However, a historical index of ripeness suggests that optimal sugar / acidity balance is achieved if the product of the Brix value times the square of the pH is in the range of 220 to 260. For example, a 22† Brix juice at pH 3.2 would yield a value of 225.3. Late harvest fruit at a higher pH (24† Brix at pH 3.6, for example) would yield a value (311) outside of this range.