Refractometers
Refractometers from KERN enable precise measurements of the refractive index – ideal for determining concentrations, densities, or sugar and salt content in liquids. Whether in laboratories, the food industry, or the medical field: the various models offer reliable results and user-friendly operation for professional requirements.
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Refractometers – Precise Analytics for Laboratories, Industry and Food Production
Refractometers are high-precision optical measuring instruments used to determine the refractive index of various media. From this value, essential parameters such as concentration, density, and the alcohol, sugar, or salt content can be calculated. Whether for quality control in food production, laboratory analysis, or artisanal use – refractometers from KERN deliver reliable measurement results for a wide range of applications.
Wide Product Range – The Right Device for Every Application
The KERN portfolio includes analog and digital refractometers, as well as special models for specific media:
✔ Analog handheld refractometers: Ideal for mobile use in agriculture, food inspection, or education. Compact, robust, and easy to use.
✔ Digital refractometers: For precise analysis with digital display and automatic temperature compensation (ATC). Battery-powered for flexible use – whether in the lab, production line, or field service.
✔ Special refractometers: Developed for specific applications, e.g., for analyzing urine, industrial oils, or coolants.
Versatile Applications – From Honey to Jewelry
Refractometers can be used in a wide range of industries:
✔ Food and beverage production: Monitor sugar content (Brix), alcohol levels, or salt concentration
✔ Beekeeping & honey production: Determine moisture content in honey to assess quality
✔ Wine, cider, and beer production: Monitor fermentation and maturity
✔ Medical & veterinary fields: Analyze urine specific gravity for diagnostic purposes
✔ Agriculture & education: Use in agricultural schools or professional training
✔ Jewelers & gemology: Determine refractive indices for material analysis
KERN – Precision with Tradition since 1844
As Germany’s oldest manufacturer of precision balances, KERN has stood for reliable measurement technology for over 180 years. Today, our product range includes not only high-quality laboratory and industrial scales but also advanced optical instruments such as refractometers, polarimeters and microscopes. The combination of proven mechanical engineering, modern optics and application-oriented development makes KERN & SOHN GmbH a trusted partner worldwide – from food production to pharmaceutical quality control.
Frequently Asked Questions (FAQ) – Refractometers
1. How does a refractometer work?
A refractometer measures the refractive index of a liquid. Depending on the composition, this value changes. From that, it is possible to determine:
✔ Concentration
✔ Density
✔ Sugar and salt content
Many refractometers include Automatic Temperature Compensation (ATC) to ensure accurate readings, even when ambient temperatures vary.
2. What types of refractometers are available?
Depending on accuracy requirements and application area, you can choose from:
✔ Analog handheld refractometers – durable, portable, cost-effective
✔ Digital handheld refractometers – precise, easy to use, with ATC
✔ ABBE refractometers – high-precision laboratory instruments for universal use
3. How do I use an analog refractometer?
The application is straightforward and requires only a few steps. Clean handling is important.
✔ Clean the prism
✔ Apply a few drops of the sample
✔ Close the cover plate
✔ Hold toward a light source and adjust focus if needed
✔ Read the value at the dividing line
✔ Clean the prism after measurement
4. What should I consider when using a digital refractometer?
These steps ensure proper handling and accurate results.
✔ Switch on the device (usually battery-powered)
✔ Clean the measuring surface
✔ Apply a few drops of the sample
✔ Start the measurement with a button press
✔ Read the digital result on the display
✔ Clean the measuring surface immediately after use
5. Which is better: analog or digital refractometer?
The choice depends on the application. Both types have specific advantages.
✔ Analog models: robust, portable, affordable – ideal for beekeepers, schools, agriculture
✔ Digital models: precise, simple to use, with ATC – ideal for laboratories and industry
✔ ABBE refractometers: laboratory devices for the highest precision.
