Total soluble solids are solids that are dissolved within a substance. A common total soluble solid is sugar. The technique of measuring the concentration of total soluble solids is called refractometry, and it is used extensively in the food industry.
In research, the Brix scale is used to measure the amount of total soluble solids dissolved within a substance. It is commonly used to measure sugar content in drinks and medicines.
The Brix scale measures the percentage of total soluble solids in a substance per 100 grams. For example, a 25 percent Bx solution would contain 25 grams of soluble solids per 100 grams of solution.