Industrial Process Refractometers

Process refractometer
(K-Patents)

The ultimate focus of industrial refractometry is to describe the percentage of certain compounds in a final product. Refractometry, a combination of physics, materials, and chemistry, is the process which measures the composition of known substances by means of calculating their respective refractive indexes (RI). RIs are evaluated via a refractometer, a device which measures the curve, or refraction, resulting when the wavelength of light moves from the air into and through a tested substance. The unitless number given by the refractometer, usually between 1.3000 and 1.7000, is the RI. The composition of substances is then determined when the RI is compared to a standard curve specific to the material of the substance.

Common examples of industrial refractometry uses are measuring the salinity of water to determine drinkability; calculating the dissolved solids in liquor processing in pulp and paper production;  figuring beverages’ ratios of sugar content; and understanding the hydrocarbon content of motor fuels. Regarding pulp and paper, refractometry scrutinizes content of compounds in black and green liquor processing. Regarding food, refractometry has the ability to measure the glucose in fruit during the fermentation process. Because of this, those in food services know when fruit is at peak ripeness and, in turn, also understand the most advantageous point in the fruit’s “lifetime” to put it on the market.


Equipment manufacturers have developed numerous refractometer configurations tailored to specific use and application. Each has a set of features making it the proper choice for its intended application. Product specialists can be invaluable sources of information and assistance to potential refractometer users seeking to match the best equipment to their application or process.