Brix is another common standard measurement for sugars in grapes or grape must. Winemakers use a special instrument to measure the content of sugars in a liquid. 

By taking the number of brix you get in a measurement and multiplying it by .55, a winemaker will know roughly how much alcohol they will get in the fermented wine. A juice that has 22 brix will produce a wine with around 12% ABV.