How to Cook Sichuan Boiled Fish: The Chili Oil Bath

Editor’s Note: This page has been rewritten with measured quantities, pan temperatures and the failure points that actually matter. The story behind the dish is at Sichuan Boiled Fish: The Dish Whose Name Lied to You.

Why the Broth Simmers and the Oil Pours

Shui zhu yu, 水煮鱼, is translated as water-boiled fish, and the name accounts for only one of the two cooking media involved. The fish is poached, but in broth held far below a boil. The dish is finished with oil at 200°C, poured over chopped dried chillies and Sichuan pepper at the table. Between 85°C water and 200°C oil sits the whole technique.

Fish muscle is mostly water held inside thin bundles of protein, and those proteins set between 60°C and 70°C. Past 90°C the fibres contract hard, squeeze out the water they were holding, and the flesh turns chalky in under a minute. A rolling boil also scours the egg-white and starch coating off each slice, and that coating is what keeps the fish from tasting only of broth. Held at 85°C to 90°C, the broth sets the coating into a thin jacket and firms the fish through without punishing it. Why this matters: the gap between fish poached at 90°C and fish boiled at 100°C is the gap between a slice that bends under a chopstick and one that shatters into flakes.

The oil argues the opposite case. Capsaicin and hydroxy-alpha-sanshool, the compounds behind the heat and the numbness, are fat-soluble and barely soluble in water, so simmering chillies in broth extracts almost none of what you are chasing. Hot oil does the work in five seconds. It flashes the moisture out of the chilli flesh, which is what the sizzle is, steam leaving the tissue, and carries the red pigments and aroma into the room.

Assembly follows from that. Vegetables go in first, to bulk out the dish and to lift the fish off the bottom so it does not sit in hot broth and keep cooking. Broth is ladled in only to the halfway point, then chillies, then oil. The bowl reaches the table still ticking.

Ingredients

For the fish and the velvet

• 600g firm white fish fillets (grass carp, tilapia or cod), skinned, blood line removed
• 1 egg white (30g), lightly beaten
• 1 tbsp (10g) cornstarch or potato starch
• 1 tsp (5g) fine salt, for the velvet
• 1 tbsp (15ml) Shaoxing wine
• 1 tsp (3g) white pepper

For the vegetables

• 300g bean sprouts, rinsed
• 200g napa cabbage, cut into 4cm pieces
• 1 tsp (5g) salt, for the blanching water
• 1 tbsp (15ml) neutral oil, for the blanching water

For the broth

• 1.5 litres water or unsalted chicken stock
• 2 tbsp (35g) Pixian doubanjiang, chopped fine
• 1 tbsp (15g) ginger, minced
• 3 garlic cloves (12g), minced
• 1 tbsp (15ml) light soy sauce
• 1 tsp (4g) sugar
• 2 tbsp (30ml) rapeseed oil, for frying the paste

For the chilli layer and the pour

• 30g dried chillies, ideally erjingtiao
• 2 tbsp (12g) Sichuan pepper
• 150ml rapeseed oil (caiziyou if you can get it)
• 2 scallions (30g), thinly sliced
• 1 tbsp (10g) toasted white sesame seeds

Substitution notes: Grass carp has the firmest flesh and the cleanest flavour here. Tilapia behaves almost identically and is easier to find. Cod is the most fragile of the three, so poach it for 60 seconds rather than 90 and lift it carefully. Oily fish will not work at all: the fat clouds the oil and the flesh collapses. Frozen fillets must be fully thawed and patted bone dry, or the velvet slides off in the broth.

Cornstarch and potato starch both make a good velvet; potato gives a slightly firmer jacket, and tapioca is a passable emergency substitute. Wheat flour is not. If you cannot find Pixian doubanjiang, another fermented broad-bean paste will do, but salt levels vary between brands, so taste the strained broth before adding soy. Chilli bean sauce sold as la doubanjiang is hotter and saltier, so use 1.5 tbsp. For the oil, Chinese rapeseed is traditional and peanut oil is acceptable; olive oil is neither.

Prep: What Happens Before the Wok Is Hot

1. Slice the fish 4mm on the bias (10 minutes)

Pat the fillets dry and put one flat on the board. Find the grain, the pale lines running the length of the fillet, then hold the knife at about 30 degrees to the board and cut across those lines at 4mm intervals, drawing the blade towards you in one long stroke rather than sawing. The angled cut gives a slice 5cm to 6cm across, wider than a vertical cut and more even in thickness, which is what lets it cook through in a minute without the edges disintegrating.

Work from tail to head and keep the slices in a single layer, not stacked, because stacked slices weld together and tear when separated.

2. Toast and chop the chilli layer (5 minutes)

Snip the 30g of dried chillies into 2cm sections, shaking out about half the seeds. Put them in a dry wok with 2 tbsp Sichuan pepper over medium-low heat and toss for 40 seconds. The signal is smell: dusty and papery first, then fruity. A toasted chilli bends; an untoasted one snaps. Tip onto a cold plate at once, since the wok holds enough heat to burn them. Chop the chillies coarse and crush the pepper to a gritty powder, keeping the two separate.

3. Cut the vegetables (5 minutes)

Halve the cabbage lengthwise, cut out the core, then cut across into 4cm pieces, keeping the thick stems and the leafy tops apart because the stems need 15 seconds more. Rinse the sprouts and pinch off the tails if you have the patience; it is optional. Set a colander in the sink, a fine sieve over a second pot, and a 3-litre bowl on the counter.

