Summary: Properly desalting cod is the step that determines whether a dish turns out well or is ruined. This guide explains the four methods with exact times — 30 minutes for emergencies, 2 hours for fillets, 4 hours for medium loins, and 24-48 hours for optimal results —, a complete table by cut and thickness, 10 mistakes with their solutions, and how to know for sure if the salt level is correct before cooking. Written by the Bacalalo team, since 1990 at the Mercat del Ninot in Barcelona.
Table of Contents
- Desalting Cod: The Basics You Need to Know Before Starting
- Quick Method: Desalting Cod in 30 Minutes (for Emergencies)
- Standard Method: Desalting in 2-4 Hours (Most Commonly Used)
- Traditional Method: Desalting in 24-48 Hours (Highest Quality)
- Complete Table of Desalting Times by Cut and Thickness
- 10 Desalting Cod Mistakes and How to Avoid Them
- How to Know if Cod is Properly Desalted (The Bite Test)
- Storing Desalted Cod (Refrigerator vs. Freezing)
- Desalting Cod for Pil Pil: Why Desalting Matters More Here
- Frequently Asked Questions
Salted cod is one of the great products of Spanish cuisine. We use it in pil pil, vizcaína, esqueixada, fritters, ajoarriero, brandada. But all those dishes depend on a step that most people do wrong, do too quickly, or do without understanding why: desalting.
Poorly desalted cod ruins any recipe, no matter how expensive the piece. Perfectly desalted cod turns a simple dish into something memorable. At Bacalalo, we have been working exclusively with quality cod at the Mercat del Ninot in Barcelona for over 35 years, and the question we still get asked most frequently every day is the same: how to desalt it properly, how long it takes, and why most people do it wrong.
This guide answers all of that. No beating around the bush.
Desalting Cod: The Basics You Need to Know Before Starting
Updated March 2026. After decades of working with seafood, we have learned that quality makes all the difference.
Before discussing methods and times, it's helpful to understand what is physically happening when you desalt cod. This is not useless theory — understanding it will help you avoid mistakes.
Why cod contains so much salt
Salted cod has undergone a curing process that can last from 3 weeks to several months. Salt penetrates deeply into the muscle fibers of the fish through osmosis, extracting most of the water. The result is a piece that can have a salt concentration of between 18% and 22% of its weight. For reference, seawater has a salinity of 3.5%. Dried cod is literally five to six times saltier than the sea.
It cannot be eaten without desalting. It's not a matter of taste — it's inedible and indigestible.
How desalting works (osmosis)
Desalting works by osmosis: when you submerge the cod in fresh water, the concentration difference between the flesh (highly salted) and the water in the container (unsalted) causes the salt to migrate from the cod into the water to balance both concentrations. At the same time, the fish absorbs clean water and rehydrates.
The goal is not to remove all the salt — that would ruin the flavor. The goal is to reach a residual concentration of between 1% and 2%, similar to that of a well-seasoned dish. At that point, the salt is present, enhances the fish's flavor, but does not dominate.
What you need before you start
- A large container — the cod should be completely covered in water, with at least 3-4 cm above it. A small container saturates the water with salt too quickly and slows down the process.
- A rack at the bottom — if you elevate the cod from the bottom of the container (with a rack, a colander, or even some chopsticks), the salt that it releases falls by gravity and does not come back into contact with the fish. This is the system we use in the fish market and it makes a real difference.
- Cold water — always cold. In summer, if the tap water is lukewarm, add ice cubes. The ideal temperature is between 4°C and 8°C.
- Refrigerator with space — desalting should always be done in the refrigerator. At room temperature, the process is faster, but the bacterial risk with a piece of protein in water for hours is real. It's not worth it.
- Initial rinse — before submerging, run each piece under the tap for 30-60 seconds, gently rubbing to remove superficial salt crystals. This first wash removes the most concentrated layer of salt and speeds up the entire subsequent process.
Professional tip: if you have pieces of different thicknesses, desalt them in separate containers. Thick loins take twice as long as flakes. If you mix them, by the time the flakes are perfect, the loins will still be salty, and if you wait for the loins to be good, the flakes will have lost all their salt and will be bland.
