Digital Refractometer - J157 High Accuracy for Food, Beverage, Water Based Chemicals, & Sugar Industries.

Rudolph Research Analytical, working together with refractometer (Refraktometer) users from various countries and disciplines, has developed the J157 Automatic Digital Refractometer. The Rudolph J157 benchtop combines features and accuracy that meet the most demanding applications both in and out of the laboratory.


Application - Food and Chemical Labs

The J157 is designed as a high accuracy automatic refractometer for food and water based chemical applications. The instrument can read to ±0.00002 RI / ±0.01 BRIX making it more accurate and reproducible than 4 decimal place wide range chemical refractometers.


Refractometer Operation

Operating the J157 is as simple as placing a sample on the prism, closing the cover and reading the answer – all in just a few seconds. There are no shadow lines to match and there is no eyepiece requiring any type of operator determination or manual adjustment as necessary with ABBE type refractometers. When the “measure when stable mode” is selected, the J157 automatically waits until the sample has been electronically heated or cooled to a predefined temperature before initiating a measurement.


Dual Electronic Temperature Control System

Unlike other temperature controlled refractometers, the J157 has electronic temperature control from both above and below the sample. The sample cover is controlled to the same temperature as the prism and, when lowered, is designed to provide a temperature controlled micro-environment that provides unrivaled temperature stability, fast measurement time and minimal evaporation. Depending on options, the sample cover can also be used to initiate an automatic measurement.


Optional Sample Presser

The J157 digital refractometer is available with an optional Temperature Controlled Sample Presser that touches the sample. Compared with the standard temperature controlled cover, the optional presser reduces the empty volume of the measurement area thereby greatly reducing evaporation and at the same time helping to evenly spread many types of materials including semi solids, and pastes over the measurement prism. This feature offers improved measurement performance on many samples.


Auto Measure Option

The Rudolph Auto Measure Option allows the closing and opening of the presser to start and end a measurement. The operator just closes the cover to start measuring and lifts the cover to stop measuring. The closing and lifting of the lid functions as the start/stop in the measurement process without ever touching the measure button.


Easy to Clean Refractometer Sample Well

No matter how great the refractometer is, accurate results will only be obtained if the prism is clean. The Rudolph J Series offers a flat, easy to clean prism that makes the cleaning process between measurements simple, even with sticky samples.


User Defined Scales

The J157 can be supplied with a large range of standard and customized scales. Scales can be customized in a few minutes. Simply enter 2, 6 or 10 points of concentration vs. corresponding RI data, and the instrument calculates the custom scale automatically.



The J157 offers 1 point, 2 point or a full multi-point calibration. Calibration can be done at 20°C, 25°C or any user selectable temperature within the available range. Regardless of how many times the refractometer has been calibrated, it can always be restored to the initial factory calibration if required.

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