METTLER TOLEDO’s wide range of benchtop and portable digital refractometers  measure refractive index and other related values, such as, Brix, invert sugar, HFCS42 or HFCS55 or other concentrations with high precision and a short measuring time.

Our portable refractometers provide automatic temperature compensation. They can be used in the lab or in the field, for instance for measuring Brix, Oechsle or the freezing point of ethylene glycol and propylene glycol/water mixtures .

Our benchtop refractometers have a built-in Peltier thermostat to accurately control the temperature so a water bath is not required. They can be connected to a density meter, spectrophotometer, pH meter, titrator or other instruments to measure several parameters simultaneously. Various automation units are available to further improve productivity.

Expertise
Our expertise is available on a dedicated website www.refractometry.com (easy to remember), with videos, animations, webinars and a variety of applications for food & beverage, pharmaceuticals, chemicals, and other industries.  Several workflow solutions show how to improve the accuracy of your measurement, avoid errors and increase the throughput. Download our free Refractive Index Measurement Guide to learn how to improve density measurement with digital density meters.

How do digital refractometers work?
Digital refractometers use the critical angle principle to measure the refractive index, with the aid of a light-emitting diode, a sapphire prism and a high-resolution optical CCD sensor. Our interactive animation will show you how this works.

What do refractometers measure?
Refractometers measure primarily the refractive index, a dimensionless number which describes how much light is bent, when entering a sample. This refractive index is often converted into other units (e.g. Brix, HFCS, %concentration) to give the corresponding information (Brix = sugar concentration, HFCS = Concentration of High Fructose Corn Syrup).

What are refractometers used for?
Refractometers are used in many areas to measure the physical property of a liquid, either to check a concentration (e.g. sugar concentration of grapes to estimate the alcohol level of a wine), to control incoming goods (check if the correct product has been delivered, before clearing it for production), to check the purity of a product (not diluted) or for final control of a finished product.

Do refractometers need calibration?
Yes, refractometers have to be calibrated once in a while. This is usually done with water, sometimes with Brix standards. It is recommended to perform a calibration only if the instrument has drifted. Regular testing with water, Brix standards or certified standards will detect any instrument drift.