Refractometer

If you're in need of a refractometer, you've come to the right place. To help you determine which refractometer model will best meet your needs, ask yourself the following questions before purchasing.

Do you need a portable or stationary refractometer?
Your answer to this question depends largely on the nature of the refractomer's intended use. Will you be measuring the refractive index in a laboratory or on a manufacturing production line where you will remain in the same place taking repetitive measurements with your refractometer oe handheld refractometer? Or will you be measuring the refractive index on the go, in the field or in many different scenarios and locations?

An Abbe refractometer typically is a tabletop or benchtop device for stationary use. Analog or digital handheld refractometers usually are lightweight and portable, with some even capable of being stored in your pocket. These pocket-size refractometers especially are handy for taking on-the-spot measurements in breweries, vineyards and even automotive body shops.

What measurement accuracy is required?
An analog handheld refractometer with an optical reading scale should have an accuracy of ± 0.5% Brix. A modern digital handheld refractometer should have an accuracy of ± 0.2% Brix. The accuracy of an ABBE refractometer should be ± 0.3% Brix.

Because refractive index is temperature dependent, to ensure the most accurate measurement readings using any refractometer, it is important to allow the sample, refractometer and ambient temperatures to equalize before measuring. This step is essential, even when using a refractometer with automatic temperature compensation. To know whether the temperatures have come to an equilibrium, take five measurements in a row. The readings should not vary by more than the stated accuracy or precision of the refractometer.

Is a calibration certificate needed for your refractometer?
All refractometers from PCE Instruments (PCE) are manufacturer or factory calibrated. PCE's Abbe and handheld refractometer models also can be zeroed or calibrated at any time by the user.

For companies requiring an ISO calibration certificate, many PCE refractometer products can be calibrated in an ISO-certified laboratory environment against certain reference standards (certified test fluids). Refractometer models with an ISO calibration option will feature an ISO calibration certificate as an accessory available for an additional fee.

In the following, you can see some example indicator scales of some refractometers. If the measurement parameters you require are not available with the products we offer, please do as described below or get in touch with our engineers and technicians who are happy to give advice on our refractometers

For example, if the result is 12.9 % Brix, you can do a dry test of the same substance in a drying cabinet or a chemical analysis of it in a laboratory. In this example, the result is 8.2 % solids content.

You now have to divide the two results (12.9 : 8.2). Result = 1.57. Now you know the correlation between the refractometer and the laboratory result. If you now use the refractometer for in-process or field measurements, you only need to divide the measured value by 1.57 to get the actual laboratory value.

Follow the links to find some more information about our refractometers (Conversion charts )  as well as detailed instructionsto compare refractive values measured by different refractometers. Lots of our refractometers display the reading in degrees Brix. A liquid has one degree Brix (=1 % Brix) if it has the same density as a solution of 1 g of sucrose in 99 g of water. It has 10 Brix (=10 % Brix) if it has the same density as a solution of 10 g of sucrose in 90 g of water. The sucrose serves as the reference for the sugar content.

The amount of soluble dry solids in a liquid (and thus approximately the sugar content) is usually displayed in "degrees Brix" (° Brix). This indirectly provides an objective value of the ripeness of a fruit. Some EC marketing standards (e. g. for kiwi fruits and melons) now stipulate that a „sufficiently ripe“ fruit must fulfil certain Brix values. This unit of measurement which is very common in the use of refractometers is named after Adolf F. Brix, a scientist of the 19th century who developed this calibration in 1870 in order to determine the sugar content of liquids. The EC marketing standards for kiwi fruit and melons / watermelons expressly stipulate that the Brix value must be measured with a refractometer in order to determine the harvest maturity of fruit.

The Abbe refractometer is a special type of refractometer. This type of refractometer is an optical device that determines the refractive index of liquids. It is a total refractometer, which means that its measuring principle is based on the fact that the critical angle of the total reflection at an interface depends on the refractive indices of the involved optical media. The total reflection takes place at the interface between the glass prism with a known, high refractive index and the liquid to be measured which is optically thinner and has a lower refractive index. The interior design of the Abbe refractometer enables precise determination of the critical angle with a thin liquid layer which is applied between two glass prisms. These refractometers are available in our online shop.