Quick Method: Desalting Cod in 30 Minutes (for Emergencies)
This method is for when there is no time. It applies exclusively to cod flakes, shredded cod, and very small pieces (less than 1 cm thick). For loins or fillets, this method does not work — the salt from the inside does not have time to come out.
Expected result: acceptable for recipes where the cod is mixed with other ingredients (croquettes, fritters, brandada, salads). Not recommended for dishes where the loin is the main ingredient.
Steps to desalt in 30 minutes
- Rinse under the tap for 3-4 minutes — rub the cod with your fingers to remove all visible salt and the surface layer. This initial step is more important the less time you have.
- Cover with lukewarm water (between 30°C and 35°C, no more) — slightly warm water accelerates osmosis because molecules move faster. Never use hot water: it would cook the outside of the cod and close the pores that need to open to release salt.
- Let it rest for 15 minutes, stirring gently every 5 minutes.
- Change the water — rinse again and submerge in cold water for another 10-15 minutes.
- Test the salt level — take a small piece from the thickest part and taste it raw. If it is tolerable for your recipe, it is ready.
Important limitation: in 30 minutes, only the outer layer is desalted. The inside of medium or large pieces will still be salty. This method is only valid for flakes and thin pieces where the distance from the surface to the center is minimal. If your piece is more than 1 cm thick, do not use this method — the result will be cod that is salty on the inside and correct on the outside, which will ruin it when cooked.
For already desalted cod that you want to buy without complications, check out our selection of desalted cod loins — ready to cook directly.
Standard Method: Desalting in 2-4 Hours (Most Commonly Used)
This is the reference method for most household situations. It works well with thin fillets, slices, and medium loins cut into portions (1 to 2 cm thick). It is not the highest quality method, but it is the most balanced between time and result.
Expected result: very good for fillets and medium portions. The inside of the loin may be slightly saltier than the surface, but if the steps are followed correctly, the result is more than acceptable for most recipes.
Steps to desalt in 2-4 hours
- Rinse each piece thoroughly under the tap for 60 seconds, rubbing with your fingers.
- If the pieces are thick, cut them in half or into portions — reducing the thickness by half reduces the desalting time by a quarter (osmosis works on all cut surfaces simultaneously).
- Place in the container with the skin facing up — the skin is a partial barrier that slows the salt from coming out on that side. If you put the skin down, the flesh side desalinates quickly but the skin side retains too much salt.
- Cover completely with cold water and place in the refrigerator.
- Change the water every 45-60 minutes — in this accelerated method, frequent changes are key. With each change, fresh water reestablishes the osmotic gradient that gradually balances with the salt coming out of the cod.
- After 2 hours, taste a piece from the thickest part. If the salt level is correct for your recipe, remove. If it is still salty, continue for up to 4 hours.
For which recipes this method works:
- Grilled or pan-seared cod (thin fillets)
- Baked cod with vegetables
- Cod Vizcaina or Riojana style (medium portions)
- Cod with tomato or chickpeas
- Esqueixada (in this case use shredded cod, which only needs 1-2 hours)
For which recipes it is NOT enough: pil pil with whole loin, traditional cod pil pil with a piece more than 3 cm thick. For these preparations, use the 24-48 hour method.
Cod that does not require desalting: if you prefer to skip all this, our desalted cod loins are ready to cook directly. They go through the desalting process at our facility in Mercat del Ninot, with precise salt level control. For everyday use, it is the most practical option. For special recipes with whole dried cod loin, desalting at home gives more control over the final result.
Traditional Method: Desalting in 24-48 Hours (Highest Quality)
This is the correct method. There are no shortcuts when quality matters. If you are preparing bacalao al pil pil, a celebratory vizcaína, or any dish where the whole loin is the star, this is the only method that guarantees a homogeneous result from the inside out.
