Place 4 cups of the buttermilk (leave the remaining 2 cups to one side) together with the sugar, garlic and a good pinch or 2 of salt in a glass bowl and whisk together well.
Add chicken and toss to make sure all of the chicken is coated.
Cover with clingfilm and refrigerate 1 hour.
In another bowl, pour the flour, cayenne, 1 tsp of salt, 1 tbsp of pepper and mix thoroughly.
Pre heat you deep fat fryer to 325`F
Place the buttermilk mixture, the flour mixture and the the remaining buttermilk into a third bowl.
Only do the quantity your dryer can handle in one go. Don't overload.
Take the chicken pieces out of the buttermilk mixture letting any excess drip off, coat each peiece with the flour mix and then into the buttermilk bowl. Finally coat the chicken back n the flour mix and shake off excess flour.
Now you see why a piece a a time is best. This piece in now ready for the fryer.
Add the chicken to the oil and fry until golden brown and thoroughly cooked. Normally 5 to 10 minutes
Keep on repeating the procedure until all of the chicken is cooked.