Cuts

Knife Cuts — Regional & Global

Lemongrass — Bruise, Knot & Thin Slice

Also: bruised lemongrass, lemongrass knot, lemongrass coin, lemongrass paste prep, ta-khrai

Three distinct Thai preparations of a single stalk — bruising for infusion, knotting for slow-simmers, and paper-thin cross-slicing for pastes and raw salads — each calibrated to how deeply the volatile oils should be released.

Lemongrass (Cymbopogon citratus) is one aromatic treated three fundamentally different ways depending on the desired release rate of its citral, citronellal, and geraniol compounds. Bruising (smashing with the flat of a knife or a pestle) ruptures cell walls to release oils quickly into a hot liquid. Knotting ties a trimmed stalk into a loose overhand knot so it simmers in a soup or curry without disintegrating, infusing gently while remaining removable. Thin cross-slicing (1–2 mm rounds or half-moons from the inner pale core) is used only for curry pastes and raw salads where the fibrous tissue will be either pounded to a fine paste or eaten directly. All three preparations use only the lower 10–15 cm of the stalk — the inner pale core — after the fibrous outer leaves and the dry upper green section are stripped away.

In photos

Lemongrass — Bruise, Knot & Thin Slice in its raw whole-cut form on a butcher's board — Lemongrass (Cymbopogon citratus) is one aromatic treated three fundamentally different ways depending on the desired release rate of its citral, citronellal, and geraniol compounds. Identifying traits: High volatile oil content concentrated in the lower inner core, Citrus-lemon fragrance with floral and ginger-like undertones, Fibrous cell structure requires deliberate technique to open cell walls.
Lemongrass — Bruise, Knot & Thin Slice in its raw whole-cut form on a butcher's board — Lemongrass (Cymbopogon citratus) is one aromatic treated three fundamentally different ways depending on the desired release rate of its citral, citronellal, and geraniol compounds. Identifying traits: High volatile oil content concentrated in the lower inner core, Citrus-lemon fragrance with floral and ginger-like undertones, Fibrous cell structure requires deliberate technique to open cell walls.
Where the lemongrass — bruise, knot & thin slice lives on the source. The lower third of a Cymbopogon citratus stalk.
Where the lemongrass — bruise, knot & thin slice lives on the source. The lower third of a Cymbopogon citratus stalk.
Lemongrass — Bruise, Knot & Thin Slice prepared the canonical way — Tom kha gai. PREP (all methods): Peel away the two or three outermost papery sheaths. Trim the dried root base flush. Cut off the upper green stalk leaving a 12–15 cm pale section. You now have the inner core ready for any of the three preparations.
Lemongrass — Bruise, Knot & Thin Slice prepared the canonical way — Tom kha gai. PREP (all methods): Peel away the two or three outermost papery sheaths. Trim the dried root base flush. Cut off the upper green stalk leaving a 12–15 cm pale section. You now have the inner core ready for any of the three preparations.

Where it comes from

The lower third of a Cymbopogon citratus stalk. Remove the outermost 2–3 papery sheath layers, trim the dried root end, and discard the upper green fibrous portion (which is too tough to cook usefully). What remains is a cylindrical, pale ivory-to-yellow core 10–15 cm long.

High volatile oil content concentrated in the lower inner coreCitrus-lemon fragrance with floral and ginger-like undertonesFibrous cell structure requires deliberate technique to open cell wallsFlavour and aroma degrade rapidly after cutting — use immediatelyInedible in large pieces; must be removed before serving or ground to imperceptible pastePairs with galangal, kaffir lime leaf, and chiles as the tripartite base of Thai aromatic pastes

Best for

Tom kha gai and tom yum goong (bruised stalks)Thai green, red, and massaman curry pastes (thin-sliced then pounded)Lemongrass-infused broths and coconut milk soups (knotted)Laab and Thai larb herb mixes (thin-sliced raw)Vietnamese pho and bun bo hue aromatics (bruised)Southeast Asian marinades for grilled chicken and fish

