DUKAI
The Ingredient Library

Fruit

Lemon

Citrus × limon

The kitchen's sharpest tool: juice for acidity, zest for perfume, and the fruit that finishes fish, vegetables and almost everything else.

Also
Limone, Lemons
Family
Rutaceae (citrus family)
A small lemon tree heavy with yellow fruit in a field

How to recognise it

In the garden and in the hand.

  • A small lemon tree heavy with yellow fruit in a field
    growingThe tree: a small evergreen carrying fruit through winter. Burj Bhalaike, Punjab.
  • A single ripe yellow lemon hanging among glossy dark green leaves
    identifying featuresThe fruit on the branch: oval, nippled at the tip, among glossy leaves. Florence.
  • An open white lemon flower with orange stamens and a purple-flushed bud beside it
    identifying featuresFlowers: white and waxy, flushed purple in bud, intensely fragrant.
  • A whole lemon beside a halved lemon showing its segments, on a dark background
    preparedIn the kitchen: whole and halved.
Growth habit
A small evergreen tree, three to six metres high, with an open, often thorny crown; it flowers and fruits through much of the year.
Leaves
Oval, glossy, dark green leaves with a faintly winged stalk and a citrus scent when crushed.
Stem
Grey-barked branches, often with short sharp thorns at the leaf joints; young shoots are reddish.
Flower
White, five-petalled, waxy flowers flushed purple on the outside, intensely fragrant, in small clusters.
Colour
Fruit green when immature, ripening to bright yellow; the rind is dimpled with oil glands.
Aroma
Sharp, clean citrus from the oil in the rind; the leaves and flowers smell of it too.
Texture
Firm, glossy rind over a white pith and segmented juicy flesh.
Distinguishing features
Oval yellow fruit with a nipple at the tip, purple-flushed white flowers, thorny branches and scented leaves.
Common lookalikes
Citron has a thicker pith and larger, knobbly fruit. Lime is smaller, green and rounder. Ornamental citrus can look similar; the fruit and scent decide it.

In the garden

Growing and harvest.

Conditions
Full sun, shelter from frost and wind, free-draining soil and regular feeding; a container tree where winters are cold.
Season
Trees carry flowers and fruit together, and fruit can be picked over many months; the main harvest falls in winter and spring in most regions. Seasons vary by region and climate.
Harvested part
The fruit; the leaves are used in some cuisines for scent.
Ready when
Full yellow colour, a slight give in the hand, and a heavy, juicy feel.

In the kitchen

Flavour and use.

Flavour
Sharply acidic with a clean, bright bitterness in the pith; the zest is aromatic rather than sour.
Aroma
The rind's oil: floral, sharp and immediately recognisable.
Texture
Juicy segments; fine oily zest; bitter white pith.
Edible parts
Juice and zest; the whole fruit when preserved in salt; the leaves for scenting.
Preparations
Juice to finish a dish, Zest into pasta, risotto and cakes, Preserved whole in salt, Candied peel, Salsa and gremolata
Techniques
Zesting, Juicing, Preserving in salt, Candying, Roasting alongside fish and chicken
Pairs with
Olive oil, Fish and shellfish, Artichoke, Chicken, Parsley, Butter
How Paul uses it
Lemon runs through the Recipes page, with preserved lemon in Polpo alla griglia and lemon in the crab ravioli, and bowls of lemons sit in the photographs on The Table and the Library.

Selection and storage

Choosing, keeping, preserving.

Choosing
Heavy for its size, fine-grained bright skin with a slight give; thin-skinned fruit yield more juice.
Storage
A week at room temperature, three or four in the fridge; cut lemon keeps a few days wrapped.
Preserving
Preserved in salt for months; juice frozen in portions; zest dried or frozen; peel candied.

Traditional uses, nutrition and current evidence

What is known, and how well.

Each statement carries its evidence level in words and a numbered source. Nothing here recommends an ingredient as a treatment.

Nutrition

  • Established nutritional fact

    Lemon juice is a rich source of vitamin C and of citric acid, with small amounts of potassium; the zest carries flavonoids and aromatic oils. [1] [2]

Traditional use

  • Traditional use, not clinically established

    Lemons were carried on ships from the eighteenth century onward to prevent scurvy, a use that later research explained through their vitamin C content. [2]

Current evidence

  • Supported by human research

    Vitamin C is an essential nutrient needed for collagen formation, wound healing and iron absorption from plant foods, and lemon juice is a practical dietary source of it. Eating lemons does not prevent colds or treat infections. [2]

Safety and cautions

Before you cook with it.

  • Lemon is safe for most people as food.
  • Frequent sipping of lemon juice or lemon water erodes tooth enamel because of its acidity; rinse with water afterwards rather than brushing immediately.
  • Lemon and lime juice or peel on the skin followed by sunlight can cause phytophotodermatitis, a burn-like rash, in some people. Wash hands after handling large quantities before working in the sun.
  • Citrus allergy is uncommon but exists.

This ingredient profile is provided for culinary and general educational purposes. It is not medical advice and does not recommend an ingredient as a treatment. Anyone who is pregnant, managing a medical condition, allergic, or taking medication should consult an appropriate healthcare professional before using concentrated herbal preparations or supplements.

Elsewhere on DUKAI

Also in the library

Sources and review

  1. 1USDA FoodData Central, Lemons, raw, without peelNational food-composition database
  2. 2National Institutes of Health, Office of Dietary Supplements, Vitamin C fact sheetGovernment health agency
  3. 3Hankinson A, Lloyd B, Alweis R. Lime-induced phytophotodermatitis. Journal of Community Hospital Internal Medicine Perspectives. 2014;4(4):25090.Peer-reviewed case report and review
  4. 4Lussi A, Jaeggi T. Erosion: diagnosis and risk factors. Clinical Oral Investigations. 2008;12(Suppl 1):5-13.Peer-reviewed review

Sources reviewed 9 September 2026. Culinary and general educational information.

Photograph credits