Bacalao (salt cod) — the preserved fish that sustained Catholic Spain through centuries of meatless days — requires careful desalting before use. The desalting is not simply a removal of excess salt but a rehydration and partial reconstitution of the dried cod's compressed proteins. A correctly desalted bacalao should taste mildly seasoned, should be fully hydrated, and should have the firm-but-yielding texture of fresh fish. Under-desalted bacalao is inedibly salty; over-desalted becomes bland and waterlogged.
- **The desalting:** 24–48 hours in cold water — changing the water 3–4 times per day. [VERIFY] Koehler's desalting specification. - **The cold water requirement:** Warm water draws out salt but also begins to cook the fish proteins and produces a different (undesirable) texture. Cold water desalts slowly and completely. - **Desalting test:** Taste a small piece after 24 hours. If still aggressively salty, continue. Target: pleasantly seasoned. - **Brandada de bacalao (salt cod brandade):** The classic preparation — desalted cod poached in milk, then whipped with olive oil and cream into a smooth, rich paste. The emulsification of cod proteins with olive oil is identical in mechanism to aioli. - **Bacalao al pil pil (Basque):** Desalted cod cooked in olive oil at very low temperature. The gelatin from the cod's skin and the proteins released by the gentle cooking emulsify with the olive oil into a thick, white, naturally occurring sauce. The pil pil sauce (CRM Family 09 — protein network formation) forms through agitation of the pan — circular swirling causes the released proteins to emulsify with the oil.
Spain: The Cookbook