Modern technological development accelerates many industrial processes and requires from the producers both, high quality and at the same time efficient work without procrastinations and long standstills. Therefore, continuous monitoring and checks are not only important, they are mandatory for those who want to stay on the market and have the reputation of the producers of the high-quality products. Control of the raw material, semi-product as well as the final product, modernization of the methods of the control at different stages of the production – these are the tasks that the manufacture tries to fulfill with the help of the modern digital devices. Refractometer is one of them.

When it goes about food industry, quality and safety of the product are essential. Refractometer is a very sensitive device which delivers accurate measurement results and can be used whenever the check is required. In the food industry refractometer is applied to test the sugar level (Brix), for example, in the production of sweets at the pastry factories, beverages and juices or different types of baked products (pastries, cakes, pies, cookies). Determination of the content of the dry soluble substances in the food stuffs like various dairy products, fruit or vegetable mashed products is also carried out with the refractometer. Besides, it may detect the amount of water in the substance. The measurement values obtained with the help of the refractometer can be immediately used for the adjustments, if the values deviate from the norm range. For each final product there are specified norms as for water/sugar/dry substance content. Continuous monitoring allows ensuring the compliance with the norms.

If it goes about industrial application, the refractometers can be mounted directly near the conveyor, container or pipe, in other words, in-built in the immediate production line. In this case, there is no need to take the sample and carry out the measurement separately. Handheld devices, though, need a very small amount of sample of the stuff to be checked, which makes them very convenient for immediate occasional checks wherever it may be required.

Determination of the Concentration of Potato Starch with the help of a Refractometer
Potato starch is not only used in cooking and in the food industry as a binding agent. The carbohydrate starch from potatoes and other crops can also be used to produce biodegradable packaging materials, disposable tableware and as a base for tablets, ointments or detergents. In the paper and cardboard production, starch and starch products are used, among other things, for gluing, to improve tear strength and for surface finishing. Processed starch can also be used as a binder in paints and adhesives, for example in wallpaper paste, on envelopes and stamps.

Special potato varieties are bred for starch production, for which the taste or cooking properties are not important, but only the high starch content. However, the starch content of the harvested potatoes also varies within one variety depending on the location and the respective weather conditions. The usual methods for determining the starch content in table and industrial potatoes use the relationship between starch content and density of the potatoes. To determine the density, the potatoes are either weighed above and below water with so-called potato scales or immersed in salt baths of different concentrations. Since these methods are relatively costly, the ways are being sought to integrate the reliable methods for determining the starch content into the large sorting plants.

Refractometers with starch scaling can be used for rapid determination of already dissolved starch. A drop of liquid is sufficient to determine the proportion of dissolved starch via light refraction. The measuring range of one of these purely optical refractometers can, for example, be designed for zero to thirty percent of starch and the scale for a reading accuracy of 0.2 percent. Special refractometers have also been developed for process monitoring and control in industry, which can continuously measure and display the proportion of starch and transmit the measured values to other devices.

Refractometer for determining the sugar content in jams
The sugar content not only influences the taste but also the shelf life of fruit preparations. According to the German Jam Ordinance, the sugar content of products sold as jams, jellies or marmalades must be at least sixty per cent in total. Only in the case of calorie-reduced products the sugar contents re lower and the addition of preservatives is permitted. Since part of the sugar comes from the fruit and this amount depends on the type of fruit and the degree of ripeness, the total sugar content is measured for each batch prepared. The regulation on jams and some similar products states in paragraph 3 that the total sugar content must be indicated in grams per hundred grams of total mass. It explains that the figure to be indicated corresponds to the value of the sucrose scale at 20 degrees Celsius determined with a refractometer.

