Bacalao al Pil Pil: The Definitive Traditional Basque Recipe

Bacalao al pil pil is, probably, the dish that best defines Basque cuisine. Three ingredients. No thickener. A sauce that comes from the fish itself and has been challenging chefs around the world for centuries. If you've ever wondered how such a simple dish can be so difficult to master, this guide gives you all the answers.

Here you will find no shortcuts or tricks that distort the dish. What you will find is the bacalao al pil pil recipe truly explained: with exact temperatures, the methods used by Arguiñano and Berasategui, why the "penca" cut is the star, how to rescue a sauce that has split, and everything you need for it to come out perfect from the very first time.

What is bacalao al pil pil and why is it so fascinating?

Bacalao al pil pil is a dish from the Basque gastronomic tradition in which cod loins are slowly cooked in olive oil flavored with garlic. Its name mimics the soft sound -- pil, pil, pil -- that the oil makes when bubbling at low temperature in the earthenware casserole.

What makes pil pil a fascinating dish is its sauce. It contains no flour, no egg, no cream, nor any external thickener. The sauce forms because the cod skin releases collagen which, when hydrolyzed into gelatin, emulsifies with the olive oil through mechanical movement. It is, essentially, a fish mayonnaise made without egg.

This apparent simplicity hides a real difficulty. If the oil is too hot, the gelatin denatures. If the cod has no skin, there is no collagen. If you don't move the casserole correctly, the emulsion won't form. Every detail counts, and that's why pil pil is considered one of the acid tests of Spanish cuisine.

History of pil pil in Basque cuisine

The origin of bacalao al pil pil dates back to the Basque Country in the early 19th century, specifically in the kitchens of the Vizcayan *arrantzales* (fishermen). Oral tradition has it that the dish was born by accident: a cook who was confiting cod in oil noticed that, when he moved the casserole, the oil mysteriously thickened. What seemed like a mistake turned out to be one of the greatest discoveries in Spanish gastronomy.

Cod arrived in the Basque Country from Newfoundland, Iceland, and Norway, brought by the Basque fishermen themselves who were the first Europeans to exploit the North Atlantic fishing grounds. Salted on board for preservation, cod became an essential protein in the Basque diet, especially during Lent and Fridays of abstinence.

The gastronomic societies (txokos) of San Sebastián and Bilbao were the laboratory where pil pil was perfected. In these spaces, groups of men cooked and shared recipes, turning the preparation of pil pil into a ritual passed down from generation to generation. Each txoko had its technique: some moved the casserole in circles, others back and forth, and debates about the correct method were endless.

Today, bacalao al pil pil is present on the menu of practically all Basque restaurants, from cider houses to Michelin-starred establishments. In 2023, the Royal Basque Society of Friends of the Country included it among the ten dishes that define Basque culinary identity.

The science of emulsion: why it thickens without egg or flour

Pil pil sauce is an oil-in-water emulsion, similar to mayonnaise. But while mayonnaise uses egg lecithin as an emulsifier, pil pil uses cod collagen.

Here's what happens step-by-step inside the casserole:

1. Collagen hydrolysis (50-70 C). Cod skin contains large amounts of type I collagen. When heated between 50 and 70 degrees, the collagen fibers break down and transform into soluble gelatin that dissolves in the oil.
2. Albumin release. The cod flesh releases small amounts of albumin (that whitish substance you see coming out), which acts as a co-emulsifier and stabilizes the mixture.
3. Mechanical emulsification. By moving the casserole, the movement breaks the oil into micro-droplets. The gelatin positions itself at the interface between the water and the oil, with its hydrophilic part oriented towards the water and its hydrophobic part towards the oil, preventing the droplets from regrouping.
4. Stabilization. As more gelatin is incorporated, the emulsion becomes more stable and the sauce gradually thickens until it reaches the consistency of a light mayonnaise.

There are two critical temperature thresholds. Below 50 C, collagen does not hydrolyze, and the skin does not release gelatin. Above 80 C, gelatin denatures and loses its emulsifying capacity. The operational window is narrow -- between 55 and 70 C -- which is why temperature control is the most important factor for pil pil.

Cod from cold waters (Iceland, Norway) accumulates significantly more collagen than cod from warm waters, because collagen acts as thermal insulation. This explains why Icelandic cod is superior for pil pil: more gelatin, easier emulsion, and a fuller-bodied sauce.

Which cod to choose: penca, kokotxas, tail, and loin

The choice of cut is the most influential factor in the difficulty and outcome of pil pil. Not all cuts release the same amount of gelatin, and the difference between success and failure starts at the fishmonger.

