Here's why:

* pH Scale: The pH scale measures how acidic or basic a substance is. A pH of 7 is neutral, below 7 is acidic, and above 7 is basic.

* Malic Acid: Apples contain a significant amount of malic acid, which gives them their tart flavor.

* Measurement: Apple juice typically has a pH between 2.9 and 3.3, which is definitely on the acidic side of the scale.

So, while it's delicious, apple juice is definitely an acidic beverage.