Why 24-48 hours: salt is not just on the surface of the cod — it is deeply distributed throughout the muscle. For osmosis to reach the center of a loin 3-4 cm thick, it needs time. There is no way to speed up physics without compromising texture. A loin desalted in 4 hours will have a perfect exterior and a still-salty interior; when cooked, that interior salt will migrate to the exterior, and the dish will be unbalanced.
Steps for the traditional method (24-48 hours)
- The day before (D-1 or D-2), rinse the pieces under the tap for 60-90 seconds. Rub well to remove all visible salt crystals on the surface and in the skin folds.
- Place the pieces in the container with the skin facing up. If you have a kitchen rack or a colander that fits in the bottom of the container, use it to elevate the cod: the salt falls to the bottom by gravity and does not come back into contact with the fish.
- Cover completely with cold water — the water level should be at least 3-4 cm above the cod. Too little water is the most common mistake and the one that unnecessarily lengthens the process the most.
- Place in the refrigerator, covered or wrapped with plastic film to prevent the cod from absorbing odors from other foods.
- Change the water every 8 hours — for medium loins (2-3 cm), make 3 changes in 24 hours. For thick loins (more than 3 cm), make 4-6 changes in 36-48 hours. With each change, briefly rinse the pieces before re-submerging them.
- After 24 hours, do the bite test (see dedicated section below). For very thick loins, you will likely need between 36 and 48 hours.
- When the point is correct, remove the cod from the water, dry thoroughly with paper towels, and cook immediately. If not cooking right away, store in the refrigerator on absorbent paper and use within the next 24-48 hours.
This method is what professional chefs use and what we have been teaching at Mercat del Ninot since 1990. The difference in the final result compared to accelerated methods is remarkable: the texture is more uniform, the salt point is more precise, and the gelatin of the cod is not altered.
For the dry cod most suitable for the traditional method, check out our selection of dry cod — we work exclusively with Gadus morhua from Iceland and Norway.
Complete Table of Desalting Times by Cut and Thickness
This table shows reference times for correct desalting in the refrigerator (between 4°C and 8°C) with regular water changes. Times are approximate: always confirm with the bite test before cooking.
| Cod Cut | Thickness | Minimum Time | Optimal Time | Water Changes |
|---|---|---|---|---|
| Flakes and shredded cod | Less than 1 cm | 30 min | 2-4 hours | Every 30-45 min |
| Esqueixada (shredded cod) | Less than 1 cm | 1 hour | 2-3 hours | Every 30 min |
| Thin fillets and slices | 1-1.5 cm | 4 hours | 8-12 hours | Every hour |
| Cheeks (kokotxas) | 1-2 cm | 6 hours | 12-18 hours | Every 6-8 h |
| Medium loins (portions) | 2-3 cm | 12 hours | 24-36 hours | Every 8 h |
| Thick whole loins | 3-5 cm | 24 hours | 36-48 hours | Every 6-8 h |
| Very thick pieces / snouts | More than 5 cm | 36 hours | 48-72 hours | Every 6-8 h |
| Dried cod (stockfish) | Variable | 3 days | 4-7 days | Every 12 h |
How to read this table: The minimum time is the absolute minimum for the process to be effective — the result may still be somewhat salty. The optimal time guarantees a consistent result. If in doubt, always opt for the optimal time and confirm with the bite test.
For a more detailed view of this table, including variations by curing type and water temperature, consult our desalting times by thickness guide.
Variables that modify the times
The times in the table are for cod with standard curing. These factors can lengthen or shorten the process:
- Very long curing (cod more than 6 months in salt): add 25-30% to the optimal time.
- High water temperature (above 10 °C): shortens the time but increases bacterial risk. Always keep below 8 °C.
- Container with little water: the water saturates with salt quickly and the process slows down. Always use plenty of water.
- Piece cut into portions vs. whole piece: cutting a 4 cm loin into 2 cm portions reduces desalting time by approximately half.
10 mistakes when desalting cod and how to avoid them
These are the most frequent mistakes we see at Mercat del Ninot, which lead customers back to ask us what went wrong.
