had assumed emblematic status in Wales, symbolizing resilience and continuity. In Modern cuisine, leeks transitioned from subsistence fare to refined ingredient, anchoring dishes such as vichyssoise and serving as a gentle aromatic in contemporary vegetable-forward gastronomy.
Science
Leeks contain sulfur compounds similar to onions, though in lower concentration, accounting for their mildness. Slow cooking hydrolyses their inulin-type fructans into simpler sugars, enhancing sweetness. Their cell walls soften readily under moist heat, releasing soluble fibers that contribute body to soups and sauces without starch.
Sourcing and ethics
Leeks are a long-season crop: conventional production typically relies on nitrogen fertilisation and repeated fungicide treatments against leek rust, alongside insecticides for thrips and leek moth, and EU residue monitoring regularly finds multiple residues in leek samples. Sourcing from small-scale regional farms supports seasonal agriculture and reduces transport emissions. Organic cultivation further preserves soil health, particularly in rotations with legumes and brassicas.