Acidity is a measure of how much acid is present in a substance, and it's usually expressed as a pH level. You might remember learning about pH levels in school, with acidic substances having a low pH and basic substances having a high pH. For example, lemon juice is very acidic, with a pH of around 2, while baking soda is very basic, with a pH of around 8.
Now, back to vanilla extract: its pH level is usually around 3.5 to 4.5, which means it's slightly acidic. But don't worry, this acidity is not strong enough to cause any problems when you're cooking or baking. In fact, the acidity in vanilla extract can even help to balance out the flavors in your recipes and make them taste more delicious.
