Saira has potions on Monday and Thursday. She paid intensely careful attention to Mr. Elmasry's directions, took meticulous notes, and brewed a note-perfect potion because that is how she rolls. However she was not so much into discussing what hers smelled like because that feels very private.
That being said, to her it smells of honey, melon, paper and ink, and soap.
Scents associated with her might be attar of roses, curry spices, ink...does studying have a scent? Because that.