Stocks & broths
Shengjian mantou gelatin stock
皮冻 · A collagen-rich preparation of pork skin (often combined with pig trotters) gently simmered with stock and aromatics, then chilled until it sets into a firm, sliceable, translucent jelly. The jelly is diced small and folded into the raw pork filling of shengjian mantou and related soup dumplings; during the final steam or pan-fry, the cubes melt back into a clear, savory broth that erupts from the bun when bitten.
The formula
1 part pork skin+trotters : 3 parts stock/water, simmered ~2–3 h
Per Epicurious Pi Dong: 225 g pig skin + 225 g pig trotters to 1.4 L (6 cups) chicken stock ≈ 1:3 by mass. Tougher cuts (more skin, fewer trotters) push the ratio closer to 1:4; gelatin-leaf shortcuts (Shanghai 1984, ATK) replace the long simmer with 1 cup stock + 2 gelatin leaves or 1 tbsp bloomed gelatin.
Identity
- Translucent and clear, not opaque (proper stock, not a stewed ragout)
- Firm enough to slice and dice cleanly at 4 °C; yields to a thumbnail with slight pressure
- Melts back to a thin, drinkable broth above ~60 °C
- Pale straw to light amber in color
- Savory pork-forward flavor with restrained aromatic notes from ginger, scallion, and Shaoxing wine
- Sets without any added gelatin when the skin-to-liquid ratio is correct
Ingredients
| Base | Pork skin (rind scraped, fat trimmed) | Primary collagen source; 225 g (½ lb) per 1.4 L liquid is a working baseline. |
| Base | Pig trotters (split, with skin/joints/tendons) | Boosts gelatin yield and body; optional but traditional. Adds extra collagen from tendons and bone. |
| Liquid | Chicken stock or water | Chicken stock deepens umami; water keeps the flavor a neutral pork canvas. |
| Aromatics | Ginger (sliced) | Mask the gamy edge of long-simmered skin. |
| Aromatics | Scallion (cut into segments) | Provides sweet allium lift; some recipes add scallion whites only. |
| Seasoning | Shaoxing wine | Aromatic backbone; used by ATK in the filling as well — same flavor family. |
| Seasoning | Salt | Light seasoning only — the jelly is a vehicle, not a finished broth. |
| Flavor | Optional aromatics (star anise, bay leaves, white pepper) | Add during simmer for a deeper spice note; strain out before setting. |
Method
- 1Blanch pork skin and trotters in plain boiling water for 5 minutes, then drain and rinse.A quick pre-boil draws out blood, scum, and porky off-odors so the final stock is clear and clean-tasting — opaque or gray jelly means this step was skipped.
- 2Dice the blanched pork skin into ~1 cm pieces; leave trotters whole or halved.Dicing increases surface area so the collagen leaches into the liquid efficiently; whole trotters release their joint and tendon collagen over the long simmer.
- 3Combine skin, trotters, stock, ginger, scallion, Shaoxing wine, and any spice aromatics in a clean pot; bring to a boil, then immediately drop to a bare simmer.A rolling boil emulsifies fat and proteins into the stock, making the jelly cloudy and greasy; a lazy, intermittent bubble keeps it translucent.
- 4Simmer gently, partially covered, for 2–3 hours, skimming any foam that rises.Long, gentle extraction is what dissolves collagen into gelatin; skimming preserves clarity.
- 5Strain through a fine sieve (or cheesecloth-lined colander), discard solids and aromatics, and season the hot liquid lightly with salt.Trotter fragments and skin pieces would otherwise set into a lumpy, unworkable mass; salting now (not before) prevents the salt from toughening the skin.
- 6Cool to room temperature, then refrigerate at least 4 hours or overnight until fully set into a firm jelly.The jelly must be hard enough to dice cleanly into 3–5 mm cubes for folding into the raw filling; warm or semi-set jelly will smear and not survive mixing.
- 7Unmold and dice into small cubes; fold into the seasoned pork filling just before wrapping the buns.Small cubes melt evenly during cooking and distribute soup throughout the bite; over-mixing breaks them down into a paste.
Techniques that matter
Blanching (焯水)
Removes blood, proteins, and impurities that would cloud the final jelly and taint flavor.
Lazy simmer
A vigorous boil emulsifies fat into the stock; a barely-moving surface keeps the jelly crystal-clear.
Cold-set dice
Setting the stock overnight in a shallow tray produces a uniform, easy-to-dice block rather than an uneven lump.
Short-cut with gelatin leaves (Shanghai 1984 method)
Bloom 2 gelatin leaves in cold water, dissolve into 1 cup of warm stock, and chill — yields a serviceable jelly in 2 hours instead of overnight, at the cost of authentic pork flavor.
Variations & derivatives
Classic Pi Dong (皮冻)Jiangsu / Shanghai
Pig skin + pig trotters + chicken stock with ginger, scallion, Shaoxing wine, star anise; the gold standard for shengjian and xiaolongbao.
Chicken-stock + gelatin-leaf shortcutModern home (Shanghai 1984)
Chicken drumstick stock set with bloomed gelatin leaves; pale and clean, but lacks the pork depth of the traditional version.
Chicken-stock + unflavored gelatin (ATK)American home / ATK test kitchen
1 tbsp gelatin bloomed in 1 cup water with scallion, ginger, and chicken base; quickest path to a sliceable jelly.
Modernist Umami Gelatin (Modernist Pantry)Modernist home
Chicken stock fortified with onion, scallion, garlic, ginger, lemongrass, mirin, tamari, white miso, and beef gelatin — richer, more layered, but departs from the pure pork-canon.
Used in these dishes
Substitutions
- Pig trotters → Extra pork skin (increase by ~50%) — Maintains set, slightly less body and mouthfeel; no other protein substitute gives the same tendon-derived gelatin.
- From-scratch pork-skin stock → Store-bought chicken stock + bloomed gelatin leaves or powdered gelatin — Faster and foolproof, but flavor is chicken-led rather than pork-led; acceptable for home use, not for dim-sum parlors.
- Shaoxing wine → Dry sherry or mirin (us less) — Mirin adds sweetness; sherry is the closer match. Skip if strict.changes result
- Pork skin → Agar-agar — Sets firmer and clearer but melts at a higher temperature and produces a stiffer, less silken broth — not ideal for soup dumplings.changes result
Troubleshooting
Jelly is too soft to dice — slumps when unmolded
Not enough collagen (too much liquid, too little skin, or trotters omitted and not compensated) → Re-melt the soft set, add 1–2 additional gelatin leaves per 250 ml liquid, or extend the original simmer; next time increase skin to ~1:2 with water.
Jelly is cloudy or gray with a porky off-odor
Skipped the blanch, simmered at a hard boil, or failed to skim foam → Strain through cheesecloth while still warm; for the next batch, blanch 5 minutes and keep the simmer at a bare bubble.
Jelly is rubbery or chewy rather than silken
Over-reduced — liquid dropped below the collagen threshold and gelled too firmly → Re-melt with a splash of stock and re-set; calibrate the next batch with a 1:3.5 skin-to-water ratio for a softer set.
Buns leak broth during pan-frying or come out dry
Jelly cubes too large (didn't melt through) or filling was over-mixed and the cubes broke down unevenly → Dice to a uniform 3–5 mm; fold gently at the very end and wrap the buns without delay.