The Brix Refractometer shows the concentration percentage of the soluble solids content (Total Solids) of a sample (water solution). The soluble solids content is the total of all the solids dissolved in the water – beginning with sugar, salts, protein, acids, etc. and the measurement reading value is the value of the sum total of those. Essentially Brix is calibrated to the number of grams of cane sugar contained in 100g of cane sugar solution. So, when measuring a sugar solution, the Brix should perfectly match the actual concentration. With solutions of other components, a conversion chart is used.