1. Make the Pre-coating: In a large bowl whisk together the first 4 ingredients. Add the chicken and toss well until evenly coated in all areas. Transfer chicken to a rack, shaking the chicken well to get rid of any excess coating. Let rest uncovered for one hour.
2. Pour enough oil into a 6-quart Dutch oven to reach a depth of 2 inches. Heat oil over medium-high heat until a deep fry thermometer reads 175°C.
3. Make the Batter: In a large bowl whisk together dry ingredients. In a smaller bowl, whisk together the wet ingredients. Just before frying, whisk the wet mixture into the dry mixture. The consistency should be relatively thin and runny.
4. Working in two batches, dip each piece of chicken into the batter, letting excess batter drip off. Suspend the chicken in the oil for a couple of seconds for it to set before letting it slip completely into the oil, otherwise the chicken will fall and stick to the bottom of the pot.
5. Fry chicken until golden brown and cooked through, 15 to 20 minutes per batch. Transfer to a wire rack to drain as done.
6. Make the BBQ Sauce: Combine all of the ingredients in a small saucepan and simmer over medium heat until slightly thickened, 3 to 5 minutes.
7. Serve the chicken with the BBQ sauce, pickled radish and beer.