Anecdotal sources suggest that Granny Smith Apples are acidic as it has a pH of up to 6.9
pH is essentially a measure of acidity, and it uses a scale ranging from 0-14. Neutral pH, which is neither acid nor basic, is 7.0. A pH below 7.0 is considered acid, with lower numbers being more acidic (for example, 3 is more acidic than 6).
A pH above 7.0 is basic (or alkaline), and 13 is far more basic than 10. The scale is logarithmic, meaning that a pH of 5.0 is 10 times more acidic than a pH of 6.0 – not just 1 time more acidic. (This could also be interpreted to mean that pH 6.0 is 10 times more basic than 5.0, even though both are considered acidic.).
Granny Smith apples are a crisp, tart apples that make a delicious snack or a tasteful addition to recipes. Because these green apples have a higher acid content than other apples, they take longer to go brown once you cut into them.
No matter how you enjoy these tart green apples, your body will reap a nutritional harvest of benefits. Check out the health benefits of Granny Smith Apples at Sfgate.com.