How do you make Peruvian ceviche, and how does the acid 'cook' the fish?

Question

How do you make Peruvian ceviche? Understand how the acid from citrus juice effectively 'cooks' the raw fish.

Answer 1

Peruvian ceviche is made by marinating fresh raw fish in citrus juices, typically lime, with ají peppers, onions, and cilantro. The citric acid denatures the proteins in the fish, causing it to firm up and appear 'cooked' without heat.

Detailed Explanation:

Here's a step-by-step guide to making authentic Peruvian ceviche:

1. Choose the freshest fish: Select a firm, white fish like corvina, sea bass, or flounder. The fresher the fish, the better the ceviche. Look for fish that smells fresh and doesn't have a strong odor.
2. Prepare the ingredients: You'll need fresh limes (key limes are ideal), red onion thinly sliced, ají amarillo or other chili peppers (seeded and minced), fresh cilantro chopped, and salt and pepper to taste.
3. Cut the fish: Cut the fish into bite-sized cubes, about 1/2 inch in size. This allows the lime juice to penetrate evenly.
4. Marinate the fish: Place the fish in a non-reactive bowl (glass or stainless steel). Add the lime juice, salt, and ají peppers. Gently mix to ensure all the fish is coated.
5. Let it 'cook': Allow the fish to marinate in the lime juice for 10-15 minutes. You'll notice the fish will change color and become opaque, similar to cooked fish. This is the citric acid denaturing the proteins.
6. Add the finishing touches: Gently mix in the red onion and cilantro. Taste and adjust seasoning as needed.
7. Serve immediately: Ceviche is best served immediately. Traditionally, it's served with sweet potato, corn on the cob (choclo), and cancha (toasted corn kernels). The leftover marinade, called 'leche de tigre' (tiger's milk), is often drunk as an aphrodisiac and hangover cure.

The 'cooking' process in ceviche is actually a chemical reaction. The citric acid in the lime juice denatures the proteins in the fish. Protein denaturation causes the protein molecules to unfold and tangle, changing the texture and appearance of the fish. This process mimics the effects of heat, making the fish firmer and opaque, but it doesn't involve actual cooking with heat.

Pro Tip:

Don't over-marinate the fish! Leaving it in the lime juice for too long will result in a rubbery texture. Aim for the 10-15 minute window for optimal results.