Many refractometers have a scale division or digital display in degrees Brix. One degree Brix corresponds to one gram of sucrose in one hundred grams of solution and thus the Brix value is exactly the numerical value required in the regulation. The measurement results are temperature-dependent. If it cannot be ensured that the measurements are taken at 20 degrees Celsius, the refractometer with automatic temperature compensation should be used. For the constant checks in the production process the refractometers for fixed installation have been developed in which the measurements are electronically evaluated and the results are automatically forwarded. Depending on the sugar content of the fruit and the desired target composition, the sugar addition can then be automatically adjusted.

Refractometers with Brix scales are available with different measuring ranges. The smaller the measuring range, the more finely the display scale can be subdivided. For the measurement of sugar concentration, however, it is above all important that the measuring range fits the application and covers all the relevant values. The refractometer suitable for winemakers, for example, shows values from 0 to 44 degrees Brix or percent Brix, while for jams, honey and concentrated juices, especially the values above 45 degrees Brix should be measured.

The process of beer brewing requires a lot of attention and accuracy, especially when it goes about producing beer with the same taste and of the same quality. Since this beverage contains alcohol, it is a challenge to ensure the repeatability and that is why continuous monitoring of the raw material and also the values during the brewing process is necessary. Each time there may be slight difference in the parameters of the ingredients required for beer brewing. By applying the refractometer it is possible to check the specific gravity of the beer wort and the alcohol content / strength of the product at all the stages, and thus, if the deviations occur, react to this correspondingly.

Besides specific gravity, the sugar content is another also very important parameter, to determine which also the refractometer is applied. Brix scale available in the refractometers used in brewing helps to assess the strength of the product. The application of the refractometer is so uncomplicated that it may be used for beer brewing at home who does this as hobby. When choosing an appropriate refractometer, it is necessary to pay attention to tis specifications, since for different measurements different devices may suit more than the other models. Beer wort is a specific material and one should be careful not to make a mistake when measuring by means of the refractometer.

A corresponding calibration and the measurement of the correction coefficient is required to achieve the accurate application of the refractometer. Wort contains not only water or sugar, but also a few other ingredients, depending on the type of beer to be produced. There is no one single value that is considered to be the reference, and each brewery calculates the appropriate correction factor for their products. Specific gravity of the wort measured by means of the refractometer is one of the most crucial parameters in this process. When the correction coefficient is determined, the measurements of the specific gravity of the wort are carried out quickly and this is advantageous for the process, since the brewer may regulate the process, shorten or prolong certain procedures (washing or boiling) as well monitor the whole fermentation process to achieve the best quality.

Besides targeted application, like brewing or sugar content measurement, refractometer finds its application in research and development. The method, the work of the refractometer is based on, is perfect for determining various parameters of the substances and solutions, which is helpful in analysis of the compounds, both from structural and chemical sides, for example, creation of the medical solutions or check of their concentration. It can be used for many experiments and researches, in pharmaceutical industry, chemical or medial sphere, industrial field, manufacturing, automotive industry, in particular maintenance of the vehicles. The convenience of application of this device is explained by its design and functions it may perform. For example, the presence of the temperature compensation function makes it very convenient for the laboratory applications. Refractometer provides help in studying blood tests and analysis of the essential parameters in the human body. When the substances are studied carefully in the laboratory or, for example, at the factory or enterprise, the laboratory refractometers and stationary devices are the best choice. The better choice for occasional or spontaneous tests is digital or handheld devices. They allow the user to get an immediate idea about the process, to carry out control check or some measurements on-site, where there is no possibility to use the stationary equipment.

The advantage of their application for researches is that the measurements are carried out quickly and not much preparation if required. The device should be appropriately calibrated, depending on the measuring task, and the correct maintenance and cleaning of the refractometer is mandatory. Some devices are able to convert the measurements into different units, without the need to carry out complicated calculations, as well as to measure the gravity and refraction factor. Application is possible in both, liquid and thick materials, which widens the range of the fields of use. Simple design, easiness of operation, reliability and accuracy, long-service life on condition of correct maintenance, possibility of no-battery work all these features make the refractometer an indispensable device in research and development of new substances, materials and products.