Step by Step: Fifteen Minutes of Cooking

Step 1: Velvet the fish (15 minutes)

Put the fish in a bowl and add the 1 tsp salt first, folding for 30 seconds until the surface feels tacky; the salt draws out water and makes a brine the egg white can bond to. Add the Shaoxing, fold, then the egg white until every slice is slick, then the starch in three additions, stopping when no dry patches remain. The bowl should look glossy, not wet. Rest in the fridge for 15 minutes exactly, or the salt starts to tighten the surface.

Step 2: Blanch the vegetables (2 minutes)

Bring 2 litres of water to a rolling boil with 1 tsp salt and 1 tbsp oil. Drop in the sprouts and count 30 seconds, then lift them out with a spider. Next the cabbage stems for 45 seconds, then the leaves for 30. Everything should be cooked but still squeak against your teeth. Why this matters: the vegetables are the bed the fish rests on, and if they are soft they collapse under its weight and turn the bottom of the bowl to mush. Drain and press gently to push out the water between the leaves, which would otherwise dilute the broth. Lay them in a loose bed in the serving bowl and salt lightly.

Step 3: Build and strain the broth (12 minutes)

Wipe the pot dry, heat 2 tbsp rapeseed oil over medium heat and add the doubanjiang. Stir constantly for 90 seconds, until the paste darkens and the oil around it turns brick red; raw doubanjiang tastes of fermented beans, fried doubanjiang tastes of the dish. Add the ginger and garlic for 20 seconds, then 1.5 litres of water or stock, the soy and the sugar. Boil, then simmer for 10 minutes. Strain through the fine sieve into the second pot, pressing the solids, and discard them. Taste for salt and heat. Bring it back to 85°C to 90°C, where small bubbles gather at the rim and none break the surface.

Step 4: Poach the fish at 85-90°C (3 minutes)

The fish goes in last because it takes 90 seconds and cannot wait. Slide the slices in one at a time, in three batches of about 200g, spread across the surface rather than dropped in a heap, and do not stir. After 30 seconds, lift the pot an inch and set it down once; that jolt releases any slice stuck to the bottom without breaking the others. Total time is 60 to 90 seconds. The slices turn from translucent pink to opaque white, firm at the edge and still yielding slightly in the centre.

Lift them with a spider, drain for two seconds, and lay them over the vegetables in overlapping rows, building a slight mound. Repeat with the remaining batches, then ladle broth over the fish to the halfway point. It should sit in broth, not swim in it.

Step 5: The chilli layer and the 200°C pour (3 minutes)

Pile the chopped chillies and crushed pepper in a band along the centre of the fish, leaving a border of white flesh at the edges, and scatter the scallions over the top. Heat 150ml rapeseed oil to 200°C. A piece of chilli dropped in should fizz at once and rise; if the oil smokes heavily before that, it has overshot. Carry the pan to the table and pour in three stages from 20cm, waiting for the sizzle to drop between them. The chillies go from dull red to dark crimson in five seconds. Scatter the sesame and serve while the oil is still moving.

Key Pitfalls

The fish broke into flakes in the broth. The broth was boiling, or you stirred. Both tear the coating and the flesh under it. Hold 85°C to 90°C, add the slices one at a time, and move the pot rather than the fish when something sticks.

The coating slid off and the broth went cloudy. The fillets were wet, or the velvet was not rested. Water stops the egg white bonding and dry starch has not hydrated. Pat the fish dry before salting and give it the full 15 minutes.

The chilli oil tasted raw and grassy. The oil was not hot enough. At 180°C the chillies soften but do not bloom, and rapeseed keeps its harsh edge. Take it to 200°C and use a thermometer rather than reading the shimmer.

The chillies turned black and bitter. They were toasted too hard, or the oil was above 210°C. Forty seconds over medium-low heat makes them pliable; past that they burn. Pour in stages so you can stop if the colour goes too far.

The bottom of the bowl was salty and the top was bland. The broth was under-seasoned and the paste was not strained, so the salt stayed in the solids. Correct the seasoning in the strained broth, then ladle it over so every slice gets some.

The vegetables were limp and greasy. They were blanched too long or left sitting in broth. Thirty seconds for sprouts, 45 for cabbage stems, and drain them properly. They should still have a bite under the fish.

The fish was overcooked before it reached the table. It was poached until fully opaque, then the 200°C oil cooked it again. Pull it at 80 percent done, while the centre still looks faintly translucent, and let the oil finish it.

Serving Suggestions

Serve it in the bowl it was assembled in, with a pot of steamed white rice alongside. The oil that pools at the bottom is far too strong to eat with a spoon, but a spoonful over rice turns each grain red and makes the heat feel deliberate. Put out black vinegar for anyone who wants to cut the oil.

Eat the fish first, while the coating is still tight, then work down into the vegetables, which by then have been sitting in seasoned oil and taste of everything. Leftover fish does not reheat well, but the oil can be strained once it cools, kept for a few days, and used to fry potatoes or aubergine. Drink cold lager or jasmine tea rather than wine; the capsaicin flattens most of it.

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This is the companion recipe to Sichuan Boiled Fish: The Dish Whose Name Lied to You. Read the story, then cook the dish.