INGREDIENT KNOWLEDGE

Onion

Onions are foundational alliums that can taste sharp and sulphurous when raw, sweet and mellow when cooked, and deeply savoury when slowly browned.

What Is an Onion?

Common bulb onions belong mainly to Allium cepa. Yellow, white, red, sweet, and small pearl onions differ in pungency, sugar level, texture, and best use. Their layered bulbs store energy for the plant and contain sulphur compounds that create their characteristic aroma.

Flavor and Cooking Behaviour

Cutting breaks onion cells and releases pungent compounds. Heat softens them and converts harshness into sweetness. Sweating produces a soft, translucent aromatic base; sautéing develops more browning; long, slow cooking concentrates sweetness and creates caramelized flavours.

How to Choose and Store

Choose firm, heavy bulbs with dry skins and no soft spots, mould, or wet necks. Store whole dry onions in a cool, dark, ventilated place. Refrigerate cut onions in a covered container and use promptly. Sweet onions generally contain more moisture and may keep less well than storage onions.

Preparation

Slice with the grain for pieces that hold their shape better, or across the grain for quicker softening. Dice for sauces and aromatic bases, cut into wedges for roasting, shave thinly for salads and pickles, or purée for marinades and curry bases.

Culinary Uses

Onion is central to Filipino ginisa, French mirepoix, Italian soffritto, Indian masalas, Middle Eastern stews, Mexican salsas, Chinese stir-fries, and countless soups, stocks, sauces, curries, braises, salads, pickles, and grilled dishes.

Pairings and Substitutions

Onion pairs with garlic, ginger, tomato, herbs, chilli, butter, oil, vinegar, meat, legumes, eggs, and nearly every savoury spice. Shallot offers a finer, sweeter profile; leek is gentler; scallion is fresher and greener.

Common Mistakes

• Crowding the pan when browning onions.
• Using high heat for caramelization and burning the sugars.
• Ignoring differences between sweet, red, white, and storage onions.
• Storing cut onion uncovered.

Related Ingredients

Garlic, shallot, leek, scallion, chives, and ginger are useful ingredients to explore alongside onion.