Basically, each essential oil has a note, and that note helps determine how that oil will interact with others. These notes fall into three categories: top, middle, and base. A top note is usually the first thing you’ll notice in a fragrance. They are usually fresh and uplifting and will be the first to evaporate. Middle notes help give body and fullness to a blend. They’re often what holds the blend together and makes it work. Finally, we have the base note. It’s the foundation of your entire blend and will leave a lasting impression.