Penca (the star piece for pil pil)

The penca is the thickest part of the loin, near the head. It is the piece that concentrates the most gelatin after the kokotxas: its skin is thick, its flesh firm, and its thickness (4-5 cm) allows for slow cooking without falling apart. If you are only going to buy one cut for pil pil, make it penca. At Bacalalo, we sell it specifically selected for pil pil.

Kokotxas (guaranteed emulsion)

Cod kokotxas are the muscle from the lower jaw and contain an extraordinary concentration of gelatin. They emulsify in half the time of loins and produce a denser, creamier sauce. They are the preferred piece in Basque gastronomic societies, although their price is higher.

Central loin

The central loin fillets offer a good balance between flesh and gelatin. They are slightly thinner than the penca (3-4 cm), which requires more careful temperature control to prevent them from falling apart before releasing enough collagen.

Tail

The tail has less gelatin and is thinner, which increases the difficulty. However, it is the most economical cut and, with patience, also produces a good emulsion. The trick is to add one or two loose kokotxas to the oil to boost the collagen contribution.

Comparative table of cuts for pil pil

Non-negotiable requirements for pil pil: the cod must have skin (no skin, no emulsion), a minimum thickness of 3 cm (thin pieces fall apart), and be well desalted (36-48 hours changing water). If you don't want to risk desalting yourself, professionally desalted cod comes with the exact salt point.

Special Pil Pil Penca (2 pcs) - 500g

13,90 EUR

Desalted Cod Kokotxas - 500g

19,90 EUR

Clean Dried Cod Tail - 400g

11,90 EUR

Ingredients for 4 people

• 4 pieces of desalted cod penca with skin -- between 180 and 220 g each, minimum 3 cm thick. Alternatively, 800 g of desalted kokotxas.
• 300 ml of mild extra virgin olive oil -- Arbequina, Hojiblanca, or Empeltre. Young Picual oil is too intense and masks the cod.
• 6 large garlic cloves -- cut into thin 2 mm slices.
• 1-2 dried cayenne peppers -- optional, cut in half and deseeded for a subtle spice.

Nothing else. If you see recipes that add flour, broth, or parsley, they are not pil pil: they are green sauce or hybrid preparations. Authentic pil pil exclusively uses these three ingredients (four with the chili). If you start with salted cod instead of desalted, you will need 36-48 hours of soaking beforehand; consult our guide on how to desalt cod correctly.

Bacalao al pil pil recipe step by step

This is the traditional bacalao al pil pil recipe, the one made in Basque txokos. Total time: 40-50 minutes. Difficulty: medium-high.

1. Dry the cod very well (5 minutes). Remove all moisture from the surface with kitchen paper, paying special attention to the skin. Water is the enemy of emulsion: it prevents gelatin from dissolving properly in the oil. Leave the pieces at room temperature for 15 minutes before starting.
2. Confit the garlic and chili (4-5 minutes). Pour the 300 ml of olive oil into a wide earthenware casserole. Heat over very low heat, add the garlic slices and chili peppers. Brown them slowly until golden but never burned (burned garlic will make the whole preparation bitter). Remove them with a slotted spoon and set aside on a plate.
3. Check the oil temperature. The oil should be between 60 and 70 degrees: it should not smoke or bubble vigorously. If you insert the wooden handle of a spoon, it should produce fine, gentle bubbles. If the bubbles are large and violent, remove from heat and wait 2 minutes.
4. Place the cod with the flesh side down (8-10 minutes). Place the pieces with the skin facing up and the flesh in contact with the oil. Do not move them during this time. You will see the surface begin to release a whitish substance: this is the albumin and gelatin beginning to be released. Keep the heat to a minimum.
5. Carefully flip them over (5-7 minutes). With the help of a wide slotted spoon, flip each piece so that the skin is at the bottom, in direct contact with the oil. The skin is the main source of collagen: this direct contact accelerates gelatin release. Cook for 5-7 more minutes without touching.
6. Remove the cod. Carefully take the pieces out and place them on a plate preheated in the oven at 60 degrees. Cover them with aluminum foil. In the casserole, the oil loaded with gelatin remains: this is where the magic happens.
7. Lower the oil temperature. Remove the casserole from the heat and wait 1-2 minutes. The oil should cool to about 55-60 degrees. If you have a kitchen thermometer, use it: this step makes all the difference.
8. Emulsify the sauce (8-15 minutes). Take the casserole with both hands and begin to move it with circular and back-and-forth motions, without using any utensils. Do not stir with a spoon or whisk. The movement should be constant but gentle: imagine you are shaking a pan to make a crepe. The oil will begin to become opaque and thicken gradually.
9. Use thermal contrast if it doesn't thicken. If after 5 minutes the sauce shows no signs of emulsifying, place the casserole over low heat for 10-15 seconds and then remove it again. This thermal contrast usually unlocks the emulsion. Repeat as many times as necessary, always alternating seconds on the heat and half a minute off.
10. Return the cod and plate. When the sauce has the consistency of a light mayonnaise — opaque, creamy, coating the back of a spoon — return the cod pieces to the casserole, generously coat them with the sauce, sprinkle the golden garlic and chili peppers on top, and serve immediately in the earthenware casserole itself.