How to cook it

  1. 1PREP (all methods): Peel away the two or three outermost papery sheaths. Trim the dried root base flush. Cut off the upper green stalk leaving a 12–15 cm pale section. You now have the inner core ready for any of the three preparations.
  2. 2BRUISE: Lay the trimmed core on a cutting board and use the flat side of a large knife or a rolling pin to strike it firmly 3–4 times along its length. You will see and smell the oils immediately. Add to hot oil, soup, or broth. Remove before serving.
  3. 3KNOT: Bend the trimmed core into a loose loop and tuck one end through to create a simple overhand knot. Drop directly into soups or curries at the start of cooking. Remove with tongs before serving — it will have softened and released flavour but is still too fibrous to eat.
  4. 4THIN SLICE (paste): Slice the inner core into very thin rounds, 1–2 mm, on a cutting board with a sharp knife. For curry paste, transfer slices to a mortar and pound with salt until a fibrous paste forms, then add remaining aromatics. For raw salads (larb, som tum variations), cut on the bias and include only in very thin slices since the fibre is noticeable when eaten whole.
  5. 5PASTE MINCE: For quick curry paste without a mortar, thin-slice then run through a food processor with a little water; scrape down repeatedly. The result will be slightly coarser than stone-ground paste but acceptable.

Prep & butchery

  • Always use only the bottom 10–15 cm pale inner section; the upper green is fibrous and flavourless.
  • Chill the stalk briefly in the refrigerator before thin-slicing — the cold firms the fibre and allows cleaner knife cuts.
  • When pounding for paste, add a pinch of salt early; the abrasion aids fibre breakdown.
  • Frozen whole stalks can be grated directly on a Microplane for a paste-ready fine mince without slicing.
  • Bruised stalks can be submerged in coconut oil and refrigerated for up to a week as an infused cooking oil.

Substitutes

  • Lemon zest + fresh ginger

    Approximate the citrus-ginger register; lacks the true lemongrass camphor-floral note. Ratio: 1 tsp zest + 1/4 tsp grated ginger per stalk.

  • Dried lemongrass powder

    Use for paste applications only; flavour is duller and lacks fresh volatile oils. 1 tsp powder ≈ 1 fresh stalk for paste.

  • Frozen lemongrass (pre-sliced)

    Adequate for pastes and cooked dishes; bruising is less effective on thawed tissue. Do not use for knotted whole-stalk applications.

Related cuts

  • Galangal coin cut

    Companion thick-coin cut used in the same soups; galangal is always removed before serving, as is the knotted lemongrass.

  • Kaffir lime leaf chiffonade

    Paired aromatic; centre rib removed, leaf stacked and sliced into fine ribbons for raw salads and finishing.

  • Ginger bruise

    Analogous bruising technique for ginger in Chinese and Vietnamese broths.

Appears in

Tom kha gaiTom yum goongThai green curry (gaeng keow wan)Thai red curry pasteMassaman curryVietnamese bun bo hueLemongrass chicken (gai yang)Laab moo (Thai pork larb)

References

  1. 1.Thai Food — David Thompson
  2. 2.Simple Thai Food — Leela Punyaratabandhu
  3. 3.The Flavour Bible — Karen Page & Andrew Dornenburg
  4. 4.Hot Sour Salty Sweet — Jeffrey Alford & Naomi Duguid

Confidence: high

Notes

Why the outer sheaths matter

The outermost papery sheaths contain little volatile oil and add a papery off-note to infusions if left on. Stripping to the pale inner core is not about aesthetics — it delivers a cleaner, brighter lemongrass flavour without the dry-hay aftertaste.

Knotted vs. bruised in soups

A knotted stalk releases oils slowly and steadily over 20–30 minutes; a bruised stalk releases a burst of aroma in the first 2–5 minutes of contact with hot liquid. Use knotted for long-simmered broths where you want background citrus warmth; use bruised when you want forward lemongrass fragrance in a quickly made tom yum.