Cooking With Lemongrass: Trimming, Bruising, Mincing and When to Take It Out

Lemongrass tastes like a rich lemon without the acidity, once you get at it. Almost all the flavor sits in the lower stalk and the slight bulb at its base, and the stalk is woody and tough. So cooking with it comes down to two moves. Either you bruise the stalk, let it infuse and pull it out, or you strip it down to its tender core and mince it fine enough to eat. In a tom yum, about 5 minutes of simmering is all the stalks get.

At a glance

Buying lemongrass

America’s Test Kitchen (ATK) says to pick stalks that are green, firm and fragrant, and that very dried-out outer leaves are a sign of long storage.¹ You’ll also hear that heavy stalks beat light ones. We found no source for weight as a test, though it’s the same idea as picking a firm stalk.

Preparing the stalk

Every prep method we found starts the same way. ATK trims about an inch from the hard, woody base and cuts off enough of the green top to leave about 6 inches of stalk. Then it peels away the tough outer layers, usually three or four, to get to the pale core.¹ delicious. magazine gives the same count, three or four layers depending on how thick the stalk is.²

What comes next depends on whether anyone’s going to eat it.

If it comes out before serving: bruise it

For soups and broths, ATK crushes the prepped stalk with a meat mallet, the side of a knife or the bottom of a pan, then cuts it into lengths.¹ delicious. magazine bashes the stalk along its length with the flat of a heavy knife and says this helps release the aromatic oils.² Southeast Asian kitchens use the same idea: pounding lemongrass in a tall mortar releases its lemony flavor.

Then the stalks steep and come out. They’re commonly steeped in oil with other spices and removed, and a tied bundle can simmer in stock the same way. In Nancie McDermott’s tom yum goong for Saveur, the trimmed stalks are smashed flat, each tied into a knot, and simmered in stock with makrut lime leaves until the broth smells fragrant, about 5 minutes. They’re thrown out before the shrimp go in.⁴ A knotted stalk stays in one piece, so it’s easy to find in the pot.

If it stays in the dish: mince the core

For marinades and spice pastes, where you’ll eat the lemongrass, ATK minces the prepped stalk or slices it thin.¹ Cooks peel back the outer layers of fresh stalks to reach the tender young shoots in the center, which can be chopped fine and added straight to a dish. delicious. magazine says to slice the soft middle as finely as you can.²

You’ll often read that you should never eat lemongrass raw. We found no source for that. The real issue is texture: the outer stalk is woody and tough, which is why it’s either removed or peeled back to the core. The core itself gets eaten. In Java, the heart of young shoots is served as a side dish with rice.

Another common instruction is to blanch lemongrass for a minute and shock it in ice water to take away bitterness. None of the prep methods we read includes that step,¹⁴² and we found no source saying lemongrass needs it.

How cooks use it, with named recipes

Those amounts belong to each recipe, but they give you a fair sense of scale.

Ratio (Computed): The tom yum puts about three stalks into a two-person pot of soup, and the Vietnamese chicken works out to roughly 3 tablespoons of minced lemongrass per plump stalk.⁴⁵

Other uses with a source behind them:

• Curry pastes. In Thailand, Laos and Vietnam, cooks pound lemongrass with garlic, makrut lime leaf and other herbs into thick curry pastes. It’s also a popular part of many curries. See Thai spices and makrut lime leaves.
• Sauces and fish. In Java, leaf sheaths go into spicy sambals like sambal goreng, and into cooked fish and fish sauces. Tom yum goong pairs it with shrimp. You’ll read that lemongrass neutralizes fishy flavors the way citrus does; we found no source for that.
• Stir-fries and meats. Lemongrass is a key ingredient in Asian cooking, especially in stir-fries and meats.
• Drinks and sweets. The stems are widely used in teas and other drinks, and in Java lemongrass flavors a popular sherbet.

How long to cook it

People often say lemongrass keeps releasing flavor the longer it cooks and can take over a braise. We found no measurement either way. What the recipes do show is that a short steep is enough in a broth: McDermott’s tom yum simmers the stalks about 5 minutes before pulling them.⁴ In a longer braise, taste as it goes and pull the stalks once the broth is lemony enough.

Dried, powdered and ready-made lemongrass

Outside Southeast Asia, many cooks rely on lemongrass powder and dried stalks. ATK tested dried lemongrass in a curry paste, a Thai chicken soup and a stir-fry, using half as much dried as fresh. Dried was an acceptable substitute in the paste and the soup, though it tasted woodsier and less complex. In the stir-fry it never softened and stayed like hay. The takeaway: use dried only where there’s enough liquid for it to rehydrate.³

Some stores sell ready-made lemongrass paste and frozen chopped lemongrass. We found no published conversion for either, so check the label for added oil, salt or sugar and taste as you go. See lemongrass substitutes for other options.

Storing fresh lemongrass

ATK gives three methods:¹

You’ll also see a six-month freezer life quoted. We found no source for it; ATK’s figure is 3 months.¹ These are quality windows from a test kitchen, not food-safety limits. Lemongrass kept in oil is a different matter. Oregon State University Extension warns that herbs are low-acid foods that can carry Clostridium botulinum, and says homemade mixtures of fresh herbs in oil must be refrigerated and used within 4 days, or frozen.⁷ That guidance covers herbs in general, not lemongrass by name.

Safety

Lemongrass in food isn’t a known hazard. Kew notes that lemongrass oil can cause contact dermatitis,⁸ which matters for the concentrated oil, not stalks in a pot. See the lemongrass profile for the health evidence.

Not yet measured

• How much flavor lemongrass gives up over time in a simmer, and whether long cooking makes it harsh.
• A standard size for “one stalk.” The recipes above say “large” or “plump” and do not give a weight.
• A conversion for tube paste or frozen chopped lemongrass.
• How long lemongrass paste keeps frozen.

Related

• Lemongrass and lemongrass uses
• Lemongrass substitutes
• Lemon verbena vs. lemongrass and lemon balm vs. lemongrass
• Thai spices, makrut lime leaves and galangal