How much root beer is placed in the frozen mug for a root beer float?

For a root beer float, the correct amount of root beer placed in the frozen mug is measured to be 2 inches from the rim. This specification is important because it ensures that there is enough space in the mug for the ice cream that will be added on top. The balance between the root beer and the ice cream is crucial for both aesthetic presentation and the overall consumption experience. Properly following this measurement helps achieve the desired consistency of the float, allowing for a well-blended, enjoyable treat. By allowing this space, the ice cream can float on top, creating that signature layered look of a root beer float while also preventing spillage that might occur if the mug is filled too high.