What Can I Substitute for Lemongrass?

You're pounding or blending a Thai curry paste and the recipe calls for finely sliced lemongrass along with the chilli, garlic and shallot.

• lemongrass paste (tube or jar) — 15 ml for every 1 stalk (about 15 ml finely chopped) (3 tsp)
• lemon zest plus fresh ginger — 3 g lemon zest (about half a lemon) plus 3 g grated ginger for every 1 stalk

Here lemongrass supplies the lemon aroma, the green, gingery note and some of the paste's bulk. Lemongrass paste covers all three, and zest plus ginger covers the aroma and the warm note while adding a little body. If you measure the paste with an Australian 20 ml tablespoon you will add a third more than intended, along with its added salt.

You're simmering a tom yum, a coconut soup or a stock with bruised lengths of lemongrass that get fished out before serving.

• dried lemongrass — 5 ml for every 1 stalk (about 15 ml finely chopped) (1 tsp)
• lemongrass paste (tube or jar) — 15 ml for every 1 stalk (about 15 ml finely chopped) (3 tsp)
• makrut lime leaves — about 1 g (2 leaves) for every 1 stalk

When the stalk is only there to infuse the liquid, body does not matter and only the aroma has to come through. Dried lemongrass in an infuser does that job and comes out cleanly, paste dissolves straight in, and makrut lime leaves give a strong citrus perfume that suits the same soups but shifts it towards lime.

You're stirring finely chopped lemongrass into a stir-fry or rubbing it into a marinade for chicken, pork or tofu.

• lemongrass paste (tube or jar) — 15 ml for every 1 stalk (about 15 ml finely chopped) (3 tsp)
• lemon zest plus fresh ginger — 3 g lemon zest (about half a lemon) plus 3 g grated ginger for every 1 stalk
• lemon zest — 3 g (zest of about half a lemon) for every 1 stalk (1½ tsp)

Quick cooking keeps the citral aroma from fading, so anything that carries it works well. The paste clings to meat like pounded lemongrass, zest with ginger adds back the warm green note, and zest alone gives a plainer lemon flavour that is still pleasant in a fast stir-fry.

You're steeping lemongrass in a sugar syrup, custard, panna cotta base or pot of tea for a sweet dish or drink.

• lemon zest — 3 g (zest of about half a lemon) for every 1 stalk (1½ tsp)
• ground lemon myrtle — 1.25 ml for every 1 stalk (¼ tsp)
• dried lemongrass — 5 ml for every 1 stalk (about 15 ml finely chopped) (1 tsp)

In sweet infusions only the lemon aroma matters, and the grassy, gingery note is barely missed. Zest strips give a clean lemon scent, lemon myrtle gives a stronger one with a eucalyptus edge, and dried lemongrass in a muslin bag keeps the true lemongrass flavour and strains out cleanly.

You're making a dish where lemongrass is the main flavour, such as Vietnamese lemongrass chicken, lemongrass-crusted beef or prawn mince moulded onto lemongrass skewers.

• lemongrass paste (tube or jar) — 15 ml for every 1 stalk (about 15 ml finely chopped) (3 tsp)

Nothing really replaces it here.

When lemongrass is the flavour the dish is named for, the floral, grassy lemon note and the chewy, fragrant bits of chopped stalk are the point, and zest or lime leaves turn it into a different dish. Paste gets you partway for the flavour, but nothing stands in for the crisp fried shreds of fresh lemongrass or for the stalk used as a skewer.

Your curry or soup has hard, stringy pieces that are unpleasant to chew.

Why: Dried lemongrass or the tough outer layers of a stalk were added loose, and these never soften however long they cook.

Fix: Pour a thin soup through a sieve, or pick the pieces out of a thick curry with a slotted spoon, and next time put dried lemongrass in a tea infuser or muslin bag.

The soup tastes sharp and sour instead of fragrant.

Why: Lemon juice was used in place of lemongrass, which adds acidity but very little of the lemon scent that lives in the peel oils.

Fix: Balance the sourness with a pinch of palm or brown sugar and a splash of fish sauce, then stir in the zest of half a lemon in the last couple of minutes for the missing aroma.

The lemon flavour you could smell early on has almost disappeared by the time the dish is ready.

Why: Lemon zest loses its aromatic oils faster than lemongrass during a long simmer.

Fix: Grate in a little more fresh zest and simmer for only two or three minutes before serving.

The dish tastes bitter or medicinal, with a strong eucalyptus edge.

Why: Too much ground lemon myrtle was added, often by measuring it with an Australian 20 ml tablespoon instead of a quarter teaspoon, or it was boiled for a long time.

Can't be fixed — next time: You can soften it by adding more coconut milk, stock and a little sugar, but the bitterness will not fully go, so next time measure ¼ teaspoon per stalk and add it near the end.

How much lemongrass paste equals one stalk?

Use about 15 ml of paste for each stalk of fresh lemongrass. That is one level UK, NZ, US or Canadian tablespoon, but only three-quarters of an Australian 20 ml tablespoon, so use a 15 ml measure or three 5 ml teaspoons. Taste before adding extra salt or fish sauce, because most pastes contain some salt.

Which part of lemongrass do you use?

Use the pale, tender lower part of the stalk, roughly the bottom 10 to 12 cm. Trim the root end, peel off the tough outer layers, then slice finely for pastes and stir-fries. The green upper part is too woody to eat, but you can bruise it and simmer it in stocks or tea, then remove it.

Can I leave lemongrass out of a recipe?

You can leave it out of a dish where it is one of many aromatics, but the result will taste flatter and less lemony. Adding the zest of about half a lemon per stalk keeps most of the missing aroma. In dishes named for lemongrass, such as Vietnamese lemongrass chicken, leaving it out changes the dish completely.

Can you freeze lemongrass?

Yes, lemongrass freezes well. Slice the pale lower stalks finely, spread them flat in a zip-lock bag and freeze, then break off what you need and add it straight to the pan. Whole trimmed stalks can also be frozen for simmering in soups and stocks.

Is lemongrass the same as citronella?

No, they are related grasses but not the same plant. Lemongrass is grown for cooking, while citronella grass is mainly grown for its oil, which is used in candles and insect repellents. Do not cook with citronella products or ornamental plants sold as citronella.

Are makrut lime leaves the same as kaffir lime leaves?

Yes, they are the same leaf sold under two names. Either can stand in for lemongrass in Thai curries and soups, but they give a perfumed lime scent rather than a soft lemon one, so the dish will taste noticeably different.