For the batter
200g plain flour
1 tsp fine sea salt
330ml real ale
2 tbsp white wine vinegar
For the fish
6 tbsp plain flour
½ tsp fine sea salt
4 x 200g pollack fillets
Heat the oil in an electric deep fat fryer to 180C
For the batter, mix the cornflour, plain flour and salt together in a large bowl. Make a well in the centre of the mixture and whisk in the ale and vinegar. Beat with a large metal whisk to make a smooth batter with the consistency of double cream.
Mix the flour and salt onto a large plate
Coat a fillet in the seasoned flour and dip into the batter until thoroughly coated. Gently lower the fish into the hot oil.
Repeat the process with a second fish fillet and cook with the first for 5-6 minutes (depending on the thickness of the fillets) or until golden-brown and crisp. It's important that the batter doesn't brown too quickly before the fish is cooked. Remove the fish and transfer to a plate lined with kitchen paper to absorb any excess oil.
Reheat the oil and cook the remaining two pieces of fish in exactly the same way.
Serve with freshly cooked chips and tartare sauce.