6. What are the application areas for refractometers?
✔ Food and beverage (sugar content in juice, fruits, vegetables)
✔ Honey production (moisture content in honey)
✔ Winemaking and brewing (sugar, alcohol, fermentation monitoring)
✔ Salinity measurements (NaCl in water solutions)
✔ Urinalysis (serum density, diagnostics)
✔ Industry and automotive (glycol concentration, battery service, coolant monitoring)
✔ General determination of refractive index
7. What scales are used in refractometers?
Depending on the model and application, different scales may be available.
✔ Brix scale – sugar content in food and beverages
✔ Salinity – salt concentration in aqueous solutions
✔ Specific gravity or density – for example in urine or industrial fluids
✔ Multi-scale models – combine several scales in one device
8. How do I correctly read measurement results?
The method depends on the type of refractometer. Always calibrate the device before use.
✔ Analog: read the value at the dividing line in the visual field
✔ Digital: read the result on the display
✔ Clean the prism or measuring surface before each measurement
9. How are refractometers maintained and calibrated?
Proper maintenance ensures reliable and long-term precision.
✔ Clean only with a dry or slightly damp cloth – never use running water
✔ Protect from impacts, temperature changes, and fumes
✔ Calibrate as needed using distilled water or a reference solution
10. Do I need automatic temperature compensation (ATC)?
ATC is useful when measuring under changing ambient temperatures (10–30 °C). It automatically adjusts the refractive index reading.
✔ Yes: when used in fluctuating temperatures – ATC improves accuracy
✔ No: in a stable lab environment, manual correction is sufficient
11. What is a honey refractometer?
A honey refractometer is specially designed to measure moisture content in honey.
✔ Standard tool for professional and hobby beekeepers
✔ Ensures quality and shelf life of the honey harvest
12. How does a refractometer help with honey analysis*?
Measuring water content is essential for assessing honey quality and preventing fermentation.
✔ High water content increases the risk of fermentation
✔ Ideal range: 15–18% moisture
✔ Enables reliable quality control for all types of beekeepers
Source note: German Beekeepers Association (D.I.B.), DIN 10752, Codex Alimentarius FAO/WHO
13. What is a wine refractometer?
A wine refractometer measures sugar content in grape must.
✔ Helps determine the optimal harvest time
✔ Monitors fermentation process
✔ Provides a basis for calculating potential alcohol content
14. Why do winemakers and brewers use handheld refractometers?
Refractometers provide fast sugar content measurement in grape juice or brewing wort, which is crucial for controlling ripeness and fermentation.
✔ Monitoring ripeness of grapes or wort concentration
✔ Controlling fermentation progress
✔ Estimating alcohol content
In winemaking, °Brix or °Oechsle is used; in brewing, mostly °Brix (≈ °Plato).
15. What are typical °Brix values in beer** production?
The sugar content in wort (original gravity) varies by beer style. Refractometers help check these values before fermentation.
✔ Light or alcohol-free beer: 7–10 °Brix
✔ Pilsner or Helles: 11–13 °Brix
✔ Wheat beer or Export: 12–15 °Brix
✔ Bock or Doppelbock: 16–20 °Brix
Note: 1 °Brix is approximately equal to 1 °Plato. A refractometer with a Brix scale is usually sufficient for brewing applications.
16. What are typical °Brix and °Oechsle values in winemaking***?
The sugar content in grape must determines wine category and quality. The table below gives typical values:
✔ Early harvest / table wine: 15–18 °Brix | 60–75 °Oe
✔ Quality wine: 18–22 °Brix | 75–95 °Oe
✔ Late harvest / Auslese: 22–26 °Brix | 95–110 °Oe
✔ Beerenauslese / Ice wine: 26+ °Brix | 110+ °Oe
Tip: For international use, multi-scale refractometers (Brix/Oechsle/KMW) offer maximum flexibility.
17. What are refractometers used for in industrial settings?
In industrial environments, refractometers enable fast and reliable analysis of process liquids:
✔ Testing coolants, lubricants, or chemicals
✔ Preventing tool wear
✔ Ensuring consistent product quality
✔ On-site testing without laboratory equipment
18. How is a refractometer used to check coolant concentration?
In metalworking, water-based coolants are mixed from concentrate and water. The correct ratio is crucial for tool life, corrosion protection, and machining quality.