Inline Refractometer
Application of the modern measuring devices helps to bring many manufacturing and controlling processes on an absolutely new qualitative level. Refractometer is one of such devices, and finds its application in many areas, like chemical, food industry. The use of the knowledge about behavior of light in different media allows carrying out very precise structural analysis of many substances, defining their parameters and components in the complex compounds. The value of application of the refractometer cannot be underestimated or underrated. Starting from the laboratory use to the industrial application, the device is indispensable, since it helps to control many substances and many technological processes on an absolutely new and much better level.

Depending on the needs and requirements of the user, different model of the refractometer may be selected. For simpler tasks portable devices are the best choice, but if it goes about complicated technological processes and the continuous monitoring, then inline refractometer is taken.

The inline refractometer is a device that is capable of measuring in real time and that is why is most suitable when continuous or regular control of the complicated processes is required. Moreover, they help to carry out a very thorough and accurate control of the quality of the liquid and its composition and concentration, for example, beverage, chemical substance or other liquid medium. Among the advantages of the inline refractometers are high accuracy, and resistance to the influence of the external factors, such as contaminants or ambient conditions. The measuring range of the industrial (another name for inline devices) refractometers is much wider than of the portable ones and that is why the most demanding and challenging measuring tasks should be fulfilled with the help of these models.

Factories and manufacturing enterprises usually deal with the batch production and big lots. Control of the quality and correct proportion is extremely important, for example, in food industry when it goes about beverages, drinks, juices, various sauces, spirits, brines, pickled products, ketchups, dairy products and many other things. Before raw stuff becomes a final product, it should go through many stages, such as mixing, brewing, dissolving or diluting, warming-up or cooling-down. Besides, only the strict observance of proportion (sugar, salt, acid, vinegar and other substances) ensures that the final product will possess the required qualities or taste. All these can be not only checked, but continuously controlled with the help of the inline refractometer. Maintenance of the high quality is the priority for many famous producers and is important for the young companies that wish to win a position on the market and gain popularity among the customers.

With the help of the refractometer mistakes that may happen during the production can be avoided, timely detected and eliminated. Installation of the refractometers for real-time measurements allows very precise detection of the point where the fault happens, and thus, it helps to prevent the spoilage of a big amount of product, since if the fault is detected only at the end of the process, it is irreversible.

When it goes about food production, it is extremely important that the described nutrition information coincides with the reality, since it goes about health of people and for people who especially check for certain parameters because of their health condition, it is essential, for example, the sugar content should not be higher than described.

Not only in the food industry control of the production line is mandatory. It also applies to chemical and pharmaceutical industries. In the daily life a wide range of liquid agents is used for numerous applications: cleaning agents, lubricants, solvents, alkaline solutions, antifreeze or various additives. Even though they are not for consumption, the quality of these substances is not less important, since their application is often very effective, but also dangerous, and the observance of the correct composition is a pledge that under condition of correct application and observance of all the safety norms, no negative effects occur and, for example, the surfaces on which they are applied, are not damaged.

Nowadays the attention to the environment is permanently increasing, and the requirements to the production processes and, in particular, to the waste disposal are getting stricter and stricter. Sewage waters that come as disposal after the production should not contain harmful and dangerous substances in excessive amounts and their quality is also strictly controlled and regulated by the norms. Refractometer installed in the sewage facilities helps to keep this part of the production under control successfully.

Industrial or inline refractometer is not cheap, but taking into account the advantages and benefits which the enterprise gets after its installation in the production line, it may be said that it is a purchase that always pays off quickly by helping to maintain the quality, save the production of the spoiled and unsuitable for application goods, improve the automatization of the process and avoid downtime of the equipment, since the measurements take place in real time.

Should you require additional assistance in determining the right refractometer product for your application, please don't hesistate to contact us at or +44 (0) 2380 987 035 for PCE Instruments UK, or or +1 (561) 320-9162 for PCE Americas Inc.