In summary: Professional technique to desalt cod in 4-6h vs the traditional 24-48h. Key trick: lukewarm water (not cold) for the first 30 min + water changes every 30 min instead of every 8h. Salt exits through accelerated osmosis. Result: perfectly desalted cod in one morning.
Table of contents
Why desaling cod normally takes 24-48h
Dry-salted cod contains 18-22% salt by weight. To reach the optimal "salt point" (1-2% final salt), 17-21% of the salt by mass must be removed. This happens by osmosis: the external fresh water attracts the internal salt.
The process depends on: (1) salinity gradient, (2) water temperature, (3) cod surface area, (4) frequency of water change.
With the traditional technique (cold water + change every 8h), equilibrium is reached slowly — 24-48h depending on thickness.
The express technique: 4-6h vs 24-48h
Step 1 (0-30 min): initial lukewarm water
Submerge cod in LUKEWARM water (not hot, ~25-28°C) for 30 min. The slightly high temperature accelerates salt diffusion by increasing the osmotic coefficient. Caution: NEVER hot water >35°C, it "cooks" the cod and hardens its texture.
Step 2 (30 min - 6h): frequent changes
Transfer to cold water (4-8°C). Change water every 30 minutes for the first 3-4 hours, then every hour for another 2 hours. Keep in the refrigerator between changes.
Step 3: check at the end
Cut a small piece from the center of the loin (the thickest part), boil for 30 seconds in water and taste. If it has the correct salt point: done. If still salty: 30 min more + 1 change.
Times according to thickness of cut
| Cut | Thickness | Express time | Traditional |
|---|---|---|---|
| Shredded | 0.5 cm | 2-3 h | 12-24 h |
| Thin slices | 1-1.5 cm | 3-4 h | 24-36 h |
| Medium loins | 2-3 cm | 4-5 h | 36-48 h |
| Thick loins | 3-4 cm | 5-6 h | 48-72 h |
Limitations: when NOT to use the express technique
The technique works well for immediate home use, but it has limitations:
- For dishes where cod is the absolute star (extra loin pil pil), the traditional 48h desalting gives a subtly superior texture.
- If the cod is very dry and old (cured >12 months), the express technique may not reach the optimal point — it needs 6-8h.
- For professionals with time, the traditional method always gives more reliable results.
Best use of express technique: emergencies, regular weekly cooking, recipes where cod goes in sauce/stew.
Frequently asked questions
Does the express technique spoil the cod?
Can I use hot water?
Changing water every 30 min vs every hour: is there a difference?
What if I bought vacuum-packed desalted cod?
Can desalted cod be re-salted if necessary?
How do I know EXACTLY if the cod is at the right point?
To conclude
The express technique is the difference between "I have to think about it 2 days in advance" and "I decide at 10 am to eat at 2 pm." If you master the times by thickness + the initial lukewarm water trick, desalting stops being a barrier to cooking cod regularly. Vacuum-packed desalted cod from Bacalalo even saves this step — it's ready to cook.
