Once you have acquired the Nimbus 2000, you can take it for a test run on Hogwarts Ground. Simply equip it and press the button to hop on it. The flying controls are the same, but you get to freely explore Hogwarts and its vast fields. Floating high in the air above and around the school are a few rings, which you can fly through. Flying through them helps you amass a great number of Bertie Bott's Beans.

They relocate every time you head through them. The rings vary in color. Different colors mean a different amount of beans will be given. As a side note, you can't dismount the broomstick unless you land at the Hogwarts front entrance, or in front of the Quidditch Stadium. Just press the button again and Harry will dismount.

Another way to find beans is to blast every tangible object with Flipendo. Most objects will cough up at least three beans. When you return to them a later time, they sometimes will give up more! Objects like masks, vases, jugs, boxes, etc. should all have some beans to share.