There are ingredients that flavour a dish, and there are ingredients that define a cuisine. Lemongrass is the latter. Its clean, citrusy fragrance is so immediately and unmistakably Thai that a single stalk, bruised and dropped into a hot pan, is enough to transport you — to a street food stall in Chiang Mai, a family kitchen in Isan, a floating market on the canals outside Bangkok. No other ingredient captures the essence of Thai cooking quite so completely, or quite so instantly.
A Plant With Deep Roots
Lemongrass — known in Thai as ตะไคร้ (takrai) — is a tall, fibrous grass that grows abundantly across Southeast Asia, thriving in the tropical heat and rainfall of Thailand's plains and hillsides. It has been cultivated and used in Thai cooking, traditional medicine, and Buddhist ritual for centuries, long before it became a fashionable ingredient in restaurant kitchens around the world.
The plant itself is unassuming to look at — a dense clump of long, pale green stalks with a bulbous white base and rough, papery outer leaves. It is the inner core of those stalks, pale and tightly layered, that holds the essential oils responsible for its extraordinary fragrance. Those oils — primarily citral, the same compound that gives lemon its characteristic scent — are released when the stalk is bruised, sliced, or pounded, flooding the air around it with a fragrance that is simultaneously citrusy, floral, and faintly herbal, with none of the sharpness of actual lemon.
How Lemongrass Works in Thai Cooking
Lemongrass appears in Thai cooking in several distinct forms, each suited to a different purpose. Understanding those forms is key to using it well.
In curry pastes — including ONOFF's red, green, Panang, and massaman pastes — lemongrass is pounded into the paste along with the other aromatics, its fibres broken down completely so that its flavour infuses the entire dish without any texture remaining. This is where lemongrass does its deepest work, contributing a fragrant citrus backbone that underpins everything else in the paste.
In soups and broths — like the famous tom yum and tom kha — lemongrass stalks are bruised with the back of a knife and added whole or in large pieces to the simmering liquid, infusing the broth with flavour before being removed before serving. The bruising is essential: an unbruised stalk releases very little of its fragrance. A well-bruised one perfumes the entire pot.
In salads and stir fries, lemongrass is sliced as finely as possible — the inner white core only, the outer leaves discarded — and used raw or briefly cooked. At this fineness it becomes almost translucent, contributing both flavour and a very subtle texture to the finished dish.
Lemongrass Beyond the Kitchen
In Thailand, lemongrass has never been confined to cooking alone. It has been used for centuries in traditional medicine as a digestive aid, an antimicrobial, and a treatment for fever and inflammation — properties that modern research has increasingly supported. Lemongrass tea, made from the fresh or dried leaves steeped in hot water, is a common household remedy across Thailand and much of Southeast Asia, valued for its calming, digestive, and antioxidant qualities.
The essential oil extracted from lemongrass is widely used in aromatherapy and natural skincare, and the plant's natural insect-repelling properties have made it a fixture in Thai gardens and outdoor spaces for generations. In a country where the boundary between food, medicine, and ritual has always been porous, lemongrass moves comfortably between all three.
Lemongrass and the Thai Flavour Balance
Within Thai cuisine's celebrated five-flavour framework — sweet, sour, salty, spicy, and bitter — lemongrass does not fit neatly into a single category. It is primarily aromatic, contributing fragrance and brightness rather than a dominant flavour note. But that aromatic quality performs a structural function: it lifts the other flavours around it, creating the sense of freshness and aliveness that distinguishes Thai cooking from cuisines built on earthier, slower spice profiles.
This is why lemongrass appears in almost every category of Thai dish — in soups, in curries, in salads, in marinades, in dipping sauces, and in desserts. It is not a specialist ingredient with a narrow application. It is a constant presence, threading through the entire cuisine like a single fragrant note that ties everything together.
Choosing and Storing Lemongrass
Fresh lemongrass is increasingly available in supermarkets across Europe, and its quality matters. Look for stalks that feel firm and heavy, with a pale, tightly packed inner core and no signs of drying or browning at the cut end. The outer leaves should be intact — they protect the inner stalk and keep it fresh longer.
At home, lemongrass keeps well in the refrigerator for up to two weeks, wrapped loosely in a damp cloth or paper towel. It also freezes beautifully — whole stalks can be frozen and used directly from frozen in soups and curries, losing very little of their fragrance in the process.
When preparing lemongrass, remove the tough outer layers until you reach the pale, smooth inner stalk. For pastes and fine slicing, use only the bottom third of the stalk where the essential oils are most concentrated. The upper, greener portion is too fibrous to eat but makes an excellent addition to stocks and broths.
An Ingredient That Earns Its Place
Some ingredients are interchangeable. Lemongrass is not. There is no substitute that replicates its particular combination of citrus fragrance, herbal freshness, and aromatic depth — and no Thai kitchen, whether in Bangkok or Brussels, should be without it.
It is the ingredient that, more than any other, makes Thai food smell like Thai food. And in a cuisine where fragrance is as important as flavour, that is everything.
Lemongrass and Ginger Chicken Soup
Cooks in 35 minutesThis is Thai comfort food at its most aromatic and most elegant — a clear, fragrant broth built on fresh lemongrass, ginger, and kaffir lime leaves, with tender pieces of chicken and a seasoning of ONOFF's No Fish Vegan Seasoning Sauce that gives the soup its gentle, rounded depth. Lighter than tom kha and simpler than tom yum, this soup lets lemongrass speak clearly and without competition. It is the kind of dish that feels restorative the moment the fragrance reaches you — warming, clean, and deeply satisfying.
