In a large bowl, mix 4 cups of flour with the baking powder, baking soda, salt, sugar and caraway seeds.
Add raisins and mix them in with fingers to make sure they are separated. Add buttermilk and mix with a fork until mixture forms a dough.
Sprinkle about 1/4 cup more flour on a board or counter, turn out dough and knead for about 5 minutes, working in the flour from the board and forming dough into a smooth, round loaf. (If humidity is high and dough is very sticky, you may need to add 1/4 cup of flour to the board.)
Grease a 9″ (1.5 L) cake pan. Press loaf evenly into pan and cut a 1/2″ (1 cm) deep cross in the top. Bake 1 1/4 hours at 350°F (180°C) or until bread sounds hollow when tapped on bottom. Remove loaf to a wire rack and cool completely before slicing.
*To substitute for 2 cups buttermilk, use 2 tbsp lemon juice plus enough milk to make 2 cups.