Mistake 1: desalting at room temperature
Cod in water at room temperature (15-22 °C) is an ideal breeding ground for bacteria. Desalting can take hours or days — all that time in warm water outside the refrigerator is a real risk of food poisoning. Solution: always in the refrigerator, always below 8 °C.
Mistake 2: not changing the water (or changing it too few times)
The water saturates with salt as the process progresses. Once the osmotic gradient balances, desalting stops — the cod can spend hours in the same salty water without losing additional salt. Solution: change the water according to the frequency indicated in the table. In accelerated methods, every 45-60 minutes; in the traditional method, every 6-8 hours.
Mistake 3: using too little water
If the container is small and the water is scarce, the water saturates with salt quickly. It's the same problem as not changing the water, but more immediate. Solution: use a large container. The cod should be submerged with at least 3-4 cm of water above it and free space on the sides.
Mistake 4: mixing pieces of different thickness
If you desalt a thick loin and some flakes together in the same container, when the flakes are perfect the loin will still be salty, and if you wait for the loin, the flakes will have lost too much salt. Solution: separate containers for each cut or thickness. This is the system we use in the fishmonger's.
Mistake 5: placing the skin face down
The skin acts as a partial barrier that slows salt migration. If you place it face down, the flesh side desalts quickly but the skin area retains salt, resulting in an uneven outcome. Solution: always place the pieces with the skin facing up.
Mistake 6: not rinsing before submerging
The surface layer of salt is the most concentrated. If left, it slows the start of the process and can quickly saturate the first water bath. Solution: always pre-rinse under the tap for 30-60 seconds, gently rubbing, before the first soak.
Mistake 7: desalting with hot water for too long
Warm water accelerates osmosis, but if the cod spends more than 30-45 minutes in water above 35 °C, the surface proteins begin to coagulate. The texture becomes rubbery and irreversible. Solution: if you use warm water as an accelerated start, only for the first 15-20 minutes, never above 35 °C, and quickly transfer to cold water in the refrigerator.
Mistake 8: not tasting for doneness before cooking
The times are approximate. Cod that has been cured for more months will need more time than freshly cured cod. The only way to know if it's ready is to taste it. Solution: always do the bite test before cooking (see next section).
Mistake 9: leaving the cod in water for too long (over-desalting)
Over-desalting is a less frequent but possible mistake. Cod that has been in water for 72 hours with frequent changes can become completely tasteless. It loses not only salt but also part of its own flavor. Solution: do not exceed the optimal times in the table and taste regularly starting from the minimum time.
Mistake 10: not drying the cod before cooking
After desalting, cod has a lot of surface water. If you put it directly into the pan, the water causes splattering, lowers the oil temperature, and the cod boils instead of browning. Solution: after desalting, always dry each piece with kitchen paper, gently pressing. For pil pil, this step is especially important.
For a more detailed analysis of each error and its solutions, consult our complete guide on errors when desalting cod.
How to tell if the cod is properly desalted (the bite test)
The times in the table are starting points, not guarantees. The only valid test is the organoleptic test — in simple terms: tasting it.
The bite test: step-by-step
- Remove the cod from the water and lightly dry it with kitchen paper.
- Cut a small piece from the thickest part — the center of the loin is where it takes longest to desalt, so it's the control point.
- Taste the raw piece, chewing well so that saliva activates the perception of salt.
- Evaluate the result:
| What you perceive when tasting | What it means | What to do |
|---|---|---|
| Aggressive saltiness, almost like eating salt alone | Insufficient desalting | Continue for at least 4-6 more hours with water changes |
| Noticeable but tolerable saltiness, like a slightly over-salted dish | Almost ready, but a little more needed | Continue for 2-3 more hours; may be fine if the recipe includes balancing sauces |
| Salt present but balanced, like a well-seasoned dish | Perfect point | Remove, dry, and cook |
| Practically tasteless, like eating unsalted white fish | Over-desalted | Add salt when cooking; no retroactive solution |
Important nuance: the ideal salt level also depends on the recipe. For pil pil, the cod must be at its exact point because the sauce has no added salt and the cod is practically the only salt contribution to the dish. For a vizcaína or a tomato sofrito, you can tolerate a slightly saltier level because the other ingredients balance it out. For esqueixada (which is eaten raw), the cod must be perfectly desalted without excesses or defects.