Example:
Reading: 4.0 °Brix
Correction factor: 1.5
---> Concentration = 4.0 × 1.5 = 6.0% – in the optimal range
✔ Early detection of too high or low concentration
✔ Prevention of bacteria growth, corrosion, or skin irritation
✔ No lab analysis required – ideal for daily use
19. How is a refractometer used for antifreeze measurement?
Glycol-based antifreeze mixtures in vehicles or cooling systems must be checked regularly to avoid freeze damage.
Refractometers show the freezing point directly in °C
Example: –38 °C --> excellent protection
Values above –25 °C may be insufficient
✔ Easy monitoring in automotive workshops, heating systems, or industrial plants
✔ No chemical handling
✔ Refractometers with pre-configured glycol scales are available
Buy Your Refractometer Now!
Precision meets versatility – with a refractometer from KERN & SOHN, you get a robust and highly accurate measuring instrument that can be used flexibly across a wide range of industries. Our large selection of models ensures the right solution for every application.
Our experts are happy to assist you – contact us by
Phone: +49 (0) 7433 / 9933-562
Email: info.sauter@kern-sohn.com
Source note on the technical target values for beer, wine and honey:
*The specified optimal moisture content in honey (15–18%) is based on the quality guidelines of the German Beekeepers Association (D.I.B.), DIN standard 10752, as well as international standards such as the Codex Alimentarius FAO/WHO – Honey Standard.
**The °Brix values given for different beer styles are based on the Style Guidelines of the Brewers Association, the technical specifications of the European Brewery Convention (EBC), as well as specialist portals such as braumagazin.de and bierwiki.org. The conversion °Plato ≈ °Brix corresponds to common industry practice.
***The target ranges for °Oechsle and °Brix values in grape must are derived from the standards of the International Organisation of Vine and Wine (OIV), the German Wine Law (§ 9 Wine Ordinance), as well as information provided by vintners’ associations such as VDP and DWV.
Refractometers are high-precision optical measuring instruments used to determine the refractive index of various media. From this value, essential parameters such as concentration, density, and the alcohol, sugar, or salt content can be calculated. Whether for quality control in food production, laboratory analysis, or artisanal use – refractometers from KERN deliver reliable measurement results for a wide range of applications.
Wide Product Range – The Right Device for Every Application
The KERN portfolio includes analog and digital refractometers, as well as special models for specific media:
✔ Analog handheld refractometers: Ideal for mobile use in agriculture, food inspection, or education. Compact, robust, and easy to use.
✔ Digital refractometers: For precise analysis with digital display and automatic temperature compensation (ATC). Battery-powered for flexible use – whether in the lab, production line, or field service.
✔ Special refractometers: Developed for specific applications, e.g., for analyzing urine, industrial oils, or coolants.
Versatile Applications – From Honey to Jewelry
Refractometers can be used in a wide range of industries:
✔ Food and beverage production: Monitor sugar content (Brix), alcohol levels, or salt concentration
✔ Beekeeping & honey production: Determine moisture content in honey to assess quality
✔ Wine, cider, and beer production: Monitor fermentation and maturity
✔ Medical & veterinary fields: Analyze urine specific gravity for diagnostic purposes
✔ Agriculture & education: Use in agricultural schools or professional training
✔ Jewelers & gemology: Determine refractive indices for material analysis
KERN – Precision with Tradition since 1844
As Germany’s oldest manufacturer of precision balances, KERN has stood for reliable measurement technology for over 180 years. Today, our product range includes not only high-quality laboratory and industrial scales but also advanced optical instruments such as refractometers, polarimeters and microscopes. The combination of proven mechanical engineering, modern optics and application-oriented development makes KERN & SOHN GmbH a trusted partner worldwide – from food production to pharmaceutical quality control.
