Digital Dip Style Refractometer:
How to use Digital Dip Style Refractometer:
Dip refractometer into liquid, press start and read results within 3 seconds.
Review of Digital Dip Style Refractometer:
This is the newest and simplest way that allows for technology, design and user interface to excel to the highest level. The digital display is easy to read and understand. It has a prism that is located at the tip of the refractometer to allow for quick and easy sampling. Instead of taking only a few drops of the sample(s) you instead dip the prism directly into the fluid which greatly minimizes user error. By design, the prism is easy to clean addressing the refractometer’s false results due to poor cleaning. Unlike, the well style, the prism is not recessed but is in-fact flush mounted in the stainless steel head. This mounting prevents diluting the sample with previous sample, or water left over from cleaning. The digital dip style refractometer is designed for intuitive use and easy maintenance and inspection.
Digital Well Style Refractometer:
How to use Digital Well Style Refractometer:
Use a pipette to sample the desired liquid. Drip the sample onto the prism and close cover. Select the proper scale, press start and read results.
Review of Digital Well Style Refractometer:
This is a newer style refractometer but is not a fool proof method of testing samples. Comparable in price with a dip-style, it uses a well-style testing area. This design feature requires each liquid to be sampled with a pipette and be dripped into the well-like testing area. The results are digitally displayed and typically are easy to read and understand. You can easily tell a well style due to its design with a recessed prism that resides at the bottom of a stainless steel “bowl or well”. Both the optical and well style digital refractometers require the user to sample via a typical pipet and must bring the sample(s) to the refractometer. This involves some time and has been documented to cause considerable user errors. The well-styles refractometer typically requires a very small amount of fluid sample, approx. 1 to 3 droplets of the sample taken. Some designs include a cover to shield the sample from surrounding light, that can affect the results. It is important to note that the device’s accuracy is quite high, but there is a high likelihood of false positive/negative results due to user error. The most common causes of incorrect results are: too many/too few droplets of sample being tested, retained residue on the recessed prism from proteins and butterfat, tiny water droplet residue diluting the sample, a reused pipette that mixes previous sample or a pipette with water residue diluting the sample.
How to use Optical Refractometer:
Use a pipette to sample the desired liquid. Drip the sample onto the prism and close cover, make sure the entire surface is covered and there are no air-bubbles. Let the sample sit for 30sec-2min, then point the refractometer at a light source (sunlight or bright light-bulb), look through the eye piece and read results at the demarcation line where blue and white meets.
Review of Optical Refractometer:
This is a very basic and “old school” method of refractometry. It does not need batteries to test, but the caveat is it works best in full sunlight or an extremely bright light bulb in order to read the results. During application of a sample onto the large prism you must ensure full coverage. Once the plastic shield has been lowered and placed onto the sample, ensure that there are no gaps or air bubbles on the prism. Those would directly affect the accuracy of the results observed. To read the results of an optical refractometer, look through the eye piece at the intersection line of the blue and white color, which is called the “contrast line”. Sometimes, it may be very hard to distinguish the line and determine the actual quality of the sample. The longer you can wait before reading the scale results, the more time the prism has to better establish a defined demarcation line (this can be from 30 seconds to a couple of minutes).
The optical refractometer is the least costly of the three types, but you are more likely to have false positives and false negatives with this technology due to design and user error.