Arguiñano method vs. Berasategui method

Karlos Arguiñano and Martín Berasategui represent two schools of pil pil. Both Basque, both renowned, but with distinct techniques worth knowing.

Arguiñano's pil pil: tradition and patience

Karlos Arguiñano advocates the most traditional method. In his bacalao al pil pil recipe, he exclusively uses an earthenware casserole, moves the casserole with wide circular motions, and never rushes the process. He prefers thick loins with skin (minimum 4 cm), adds chili as an integral part of the dish, and serves it in the same casserole. His most repeated advice: "Don't rush; if the pil pil doesn't emulsify in 10 minutes, it will in 15." Arguiñano also recommends tilting the casserole to one side to work the emulsion in the area where the oil accumulates, and gradually incorporating the rest.

Berasategui's pil pil: precision and technique

Martín Berasategui applies a more technical and controlled approach. He uses a digital thermometer to maintain the oil at exactly 60 to 65 degrees. He emulsifies the sauce in a separate bowl: he pours the gelatinous oil into a wide bowl and works it with wrist movements while adding spoonfuls of the cod's cooking broth. This allows him absolute control over the texture. Berasategui also strains the oil before emulsifying to remove solid residues, achieving a sauce with a perfectly homogeneous texture.

Quick comparison

For an easy bacalao al pil pil at home, Arguiñano's method is more accessible and more forgiving of errors. Berasategui's method requires more precision but yields a more refined result. Both are perfectly valid; choose the one that best suits your confidence level in the kitchen.

Tips for a perfect pil pil sauce

• Temperature between 55 and 70 degrees, always. This is the window in which gelatin emulsifies. Above 80 degrees, it denatures irreversibly. If you don't have a thermometer, the oil should never smoke.
• Move the entire casserole, never with a spoon. A spoon or whisk breaks the emulsion structure. Hold the casserole with both hands and make circular and back-and-forth movements.
• Dry the skin with paper and a pinch of coarse salt. Rub the skin with coarse salt and remove with kitchen paper: it extracts residual moisture that paper alone cannot.
• Add kokotxas for reinforcement. If you are using loins and the sauce is not thickening, incorporate one or two raw kokotxas directly into the oil. Their gelatin contribution unlocks the emulsion almost instantly.
• A spoonful of desalting water. The last desalting water contains dissolved albumin that acts as a co-emulsifier. Add it when you move the casserole.
• Earthenware casserole, not a thin pan. The thermal inertia of earthenware maintains a more stable temperature than metal. If you only have a pan, use one with a thick bottom and adjust the heat more frequently.
• Tilt the casserole. If there is a lot of oil, tilt it to one side and work the emulsion in the part where it accumulates. Gradually incorporate the oil from the other side.
• Do not mix types of oil. Use only one type of EVOO to maintain a constant viscosity throughout the preparation.
• Real patience. Emulsification can take 8-15 minutes. It is common for nothing to happen during the first 5-6 minutes and then for it to suddenly start. Don't give up.

How to fix a pil pil sauce that has curdled

Having the pil pil sauce curdle is frustrating but fixable. Here are the four rescue methods, from the simplest to the most drastic:

1. Remove and rest. Take the casserole off the heat, wait 2-3 minutes, and then resume stirring with gentle circular motions. Often, the emulsion simply needed to cool down.
2. Thermal contrast. Alternate 10 seconds over very low heat with 30-40 seconds off, always stirring. The temperature change reactivates the gelatin's emulsifying capacity.
3. Reconstruct in a bowl. Pour the curdled sauce into a clean bowl. Add a teaspoon of warm water to the bowl and gradually incorporate the sauce while moving your wrists, just as you would rescue a curdled mayonnaise.
4. Kokotxa reinforcement. Add a raw kokotxa to the curdled oil. Its high gelatin content provides the missing emulsifier. Cook it for 3-4 minutes and then resume stirring the casserole.

The mistake you should never make is to add flour or cornstarch. It will thicken the sauce, yes, but it will cease to be a pil pil and become something else. If, after the four methods, it still doesn't emulsify, the problem lies with the cod (probably it lacks skin or was too thin) and it's better to use it as cod in sauce.

