The Brix of Fruit Juices relates to the level of dissolved solids, which for most fruit juices are the sugars. Broadly speaking, the expectation is that the higher the Brix the sweeter tasting will be the juice. After sugars, the next most abundant constituents are usually the fruit juice acids. The higher the total acidity, the sharper tasting will be the juice to a point where it becomes too acidic to consume directly.
A measure of the balance between juice sweetness and acidity can be expressed in terms of the proportion of Brix to Acidity, known as the Ratio.
The industry convention is to calculate the Ratio of a juice as the Corrected Brix divided by the total Acidity (as percentage by weight of anhydrous citric acid). (If an uncorrected Brix / RS figure is used, the Ratio will be approximately 0.2 points less).
The range of Ratios can be from as low as around 1 to 6 for juices such as Lime, Lemon, Blackcurrant and Passionfruit, to highs of 65 to 170 for the likes of Apple, Pear, Mango, Lychee and Grape. For the majority (of adults), juices with Ratio in the area of 10 – 30 tend to be preferred as having an acceptable balance of sweetness to sharpness. In the case of one of the most popular juices, Orange, it is bought and sold on the basis of Ratio.