How to Use a Traditional Analog Handheld Refractometer

analog-refractometers

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.

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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.

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Beer (3)

Can your digital refractometer be used to determine balling (sugars) in distillers mash? The standard has been to use a balling hydrometer. Also would there be one to determine alcohol in the fermenting mash? The max is around 9% by volume.

Our Palm Abbe digital refractometer is ideal for measuring the sugar content of mash for beer makers. You can use either the Brix scale or the balling scale for this. Once fermentation begins a refractometer cannot be used to “directly’ measure either the sugar content or the ethanol content since they will interfere with each other. However, there are some indirect methods using the Brix scale to monitor fermentation.

We are a California manufacturer of a carbonated low-alcohol beverage and are looking for a relatively low-cost way to test samples to make sure alcohol is below 0.5%. Would your refractometer work for this?

Unless your beverage is just ethanol and water, a refractometer will not be able to directly measure the alcohol content. This is because sugars in the solution will conflict with a reading of alcohol and vice a versa. Probably the best way to test this is by distilling the beverage and measuring the distillate with a Palm Abbe digital refractometer equipped with an ethanol scale.

We use your Palm Abbe PA201 digital refractometer for making sorbet, and love it! But we’re confused as to how it operates on solutions that contain sugar and alcohol in combination: the readings don’t seem to make sense. Is there a way to compensate for this?

Unfortunately it is not possible to measure sugar contents and alcohol content in combination in a sorbet or other solution using a refractometer. Refractometers are very good at measuring binary solutions (two-part), such as water and sugar, where water is a constant and sugar is a variable. However, a refractometer is not very good for measuring multi-component solutions such as water, sugar, and alcohol. When there are several different components in a solution, such as water, sugar, and alcohol, it is difficult to tell what the contribution is that each component makes to the total refractive index. So, if the refractive index changes, it is impossible to say, with any certainty, which of the component parts changed. A refractometer only measures the total refractive index of a solution and cannot selectively read the refractive index of one particular component. All water soluble fluids look the same to the refractometer. So, depending on the concentrations of the other constituents, it may be difficult to get an accurate reading of any one component.