This Guide Is Not Just for One Brand of Refractometer

Although National Industrial Supply sells and services a wide variety of handheld clinical and veterinary refractometers, the basic operating principles covered in this guide apply to many brands and models of optical veterinary refractometers.

Whether your instrument is a MISCO, Atago, Reichert, Heska, Westover, JORVET, American Optical, Schmidt + Haensch, or another manufacturer, you will generally encounter the same fundamental concepts: properly calibrating the instrument, focusing the optical system, applying an adequate sample, selecting the correct species-specific scale, interpreting the light/dark boundary, and cleaning the prism between measurements.

There can be important differences between manufacturers and individual models, particularly regarding calibration procedures, temperature compensation, available scales, cleaning instructions, sample volume, and acceptable operating temperatures. Your manufacturer's instructions should always take precedence when they differ from the general procedures described here.

The reason we created this guide is simple: we hear from veterinary technicians using refractometers from all kinds of manufacturers. Many of the questions are remarkably similar—"How do I calibrate this?" "Which line do I read?" "Why is my reading blurry?" "Do I need to clean it between samples?" "Why doesn't my water read 1.000?"

If you are holding a veterinary refractometer that is new to you, we hope this guide gives you the practical foundation you need to understand what the instrument is doing and how to get consistent readings from it.

In fact, published veterinary research has compared multiple refractometers—including American Optical, Reichert, Heska, MISCO, Atago, and other optical and digital instruments—showing why understanding both the instrument and the measurement technique is important. Different instruments can produce somewhat different readings, even though several commonly used veterinary refractometers have demonstrated strong agreement for canine urine specific gravity. PubMed

So if you didn't purchase your refractometer from National Industrial Supply, that's perfectly fine. This information can still help you learn how to use it. Our objective is to make the process less intimidating and help veterinary professionals get the most reliable measurement possible from the instrument they have in front of them.

MDEA + Piperazine Refractometer Calibration: How to Create a Custom Scale for Your PA202X-592

When a refractometer is used to measure an industrial chemical solution, one question comes up again and again:

Can I use a refractometer designed for one concentration or formulation to accurately measure my particular chemical mixture?

For many water-soluble industrial fluids, the answer is yes—but the important question is how the refractometer is calibrated for that specific fluid.

This becomes especially important with MDEA (N-methyldiethanolamine) solutions used for natural gas sweetening when piperazine (PZ) is added as an activator.

A customer may have a solution containing:

• 43.5% MDEA
• 6.5% piperazine
• 50.0% water

and discover that a standard MDEA refractometer scale does not appear to agree with the known concentration of the solution.

Measuring Invert Sugar with a Refractometer: Brix, Applications and Choosing the Right Instrument

Invert sugar is used throughout the food and beverage industry, particularly in applications where controlling sweetness, moisture, texture, shelf life and crystallization matters. From confectionery and baked goods to beverages, jams, syrups and pharmaceutical products, manufacturers need a practical way to monitor the concentration of sugar solutions during production.

One of the simplest analytical tools for this purpose is a refractometer.

Using a Refractometer to Test Kombucha, Beer, Wine, Mead and Other Low Alcohol Fermented Beverages

A refractometer can be a remarkably useful tool for monitoring kombucha, beer, wine, mead, cider and other fermented beverages. It is fast, requires only a small sample, and can provide useful information throughout the fermentation process.

But there is an important distinction that every brewer, fermenter and beverage producer should understand:

A refractometer measures refractive index. It does not directly measure sugar, alcohol or fermentation progress.

Before fermentation, Brix or specific gravity readings can provide a very useful indication of the starting concentration of dissolved solids. After fermentation begins, however, alcohol and organic acids change the optical properties of the liquid. That means a simple Brix-to-specific-gravity conversion can become misleading.

Used correctly, a refractometer is an excellent process-monitoring instrument. Used incorrectly, it can produce numbers that look precise but do not mean what the operator thinks they mean.

How to Test Fruits and Vegetables with a Brix Refractometer: A Complete Guide to Accurate %Brix Testing

Testing the %Brix of fruits and vegetables is one of the fastest ways to get useful information about the soluble solids present in plant material. Farmers, growers, produce buyers, food processors, researchers, winemakers, gardeners and agricultural professionals can use a Brix refractometer to compare samples, monitor crop development and establish consistent measurements from the field to the laboratory.

The instrument itself is relatively simple. A few drops of plant juice are placed on the prism, the daylight plate is closed, and the refractometer measures how the sample affects the passage of light through the prism.

The difficult part is often not taking the reading.

The difficult part is obtaining a representative, clean and repeatable sample.

Sample size, juice extraction, suspended particles, temperature, calibration, prism cleanliness and the condition of the produce can all affect the quality and repeatability of the measurement.