In a large mixing bowl, add warm water and yeast. Cover and let activate for 10 minutes.
Add bread flour, canola oil, Agave, salt and 4 cups of whole wheat flour to the yeast mixture. Mix thoroughly.
Mix in sunflower seeds. Slowly add whole wheat flour one cup at a time until you reach a firm dough.
Turn dough onto a floured surface and knead for 5-8 minutes until smooth and elastic. Place in a greased bowl, turning once to grease the top. Cover and let rise in a lightly warmed oven for 1 hour or until doubled in size (hint: Before I place the bread in the oven, I turn the oven on to 350F degrees and warm it for only a few seconds--20-seconds. You don't want the oven hot).
Punch down the dough and divide into either two greased 9 x 5-inch loaf pans, or three greased 8 x 4-inch loaf pans. I like to put parchment on the very bottom of my pans for ease of turning out the loaves. Cover the loaves and let rise in a warm place for an additional 30 mins or until doubled in size.
Bake at 350F degrees for 35 minutes, then brush on melted butter and continue to bake for 5 minutes more or until lightly browned.
Remove from oven and brush on remaining melted butter. Turn out from pans and place on a wire rack to cool completely before cutting and serving.