Combine tea, lemon, sugar and kosher salt, and simmer for 5 minutes or salt and sugar are complete dissolved. Pour in ice water and cool brine completely. Submerge thighs and drumsticks in brine for 48 hours.
Remove to a wire rack and allow chicken to drain. Combine 2 cups of the flour and the corn flour, crab boil, chili powder, salt, and pepper in a large bowl. Place remaining 1 cup flour in a medium bowl, and in a third bowl beat eggs with buttermilk. Line up bowls of flour, egg-buttermilk mixture and then the flour-corn flour mixture, in that order. Coat the chicken in the flour, then the egg-buttermilk mixture, and then the flour-corn flour mixture, applying pressure to ensure even adherence. Let the chicken sit in the refrigerator for 1/2 hour before frying.
Pour oil in a heavy pot at a depth of at least 3 inches. Heat oil to 300 degrees F. Fry chicken, submerged in oil, for 15 minutes, or until an instant-read thermometer registers 170 degrees F for dark meat, 160 degrees F for white meat. Drain on a rack. Cool to room temperature, and then place in refrigerator for at least 4 and no more than 24 hours. Serve cool from a picnic basket or cold, straight from the refrigerator.
Recipe courtesy John T. Edge, Fried Chicken: An American Story, Putnam 2004