Refractometers – Buying guide & Comparison
If you’re short on time and you just want to find the best refractometer, this short paragraph should help you get exactly the model you need. We have been able to collect plenty of information about the best product in this category by going over numerous best refractometer reviews and comparing the reviews and ratings there with what is in actual owner feedback. According to our findings/research, the Ade Advanced Optics RF15 is the best because of its superb accuracy level to +/- 0.20% Brix that ensures error-free readings every time. Boasting a sturdy design, this refractometer is made of tough machined aluminum that ensures chipping- and corrosion-free performance unlike flimsy ‘carbon’ plastic that can easily break or get damaged. This device also features Automatic Temperature Compensation (ATC) to provide consistent results without the need to bring the test sample to room temperature first before doing any measurements. This also eliminates the need for a refractometer chart that you need to constantly refer to with variations in measuring temperature. Shipped to you with its own clear case, this model is a handy tool for testing veggies and fruits, grasses, beer and wine, and also for the maintenance of CNC Coolants such as semi-synthetics, soluble oils, synthetics and neo-synthetics, as well as water-soluble drawing and stamping compounds. If the Ade Advanced Optics RF15 is unavailable, your second option should be the Agriculture Solutions SSA0010.
The ordinary man on the street may not have use for a refractometer, but a veterinarian, lab technician, gemologist, marine biologist, or even wine grape growers, homebrewers, beekeepers and those who own an aquarium will surely benefit from keeping this type of device handy. This field or laboratory device measures the index of refraction of a sample solution. What distinguishes the best refractometer from a run-of-the-mill device?
A suitable type for your needs
A refractometer can be one of different types. It can be a standard handheld refractometer, a digital handheld refractometer, an Abbe or laboratory refractometer, and an inline process refractometer. For the measurement of the refractive indices of different gases, a Rayleigh refractometer is typically used. There are also automatic refractometers that measure a sample’s refractive index automatically, which is done based on the determination of the critical angle of total reflection.
A traditional or standard handheld refractometer is an analog device that measures the refractive index of a sample liquid. It employs the critical angle principle that governs the way a lens or prism projects a shadow line onto a small reticle made of glass located inside the refractometer. The shadow line is then viewed through a magnifying eyepiece. The sample is placed between the small cover plate and measuring prism. The light channeled through the test sample is either totally reflected internally or passed directly to the reticle. The reading is taken where a shadow line forms between the lighted and dark area and crosses the scale. You will want a handheld model to have automatic temperature compensation because refractive index is highly temperature dependent.
A digital handheld refractometer operates like a traditional handheld one by utilizing the critical angle principle. The difference lies in the way a LED light source focuses light on a prism component or the underside instead of being channeled through a reticle or being totally internally reflected.
A digital handheld refractometer may be more precise than a traditional handheld model but may be less precise compared to a benchtop unit. A relatively large quantity of sample solution may also be required because it will not be spread thinly against the refractometer prism. Various units of measurement may be used to display the result and they include Brix, concentration, boiling point, Plato units or specific gravity, freezing point and others. The refractometer that a brewer would use is the same type that a fruit grower also uses to measure the concentration of sugar in their harvest to see if the fruits are ripe enough. This is called a Brix refractometer, and it measures 0 to 30 Brix or 1.000 to 1.120 specific gravity, which is a very useful range for home brewing purposes. For just such a purpose, steer clear of models containing electronic components or that measure battery acid or some other chemical substance. Refractometers that measure battery acid or other chemical solutions will require the use of available equations for conversion to Brix, aside from likely measuring the incorrect range of refractive indices. Brix refractometers measure the concentration of sucrose in a water and sucrose mixture to find the index of refraction of the sample being tested. Refractometers in the automobile maintenance industry measure the concentration of coolant and the pH value of the coolant oils used in the CNC machining process. Most models come with a sample well made of metal, which is positioned around the prism so it will be easy to clean off a sticky sample such as honey.
An Abbe refractometer is a benchtop instrument that offers high-precision measurement of the index of refraction. The liquid sample is placed into a thin layer sandwiched between a refracting and an illuminating prism. Projected through the illuminating prism is the light source, and a detector mounted on the refracting prism back side shows a dark and light region.
