Makes 18 cups
Preheat oven to 250°F.
Coarsely chop almonds, walnuts, and pecans into either by hand or in a food processor. In a large bowl or pot, mix chopped nuts with sunflower seeds, sesame seeds, oat flakes, bran, dry milk, cinnamon, and nutmeg. Stir together thoroughly and set dry granola base mixture aside.
Meanwhile, combine oil, honey and orange flavor in a small pot. Over low heat, gently heat the mixture just until it looks like syrup. (Do not boil.)
Mix honey mixture with dry granola base mixture and mix thoroughly, making sure that all the dry ingredients are coated with the honey mixture.
Spread granola over two large jelly roll pan or cookie sheets (approximately 17 inches X 14 inches) and place into the preheated oven.
Total baking time will be 60 minutes. To prevent burning, stir the granola mixture every 5 minutes, especially on the edges. (Note: for more even baking of granola, try switching the jelly roll pans to opposite racks after the first 30 minutes.)
Add coconut flakes and raisins during the last 10 minutes of baking, dividing them between the granola mixture on the two cookie sheets. After adding the coconut and raisins complete the final baking process, baking another 10 minutes, including stirring mixture midway. Granola is done when it looks golden brown. Bake up to an additional 5 minutes if it needs a bit more toasting.
Remove cookie sheets from the oven, placing them on wire racks to cool. In order to ensure granola retains a chunky texture, allow granola to cool thoroughly on the cookies sheets before stirring. Store granola in the refrigerator within a moisture-proof container.