The water drop test: there is another complementary test for large pieces. Place a small drop of water on the surface of the cod and bring it to your lips. If you perceive noticeable salt, the exterior is still salty. If you perceive it as mild or minimal, the exterior is fine — but that tells you nothing about the interior, which is why the bite test by cutting the center is the definitive one.
Storing desalted cod (refrigerator vs. freezing)
Once desalted, cod is a perishable product. It has lost the protection provided by salt and has a high water content. From the moment you finish desalting, the clock starts ticking.
In the refrigerator
Desalted cod can be stored safely for 24 to 48 hours in the refrigerator. Longer is possible, but quality decreases and the risk of spoilage increases.
To store it correctly:
- Dry it well with kitchen paper — surface moisture accelerates spoilage.
- Place it on absorbent paper in a covered container.
- Store it in the coldest part of the refrigerator (bottom section, away from the door).
- If more than 24 hours pass and you haven't cooked it, smell it before using: spoiled cod has an unmistakable acidic or ammoniacal odor.
In the freezer
If you are not going to cook the cod within the next 48 hours, the best option is to freeze it immediately after desalting. Desalted cod can be frozen with good results if done correctly:
- Dry it very well — surface moisture creates large ice crystals that damage the texture when thawed.
- Freeze in individual portions, wrapped in film or in freezer bags with the air removed.
- Label with the date — it can be stored for up to 3 months in the freezer with acceptable quality. Longer than that, the texture suffers.
- Always thaw in the refrigerator, never at room temperature or in hot water.
For a detailed guide on freezing and thawing, consult whether to freeze desalted cod and how to store desalted cod at home.
Difference between dried cod and desalted cod at the starting point
If you're wondering whether it's better to buy dried cod and desalt it at home or buy already desalted cod, the answer depends on the use. For a complete analysis, consult our guide on dried cod vs. desalted cod: which to buy for each recipe.
In summary: dried cod offers more control over desalting and is more economical per kilo of finished product, but requires planning. Already desalted cod is more practical and reliable for everyday use, but has a shorter shelf life. At Bacalalo, we have both options: our selection of dried cod and our selection of already desalted cod.
Desalting cod for pil pil: why desalting matters more here
Cod pil pil is the recipe where desalting has the most impact on the final result. More than in any other preparation. That's why it deserves its own section.
Why pil pil is different
In most cod recipes, the fish's salt competes with other ingredients: sofrito, sauce, vegetables, spices. A slightly over-salted cod can be compensated for by the recipe. In pil pil, there is no such margin: the dish is oil, garlic, chili, and cod. The cod is the only salty contribution to the dish, and the gelatin it releases is the base of the sauce. There is nothing to disguise it.
If the cod is too salty, the pil pil will be excessively salty with no possibility of correction. If it is over-desalted, the dish will be bland and the sauce will lose character.
Which piece to choose for pil pil and how to desalt it
For pil pil, the ideal piece is the center cod loin, with skin, between 3 and 5 cm thick. This cut has the highest proportion of collagen in the skin, which, when cooked slowly at a low temperature, turns into gelatin and emulsifies with the oil to form the characteristic sauce.
To properly desalt that loin for pil pil:
- Use the traditional 36-48 hour method — there's no shortcut here.
- Change the water every 8 hours: at least 4-5 changes for a 4 cm loin.
- In the last water change (the last 8 hours), do not add salt to the water — the goal is to reach the exact point of residual salt, not to over-desalt.
- Do the bite test with the thickest piece from the center of the loin: a subtle saltiness should be perceived, present but not dominant.
- Dry very well with kitchen paper before cooking — surface moisture interferes with the emulsification of gelatin in the oil.
For more detail on the ideal piece and the specific process for pil pil, consult our complete guide on which cod piece to choose for pil pil.