An inline process refractometer is geared for the continuous measurement of a fluid flowing inside a tank or through a pipe. This type of instrument comprises a sensor mounted inline with the flow of fluid and connected to a control box, which typically provides a digital readout along with relay outputs for controlling valves and pumps and 4-20mA analog outputs. The sensor is not placed inline of the process but in a bypass linked by a thin tube.
Useful features for measurement
Automatic Temperature Compensation (ATC) proves to be useful but not a strict necessity if you own a temperature compensation chart. Models that don’t feature ATC will require the temperature compensation to be optically performed and not just as an electronic effect. A good cheap refractometer will still provide an accurate reading despite the absence of ATC since only the instrument’s temperature is important because you will only need a small quantity of sample compared to the mass of the device itself. That being said, premium quality refractometers use ATC as a selling point to enable them to report the same value across a wide range of practical temperatures, generally between 13 and 29 degrees Celsius or 55 and 85 degrees Fahrenheit. ATC becomes a worthy feature to have in your device as a couple of drops of even boiling wort can cool quickly to within that range, giving all-grain brewers a specific advantage for monitoring the runoff gravity typically around 170 degrees Fahrenheit. ATC enables you to use the reading you obtain.
The best digital refractometer comes with software to avoid reading interferences due to excessive ambient light. Shading the prism area prevents interference as well. Some models come with dual or multiples scales. They have the capability of inputting a special scale using conversion information that is known. Some digital handheld units are IP65 rated to signify they are water resistant, so you can wash them under running water.
Easy to calibrate and use
Compared to a hygrometer that simply floats in the solution you’re testing, a refractometer is really not as simple to use. The refractometer makes it tricky to calculate the final gravity adjustment. It pays to know what you’re getting when you buy a refractometer. You will also need to calibrate the refractometer prior to use. Fortunately, calibrating most refractometers is simply done using a sample of distilled water. Most units also come with a calibration screw or knob that enables setting to zero. This is what you will need to do: adjust the refractometer to zero while distilled water is in it. You may need to make a few tries to succeed in this process. For precise readings, you also need to calibrate the device using a wort sample with known specific gravity.
To test a sample, all you need to do is open the sample plate, ensure it is clean and dry, and add a few drops of the test solution. Close the sample plate, making sure there aren’t any air bubbles, and then hold up the instrument against a natural light source. It should be easy to read the instrument as well simply by reading straight from the sight scale, with the reading most often in percent/degrees Brix or refractive index (RI).
Top refractometer reviews in 2017
There are plenty of options on refractometers on the market. Although this can somewhat complicate the shopping process, we have designed the above buying guide to provide helpful information and tips for spotting the best product for sale. We have also showcased the best products below for more help.
Ade Advanced Optics RF15 RHB-32ATC
If you’re looking for the best auto refractometer, the Ade Advanced Optics RF15 is just the right one for you. Providing accuracy to +/- 0.20% Brix, this instrument offers a 0 to 32% Brix scale to read a variety of samples easily. It comes with Automatic Temperature Compensation feature so you won’t have to bring your sample to room temperature first prior to measuring the refractive index.
You can place the sample straight on the sample plate and take the reading right there. Boasting a rigid design, this device is made of durable machined aluminum and not thin ‘carbon’ plastic, ensuring years of use without being prone to chipping and corrosion.
Ideal for testing vegetables, fruits and grasses, the RHB-32ATC comes in a clear case for problem-free carrying in the pocket or gear box while ensuring easy storage and protection for the sensitive measuring components of the instrument.
This also makes a handy device to use in wine or beer making and for the maintenance of CNC Coolants such as synthetics, neo-synthetics, semi-synthetics and soluble oils, along with water-soluble drawing and stamping compounds. Use this refractometer to ensure quality control in your manufactured products and harvests to keep your customers satisfied with your offerings consistently.
Buy from Amazon.com for ($22.99)
Agriculture Solutions SSA0010
Easily the best refractometer for saltwater aquarium, the Agriculture Solutions Dual Scale can be used to test the salinity plus specific gravity of water. Equipped with a dual scale, this instrument measures on two scales: parts per thousand (%) and specific gravity (D20/20), with a range from 0 to 100 and 1.000 to 1.070, respectively.
Designed for aquariums and marine monitoring, this device comes with Automatic Temperature Compensation so you can simply take some sample solution and drop the liquid into the sample well fornstraightwaway testing and reading. The instrument ships with a hard case, dropper, screwdriver and cleaning cloth so you have everything you need right out of the box.
