Preheat the oven to 350ºF. Line a 12-cup muffin tin with paper liners.
Spread the wheat bran on a baking sheet and toast in the oven for six to eight minutes, stirring a few times so it cooks evenly. Let cool.
While the bran is toasting, heat 1 cup of the raisins with ½ cup of the water. Simmer for ten minutes, or until the water is all absorbed. Puree the raisins in a food processor or blender until smooth.
In a large bowl, mix together the toasted bran, buttermilk or yogurt, 1 cup water, then mix in the raisin puree, orange zest, and brown sugar. Stir in the oil, and eggs.
Mix together the flour, baking powder, baking soda, and salt, and sift directly into the wet ingredients. Stir until the ingredients are just combined, then mix in the remaining ½ cup raisins.
Spoon the batter into the muffin tins, making sure the batter is mounded slightly in each one. Because muffin tins can very in size, if your tins are larger, make fewer muffins.
Bake for 25 to 30 minutes, or until the muffins feel set in the center.