I tried using the peel of two oranges during the last 5 minutes of the boil (4.5 gallons) for a three gallon batch of IPA with the intent of adding aroma and flavor. Before adding to the boil, I filleted the pith off the peel. I couldn’t tell that it added anything to the final product. However, I’ve only done this twice, so I’m not sure I’ve nailed the process.