The role of gelatin in desalting
A point that most people overlook: desalting also affects the cod's gelatin, not just the salt. If you desalt with very hot water or change the water too aggressively, part of the cod's surface gelatin is lost in the water. In a normal recipe, this has minor impact. In pil pil, that gelatin is literally the sauce. That's why the traditional method always uses cold water and gentle changes, without excessive rubbing or hot water.
For a benchmark pil pil, use our traditional dried cod sheet — the complete cut of cod with skin, with the loin and the most gelatinous areas intact. It is the benchmark piece for classic Basque pil pil.
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Frequently Asked Questions
How long does cod need to be desalted?
It depends on the thickness of the piece. Flakes need 2-4 hours. Thin fillets, 4-12 hours. Medium loins (2-3 cm), 24-36 hours. Thick loins (more than 3 cm), 36-48 hours. Always in the refrigerator and with regular water changes. The bite test is the only definitive confirmation.
Can cod be desalted in 1 hour?
In 1 hour, only the outer layer of the cod can be desalted. For flakes less than 1 cm thick, 1-2 hours with frequent water changes may be sufficient. For any piece thicker than 1 cm, 1 hour is not enough: the inside will still be very salty. The result will depend on the recipe, but for loins or fillets, 1 hour is insufficient.
Can cod be desalted without refrigeration?
It is not recommended. At room temperature (above 15 °C), the risk of bacterial proliferation in the soaking water is real after a few hours. If the ambient temperature is below 10 °C (winter in a cold area), it could be done carefully, but the refrigerator is always the safe option.
What happens if the cod is too salty after cooking?
If it's already cooked and too salty, options are limited. If the recipe includes a sauce, you can add more liquid (water, unsalted broth, milk) to dilute the salt concentration in the dish. If it's a grilled loin, there's no retroactive solution. The only prevention is to do a taste test before cooking.
Can desalted water be reused?
No, never. The desalted water is full of salt, and that's precisely what you want to separate from the cod. Reusing that water would be counterproductive—you would saturate the process and the cod would not lose any more salt.
Can desalted cod be re-salted for preservation?
This process does not yield good results at home. Artisan salt cod undergoes controlled curing processes that are not reproducible with kitchen salt at home. Once desalted, cod should be consumed within 24-48 hours or frozen. Home re-salting does not guarantee preservation.
Does milk desalt faster than water?
No. Milk does not desalt faster than water – the osmotic process works the same. What milk does is soften the final flavor: casein proteins and milk fat tone down residual saltiness and provide a slight sweetness. It's used as a final step in desalting (replacing the last water change), not as a method in itself. For intensely cured cod or creamy recipes (brandade, croquettes), it can be an interesting touch.
How do I know if the cod is perfectly salted without tasting it?
There is no completely reliable way without tasting it. The color of the water (cloudier and yellower at the beginning, clearer at the end) can be a visual indicator, but it's not definitive. The texture (the cod progressively softens as it rehydrates) also provides clues. But the only definitive test is the bite test: cut a piece from the center of the thickest piece and taste it raw.
Can frozen cod be desalted directly?
Frozen dried salted cod should first be thawed in the refrigerator (24-48 hours) before desalting. Desalting frozen cod makes it difficult for water to penetrate the muscle, and the results are inconsistent. Thaw first, then desalt.
What is the difference between commercially desalted cod and homemade desalted cod?
Commercially desalted cod goes through a controlled process with exact timings, regulated temperature, and salt point control through concentration measurement. The result is consistent across pieces. At home, the process is more variable—the result depends on the exact thickness of the piece, the refrigerator temperature, and the cook's attention. For daily use, the already desalted cod you'll find in our selection of desalted cod is more practical. For special recipes where you want to control the exact result, doing it at home with quality dried cod gives more control.
At Bacalalo, we have been in the Mercat del Ninot in Barcelona for over 35 years—since 1990—working with quality cod. Desalting is not a minor detail: it is the step that determines the quality of the dish. A good cod poorly desalted is ruined. A standard cod well desalted can surprise. Give it the time it deserves.
To explore the cod options we work with, visit our selection of dried cod—for desalting at home and controlling the process—and our selection of already desalted cod—for cooking directly without waiting.
