How to Use a Traditional Analog Handheld Refractometer


Different models of traditional analog refractometers have different internal scales on which to read fluid concentrations. Some instruments have specialized scales that indicate the exact mixture of the sample being tested, while others have an arbitrary unit of measure that works like a shorthand for refractive index measurements.

The instruction manual that comes with each refractometer carefully explains the procedure for comparing refractometer readings to the actual known concentrations or properties of your specific fluid. Trained MISCO technical support engineers are always available to assist you at any time.

How to Take a Reading With a Traditional Analog Refractometer

MISCO refractometers are easy-to-use and require little or no training. They can be mastered by ANYONE in just minutes.

  1. Place a drop of sample on the measuring surface beneath the ViewPoint Illuminator.
  2. Look through eyepiece and press the ViewPoint Illuminator.
  3. Take your reading at the point where the contrast line (difference between light and dark areas) crosses the scale.


How a Traditional Analog Refractometer Works

Light passing through a liquid is slowed compared to the speed it travels in air. So once a fluid sample is placed on the measuring surface of a refractometer, the light passing through it slows and is bent.

The refractometer focuses this bent light on a tiny internal scale. The scale is magnified by the eyepiece lenses so it is easily visible.

The optics are supported by a bi-metal strip that moves lenses in response to temperature changes, ensuring that readings are accurate regardless of temperature.



Wine (4)

Hi, I just bought the Palm Abbe refractometer with 5 scales from you. I have tried it at our office but I cannot get it come to the right results. We are only going to measure total sugar content and alcohol in wines (finished wines). I have calibrated it with distilled water and it seems to measure water to 0.0 every time which is ok. As soon as i measure alcohol in red wine it always shows too high digits – up to 18-20% ABV and the sugar is always too high. What may the problem be in this case?

The problem is that you cannot directly measure the alcohol content in finished wine using a refractometer. Once fermentation begins ethanol and the residual sugar interfere with each other and prevent an accurate reading of either sugar content or alcohol content. The best method for determining the alcohol content in the wine is distillation. There are also some good methods of estimating alcohol and sugar content during fermentation and later in the finished wine. For more information, download a copy of our free guide, “Using Refractometers to Increase the Efficiency of Vineyard Management and Winemaking “Using Refractometers to Increase the Efficiency of Vineyard Management and Winemaking.”

We are a small winery on premise in Michigan and we make our wines from Must and kits only, we don’t crush the grapes. Is there a refractometer you could recommend for our purposes which could tell us actual specific gravity and Actual Alcohol readings of finished wine?

A refractometer is very useful at nearly all stages of wine production. It can be used to help assess the ripeness of grapes before harvest, predict alcohol content from the must, measure the sugar content of must, monitor the fermentation process, and determine the alcohol by volume (ABV) of the finished wine. A refractometer with the Brix scale is the best method of determining the sugar concentration of the grapes and must. Scales are available that can predict the alcohol content of the finished wine based on must measurements. Once fermentation begins ethanol will interfere with sugar readings and you will not be able to take direct readings of either alcohol content or sugar content, without using special techniques. Once the wine is finished, the same refractometer, with an ethanol scale, can be used to measure the distillate of the wine to accurately determine alcohol content.
Click the following link to download a copy of our technical bulletin on “Using Refractometers to Increase the Efficiency of Vineyard Management and Winemaking.”

I am interested in the VIN06 refractometer for the determination of alcohol in fortified wines. What is the process for determining the alcohol – it appears you have to distil the wine before measuring it with the refractometer. How would I do this?

You cannot directly measure the alcohol content in a finished wine with a refractometer. However, you can distil the wine and then use the alcohol scale on the Palm Abbe digital refractometer to measure the ethanol content of the distillate. More information can be found in our technical bulletin  “Using Refractometers to Increase the Efficiency of Vineyard Management and Winemaking.

How accurate is your refractometer when alcohol is present? Can I measure R.S. [residual sugar] in wine? thanks

Alcohol and sugar interferes with each other when measuring finished wine with a refractometer. You cannot measure the alcohol content in a finished wine directly using a refractometer, nor can you directly measure the residual sugar content. There are however, a couple of tricks that you can use to determine alcohol content and residual sugar content using a refractometer. These methods and more are discussed in detail in our technical bulletin, “Using Refractometers to Increase the Efficiency of Vineyard Management and Winemaking.