Breaking down the pros and cons of optical and digital refractometers for use in the food industry.

Most commonly used in the food and beverage industry to measure sugar (°Brix), a refractometer tracks an optical constant and uses this information to reveal characteristics of the materials it is testing. Put simply, the speed of light is constant when recorded in a vacuum, but decreases whenever it passes through a material. The ratio of these two speeds is the optical constant known as the refractive index.  

Although it’s interesting to think about the science behind this process, refractometers save you the trouble of thinking too hard. Instead, you can rely on this ingenious piece of kit to reveal everything from sugar and salinity levels to glucose and fructose. You can also focus your attention on choosing between an optical and digital refractometer – using our honest comparison to weigh up your options. 

On the subject of honesty, we wanted to be upfront about the fact that Klipspringer supplies both optical refractometers and digital refractometers. With this in mind, we have endeavoured to be as unbiased as possible – drawing on our 22 years of experience and sharing only the most relevant insights. Our goal is always for you to make the right decision for you and your site, and we hope this overview helps to make this possible. 

Optical Refractometers

First, let’s consider the benefits of an optical refractometer. With a durable rubber grip, replaceable prism flap, and a well-balanced design that sits in the palm of your hand, this robust piece of equipment is suited to the daily demands of factory life. It is also IP65 water resistant and doesn’t require any batteries or power source.  

Recognised by operatives across the country and favoured by workers who have a tentative relationship with technology, optical refractometers are a tried and tested solution. This model is a great fit for simple factory applications, as it can measure within an extremely specific range. Measuring a more significant range proves to be a problem though, with many factories having to purchase multiple units to cover the ranges relevant to their processes.  

At Klipspringer we provide optical refractometers that work within the following parameters: 

Unlike a digital refractometer, it isn’t possible to purchase an optical unit that covers 0-95%. This is because as the range of an optical refractometer increases, it becomes more and more difficult to secure accurate results. With optical refractometers already open to human error, this is a risk that factories can’t afford to take.  

Instead of benefiting from the clear LCD display of its digital counterpart, the optical refractometer must be read by an operator through an eye piece that is held up to the light. Although this is a fairly straightforward process, there is always the possibility of results being impacted by an operative that has poor vision, doesn’t fully understand what they’re looking for, or is rushing through their duties. By comparison, the digital refractometer takes two seconds to display an accurate reading that doesn’t need to be interpreted.

View the Eclipse Optical Refractometer

Digital Refractometers

In recent years, we have seen a major shift towards digital refractometers, with the possibility of optical models being phased out entirely. This is because units such as the OPTi Digital Handheld Refractometer not only cover the full 0-95 Brix scale in one unit, but also boast an onboard library of 50 common scales. These scales include: 

  • °Brix 
  • Fructose 
  • Glucose 
  • Maltose 
  • Invert Sugar
  • Total Solids of Waste Milk
  • Salinity (NaCl) 
  • °Butyro 
  • Mass Sugar (°Brix) 
  • Alcohol Probable (AP) 
  • °Baumé
  • °Plato
View the complete list

This digital monitor also allows you to pre-set up to three scales, empowering your operatives to move between, for example Brix, Alcohol Probable, and Fructose, with just the touch of a button. This should result in huge savings on time and effort. It will also allow you to de-skill this aspect of your operation, as workers of all abilities will be able to easily operate this piece of kit. 

The key point that could cause a factory to hesitate before investing in a digital refractometer is the slightly higher price point. There is also the ongoing cost of replacing the unit’s batteries. Even with this in mind, we’ve found that once a technical manager considers the time saving benefits of a digital refractometer, they can identify the long-term savings.

Another factor that informs their decision making is the fact that digital refractometers cover the full 0-95 Brix scale. This allows them to purchase just the one unit, as opposed to multiple optical versions. Finally, with 10,000 readings provided by two AAA batteries, this small expenditure doesn’t undermine the overall benefits.  

View the OPTI Handheld Digital Refractometer

Key Points to Consider

Digital Refractometers:

  • Increased accuracy 
  • Durable IP65 rated body 
  • Read time of two seconds per sample 
  • 10,000 readings on two AAA batteries 
  • 50 scales available 
  • Option to pre-set three different scales 
  • Full 0-95 Brix range (and 1.33-1.53 RI) 
  • Stainless steel prism dish to stabilise sample temperature 
  • Slightly higher price point 
  • Additional cost of batteries and calibration 

Optical Refractometers:

  • Smooth eyepiece adjustment 
  • Well balanced in the hand 
  • Durable rubber grip 
  • Replaceable prism flap 
  • IP65 water resistant 
  • No need to replace batteries 
  • Open to user interpretation 
  • Less accurate 
  • Limited range 
  • Additional cost of purchasing multiple refractometers to cover multiple ranges 

Calibration and Verification

When it comes to purchasing a new piece of equipment, it is always worth considering the calibration or verification process. Optical refractometers don’t need to be calibrated. On the one hand, this could be seen as an opportunity to save money. On the other, it could be another limitation, as instead of having the option to adjust an optical unit, as you would a digital refractometer, it will either be functioning or void. What’s more, its prism flap is the only replaceable part. In contrast, the digital refractometer can be calibrated – a service provided by Klipspringer’s in-house lab.

We have also launched a series of calibration materials that allow you to carry out at least some of your calibrations remotely. In addition to this, we now stock a range of solutions that give you the option of validating your refractometers on site.

Access our Calibration Services

In Conclusion

That brings us to the end of our honest comparison of optical and digital refractometers. When it comes to evaluating the pros and cons of each option, the most important thing is that you prioritise the specific requirements of your factory. After, all nobody understands your site better than you! However, we do hope this overview has been a useful resource – helping you to evaluate the risks and applications associated with either purchase.  

With around 22 years of experience supporting over 4,000 food and beverage sites across the UK and Ireland, we are always happy to share our honest feedback and findings, determined to assist you in making the best decision for you and your site.

Both ranges are available to view and purchase online at, and if you require further support with your refractometers, don’t hesitate to contact the Klipspringer team!

Need support with your refractometer requirements?

Reach out to the Klipspringer team on 01473 461 800 or via our Contact page.