Frequently Asked Questions (FAQ) – Refractometers
1. How does a refractometer work?
A refractometer measures the refractive index of a liquid. Depending on the composition, this value changes. From that, it is possible to determine:
✔ Concentration
✔ Density
✔ Sugar and salt content
Many refractometers include Automatic Temperature Compensation (ATC) to ensure accurate readings, even when ambient temperatures vary.
2. What types of refractometers are available?
Depending on accuracy requirements and application area, you can choose from:
✔ Analog handheld refractometers – durable, portable, cost-effective
✔ Digital handheld refractometers – precise, easy to use, with ATC
✔ ABBE refractometers – high-precision laboratory instruments for universal use
3. How do I use an analog refractometer?
The application is straightforward and requires only a few steps. Clean handling is important.
✔ Clean the prism
✔ Apply a few drops of the sample
✔ Close the cover plate
✔ Hold toward a light source and adjust focus if needed
✔ Read the value at the dividing line
✔ Clean the prism after measurement
4. What should I consider when using a digital refractometer?
These steps ensure proper handling and accurate results.
✔ Switch on the device (usually battery-powered)
✔ Clean the measuring surface
✔ Apply a few drops of the sample
✔ Start the measurement with a button press
✔ Read the digital result on the display
✔ Clean the measuring surface immediately after use
5. Which is better: analog or digital refractometer?
The choice depends on the application. Both types have specific advantages.
✔ Analog models: robust, portable, affordable – ideal for beekeepers, schools, agriculture
✔ Digital models: precise, simple to use, with ATC – ideal for laboratories and industry
✔ ABBE refractometers: laboratory devices for the highest precision.
6. What are the application areas for refractometers?
✔ Food and beverage (sugar content in juice, fruits, vegetables)
✔ Honey production (moisture content in honey)
✔ Winemaking and brewing (sugar, alcohol, fermentation monitoring)
✔ Salinity measurements (NaCl in water solutions)
✔ Urinalysis (serum density, diagnostics)
✔ Industry and automotive (glycol concentration, battery service, coolant monitoring)
✔ General determination of refractive index
7. What scales are used in refractometers?
Depending on the model and application, different scales may be available.
✔ Brix scale – sugar content in food and beverages
✔ Salinity – salt concentration in aqueous solutions
✔ Specific gravity or density – for example in urine or industrial fluids
✔ Multi-scale models – combine several scales in one device
8. How do I correctly read measurement results?
The method depends on the type of refractometer. Always calibrate the device before use.
✔ Analog: read the value at the dividing line in the visual field
✔ Digital: read the result on the display
✔ Clean the prism or measuring surface before each measurement
9. How are refractometers maintained and calibrated?
Proper maintenance ensures reliable and long-term precision.
✔ Clean only with a dry or slightly damp cloth – never use running water
✔ Protect from impacts, temperature changes, and fumes
✔ Calibrate as needed using distilled water or a reference solution
10. Do I need automatic temperature compensation (ATC)?
ATC is useful when measuring under changing ambient temperatures (10–30 °C). It automatically adjusts the refractive index reading.
✔ Yes: when used in fluctuating temperatures – ATC improves accuracy
✔ No: in a stable lab environment, manual correction is sufficient
11. What is a honey refractometer?
A honey refractometer is specially designed to measure moisture content in honey.
✔ Standard tool for professional and hobby beekeepers
✔ Ensures quality and shelf life of the honey harvest
12. How does a refractometer help with honey analysis*?
Measuring water content is essential for assessing honey quality and preventing fermentation.
✔ High water content increases the risk of fermentation
✔ Ideal range: 15–18% moisture
✔ Enables reliable quality control for all types of beekeepers
Source note: German Beekeepers Association (D.I.B.), DIN 10752, Codex Alimentarius FAO/WHO
13. What is a wine refractometer?
A wine refractometer measures sugar content in grape must.