Variations: kokotxas, prawns, chili, and black pil pil

Kokotxas al pil pil

Cod kokotxas al pil pil are the preferred version in Basque txokos. Their extraordinary gelatin content means the sauce emulsifies in half the time and with an almost creamy texture. The technique is identical to that for loin, but cooking time is reduced to 4-5 minutes per side. It is the perfect option if you are looking for an easy bacalao al pil pil with guaranteed results.

Gambas al pil pil (Prawns pil pil)

A seafood version that differs from cod pil pil in one key aspect: prawns do not release enough gelatin to emulsify. The sauce is achieved through the juice from the heads and a little more movement. It is prepared in an iron pan, with peeled prawns (reserving heads for the oil), sliced garlic, and chili. Total time: 12-15 minutes.

Pil pil with chili (traditional version)

Confitured cayenne pepper with garlic provides a subtle spiciness that contrasts with the creaminess of the sauce. It is the most widespread variant after pure pil pil: almost all Basque restaurants include it as standard. The trick is to remove the seeds from the chili so that the spiciness is mild and not aggressive.

Black pil pil (with squid ink)

An innovation of new Basque cuisine: 2-3 teaspoons of squid ink are added to the oil before emulsifying the sauce. The result is visually spectacular — a shiny black sauce — with an iodized touch that enriches the flavor without altering the emulsified texture. It works especially well with thick penca loins.

Pil pil with choricero peppers

A Navarrese variant that incorporates the hydrated flesh of 3-4 choricero peppers into the oil. The sauce acquires a reddish hue and a sweet flavor that places it somewhere between pil pil and vizcaína. It is a good entry point for those who find classic pil pil too austere.

Nutritional information and cooking times

*Daily Value based on a 2,000 kcal diet. Values are approximate and depend on serving size and amount of sauce.

Pil pil is caloric due to the olive oil, but most of its fats are monounsaturated (oleic acid), considered heart-healthy. Cod provides high-quality biological protein with almost no carbohydrates. With a light side dish -- green salad or roasted peppers -- it is a nutritionally complete meal.

Cooking times by cut

Pairing: wine, beer, and cider

Pil pil is a dish with an intense flavor and creamy texture. The ideal pairing seeks acidity and freshness to cut through the richness of the emulsified oil.

Wine

• Txakoli (Getariako Txakolina DO) -- The canonical pairing. Lightly sparkling Basque white wine, with high acidity, citrus notes, and mineral salinity. Serve very cold (6-8 degrees) and pour from a height to activate its bubbles. It is the choice of Basque txokos and cider houses.
• Albariño (Rías Baixas DO) -- Second ideal option: round structure, white peach and mineral aroma, with the necessary acidity to complement the creaminess of the pil pil without competing with its flavor.
• Godello (Valdeorras DO) -- A lesser-known but excellent alternative: more body than txakoli, floral and herbaceous notes, balanced acidity. Works especially well with kokotxas al pil pil.

Beer

• Basque or craft Pilsner -- Carbonation cleanses the palate between bites. Look for dry, hoppy pilsners, not sweet or toasted beers.

Cider

• Natural Basque cider -- Frank acidity and low alcohol content (5-6%) that contrasts with the richness of the dish. It is the pairing for cider houses, where pil pil is served as a second course after cod omelet. Pour to aerate and soften the acidity.

Avoid full-bodied red wines, very alcoholic whites, or dark beers: their potency would cancel out the nuances of the cod and compete with the sauce.

Recommended products for making pil pil at home

For a perfect pil pil, you need thick cod with skin, from cold waters, and well desalted. These are the products we recommend from our store, all with refrigerated shipping in 24-48 hours throughout Spain:

Special Pil Pil Penca (2 pcs) - 500g

13,90 EUR

Desalted Cod Kokotxas - 500g

19,90 EUR

Clean Dried Cod Fillets - 500g

21,50 EUR

"Gran Reserva Bacalao" Box

79,90 EUR

Frequently asked questions about bacalao al pil pil

Related Guides

• Cod kokotxas al pil pil: complete recipe
• Baked cod with potatoes: traditional recipe
• Cod in green sauce: the definitive Basque recipe
• Cod in sauce: green, tomato, and Vizcaína
• Recipes with desalted cod: quick ideas
• Bacalao a la vizcaína: Basque Country recipe
• Dried cod: all our cuts
• Desalted cod: ready to cook

At Bacalalo we work only with cod from Iceland and Norway, selected piece by piece so that each cut has the gelatin, thickness, and quality that pil pil demands. Refrigerated shipping throughout Spain in 24-48 hours.