This device makes the perfect replacement to your poor quality refractometer. It offers easy viewing and reading of values and will only need a couple of drops of aquarium water to let you know the exact level of salinity.
This ensures that your pets are safe in your aquarium and that the water they are swimming in has the exact level of salinity they need to survive and thrive in their typical marine environment. Calibrating can be done by testing distilled water and using the supplied screwdriver to set to Zero. The stainless steel screw for calibration ensures years of use with its resistance to corrosion and chipping. The all-metal head and metal ring ensure a sturdy design.
Buy from Amazon.com for ($20.93)
ETvalley Beer Wort and Wine
The ETvalley Beer Wort and Wine model is definitely the best budget refractometer thanks to its affordable price. However, it does not scrimp on top notch features. It comes with a dual scale so you can read whichever is suitable to your specific needs.
Made with an aircraft-quality lightweight aluminum body, this is a durable device that can withstand chipping and corrosion to provide years of service. It also comes with Automatic Temperature Compensation (ATC) feature to enable you to do direct readings without having to bring the sample solution to room temperature first, which saves you time and effort while still ensuring precise measurements.
Furthermore, this model is the best honey refractometer, proving to be highly useful for beekeeping where it is necessary to measure the amount of water in the honey that is produced. The non-slip rubber handle works for easy holding in the hand.
The premium optical lens is supplemented with a rubber eye guard to ensure easy viewing through the lens. Easier to use than a hydrometer, this device proves to be more accurate for the measurement of sugars. After use, the device stores easily in its own convenient carrying case. This tool also comes with everything else you need for successful measuring right out of the package: Pipette; Mini screwdriver for calibration; Cleaning cloth; and instruction manual.
Buy from Amazon.com for ($30.99)
Brew Tapper BT-DS-REFRACT
By its name alone, you’ll know that the Brew Tapper BT-DS-REFRACT is inarguably the best refractometer for brewing. It comes with its own plastic case for problem-free storage and protection for the sensitive measuring components while facilitating effortless transport and carrying.
The included calibration screwdriver facilitates periodic calibration to ensure consistently accurate measurements every time. The 3ml pipette enables easy taking of sample solution and dropping onto the sample plate. The lens cleaning cloth ensures that the eyepiece and cover are clean after use. Made of aluminum, this refractometer is built to withstand chipping and corrosion for years of reliable service.
Use this handy device to measure the specific gravity before fermentation if you are a homebrewer. It enables you to determine the amount of fermentable sugars that can be potentially converted to alcohol so you can maintain the quality of your brew.
This device lets you take control of your brewing process with your own quality control assurance testing. You can make your own homemade beverages by upgrading your trusty old hydrometer with this precise instrument, which ensures that homemade wines, beer, fruit juices and your other homemade beverages maintain your preferred quality at all times. With its Automatic Temperature Compensation feature, the device can account for ambient temperature changes on its own so you won’t need to bring the solution to room temperature first prior to testing, saving you time and effort.
Buy from Amazon.com for ($28.99)
Magnum Media Salinity 10ATC 5546
If you want the best cheap refractometer on the market, the Magnum Media Salinity 10ATC 5546 should be the first on your shopping list. This impressive product boasts Automatic Temperature Compensation feature so you can save time and effort during measuring processes.
You won’t need to wait for your sample solution to come to room temperature before taking a reading. You can take readings outdoors also even when the temperature is between 50 degrees fahrenheit and 86 degrees fahrenheit or 10 degrees celsius to 30 degrees celsius. Replacing your less reliable hydrometer, this device measures salinity using two scales: specific gravity and percent. It has a range of 0 to 100 percent/degrees and 1.000 to 1.070 Salinity SG.
This seawater refractometer comes in its own hard case to ensure protection for its sensitive measuring elements and to facilitate easy transport and efficient storage. Calibration is easy using a 35 ppt salinity standard or plain distilled water, ensuring consistent accuracy in readings every time.
All you need for reading is strong light including natural daylight, whether in sunny or cloudy weather, as well as a flashlight or lamp. Lightweight at just 9.6 ounces, this tool measures 8.1 x 3.2 x 1.7 inches for easy holding in the hand. The textured handle ensures easy and secure gripping while the eyecup ensures easy focus on the eyepiece.
Buy from Amazon.com for ($19.98)