✔ Helps determine the optimal harvest time
✔ Monitors fermentation process
✔ Provides a basis for calculating potential alcohol content
14. Why do winemakers and brewers use handheld refractometers?
Refractometers provide fast sugar content measurement in grape juice or brewing wort, which is crucial for controlling ripeness and fermentation.
✔ Monitoring ripeness of grapes or wort concentration
✔ Controlling fermentation progress
✔ Estimating alcohol content
In winemaking, °Brix or °Oechsle is used; in brewing, mostly °Brix (≈ °Plato).
15. What are typical °Brix values in beer** production?
The sugar content in wort (original gravity) varies by beer style. Refractometers help check these values before fermentation.
✔ Light or alcohol-free beer: 7–10 °Brix
✔ Pilsner or Helles: 11–13 °Brix
✔ Wheat beer or Export: 12–15 °Brix
✔ Bock or Doppelbock: 16–20 °Brix
Note: 1 °Brix is approximately equal to 1 °Plato. A refractometer with a Brix scale is usually sufficient for brewing applications.
16. What are typical °Brix and °Oechsle values in winemaking***?
The sugar content in grape must determines wine category and quality. The table below gives typical values:
✔ Early harvest / table wine: 15–18 °Brix | 60–75 °Oe
✔ Quality wine: 18–22 °Brix | 75–95 °Oe
✔ Late harvest / Auslese: 22–26 °Brix | 95–110 °Oe
✔ Beerenauslese / Ice wine: 26+ °Brix | 110+ °Oe
Tip: For international use, multi-scale refractometers (Brix/Oechsle/KMW) offer maximum flexibility.
17. What are refractometers used for in industrial settings?
In industrial environments, refractometers enable fast and reliable analysis of process liquids:
✔ Testing coolants, lubricants, or chemicals
✔ Preventing tool wear
✔ Ensuring consistent product quality
✔ On-site testing without laboratory equipment
18. How is a refractometer used to check coolant concentration?
In metalworking, water-based coolants are mixed from concentrate and water. The correct ratio is crucial for tool life, corrosion protection, and machining quality.
Example:
Reading: 4.0 °Brix
Correction factor: 1.5
---> Concentration = 4.0 × 1.5 = 6.0% – in the optimal range
✔ Early detection of too high or low concentration
✔ Prevention of bacteria growth, corrosion, or skin irritation
✔ No lab analysis required – ideal for daily use
19. How is a refractometer used for antifreeze measurement?
Glycol-based antifreeze mixtures in vehicles or cooling systems must be checked regularly to avoid freeze damage.
Refractometers show the freezing point directly in °C
Example: –38 °C --> excellent protection
Values above –25 °C may be insufficient
✔ Easy monitoring in automotive workshops, heating systems, or industrial plants
✔ No chemical handling
✔ Refractometers with pre-configured glycol scales are available
Buy Your Refractometer Now!
Precision meets versatility – with a refractometer from KERN & SOHN, you get a robust and highly accurate measuring instrument that can be used flexibly across a wide range of industries. Our large selection of models ensures the right solution for every application.
Our experts are happy to assist you – contact us by
Phone: +49 (0) 7433 / 9933-562
Email: info.sauter@kern-sohn.com
Source note on the technical target values for beer, wine and honey:
*The specified optimal moisture content in honey (15–18%) is based on the quality guidelines of the German Beekeepers Association (D.I.B.), DIN standard 10752, as well as international standards such as the Codex Alimentarius FAO/WHO – Honey Standard.
**The °Brix values given for different beer styles are based on the Style Guidelines of the Brewers Association, the technical specifications of the European Brewery Convention (EBC), as well as specialist portals such as braumagazin.de and bierwiki.org. The conversion °Plato ≈ °Brix corresponds to common industry practice.
***The target ranges for °Oechsle and °Brix values in grape must are derived from the standards of the International Organisation of Vine and Wine (OIV), the German Wine Law (§ 9 Wine Ordinance), as well as information provided by vintners’ associations such as VDP and DWV.