Cut the potatoes into thick matchsticks, about ½ inch wide. Try to keep them uniform so they cook evenly. Place them in a pot with cold water, adding a splash of vinegar and salt.
Why start cold: This helps the potatoes cook evenly from the inside out and prevents the outer layer from over-softening. The vinegar helps strengthen the potato’s structure, so your fries stay crisp after frying.
Bring to a gentle boil and cook for 5–7 minutes, until just tender but not falling apart. Drain carefully and lay on a wire rack to dry.
Place the rack in the freezer for 1 hour (or fridge for 2 hours) to remove surface moisture.
Tip: Drying the potatoes thoroughly before frying prevents oil splatter and ensures maximum crispiness.

In a small bowl, combine mayonnaise, capers, pickles, Dijon mustard, lemon juice, parsley, salt, and pepper. Mix until smooth.
Tip: Let the tartar sauce chill in the fridge while you cook — the flavors will meld and intensify.

Cut the fish into 4–5 inch pieces. Pat dry with paper towels and season lightly with salt and pepper.
Why cod: Cod’s firm, flaky texture and mild flavor make it perfect for frying — it stays juicy inside while the crust crisps beautifully. Haddock, pollock, or halibut are great alternatives.

Dust each piece lightly in flour and shake off the excess.
Why flour first: The flour creates a dry surface that helps the batter adhere evenly, ensuring the crust stays intact during frying.

In a large bowl, whisk together flour, cornstarch, baking powder, salt, and paprika.
Why cornstarch and baking powder: Cornstarch creates a delicate crunch, while baking powder helps aerate the batter, making it light and crisp instead of doughy.

Gradually pour in the cold beer, whisking until smooth and thick — about pancake batter consistency.
Why cold beer matters: Cold beer releases carbon dioxide when it hits hot oil, forming tiny air bubbles that puff up the batter and create a light, shatter-crisp coating. Warm beer would lose this effect.
Add a few ice cubes to keep the batter cold while frying.

Heat oil in a deep pot to 325°F (165°C). Fry the potatoes in small batches for 3–4 minutes — they should be pale and soft, not golden yet. Remove and drain on a rack.
Tip: Don’t overcrowd the pot — too many fries lower the oil temperature and make them greasy.

Increase the oil temperature to 350°F (175°C). Dip the fish in the batter, let the excess drip off, and gently lower into the oil. Fry for 7–10 minutes, until golden and crisp.
Remove to a paper towel-lined plate or rack to drain excess oil.
Tip: Keep the oil hot and consistent; if the temperature drops, the batter will absorb more oil and turn soggy.

Raise the oil temperature to 375°F (190°C). Return the pre-fried potatoes and cook again for 5–7 minutes, or until deep golden and crisp. Remove and season immediately with flaky sea salt.
Tip: The double-fry method ensures a creamy interior with an ultra-crisp exterior — the hallmark of perfect chips.

Arrange the fish and chips on a serving plate with tartar sauce on the side.