Examining Moisture Meter Methods: Karl Fischer and Near Infrared Technology

Posted by John Bogart on Thu, Mar 28, 2019

nir_moisture_meter_230In the world of obtaining accurate readings of moisture levels, there are several scientific, reliable ways to gather data. Some, like the Karl Fischer method, have weathered the test of time, with decades of use. Others, like the newer, flashier near infrared moisture meters, have found their place in the industry more recently, because they are so practical, easy, and time-efficient.

So what is the Karl Fischer method, and why should you consider switching to the newer, near infrared technology? Let’s take a look:

Karl Fischer

One way to gather information on moisture levels in various products is the Karl Fischer (KF) moisture measurement method. Named after the German chemist who developed the technique, this has been a popular and reliable way to determine moisture levels for decades.

Karl Fischer was born in Germany in 1901, and his passion for chemistry showed at an early age. From the time he was a boy, Fischer was conducting complicated scientific experiments in his bedroom, where he had set up a small laboratory. His passion for chemistry grew with him, and Fischer earned his doctorate at the University of Leipzig in 1925 and set his sights on a career in chemistry.

Karl Fischer made his mark by taking a process of chemical reaction developed nearly a century earlier by Robert Bunsen, and using it to measure trace amounts of water in order to obtain moisture levels.

Fischer’s Discovery

How did Fischer develop a system of measuring moisture levels decades ago that is still highly used today? The KF titration moisture technique focuses on creating a chemical reaction in the substance in order to determine levels of moisture. While this process was originally completed manually, it has now been automated, though the process is still time consuming and the equipment still bulky.

So how does it work? The sample is combined with chemical reagents in order to cause a chemical reaction to occur. During this chemical reaction, water is chemically separated from the rest of the sample, and moved into another chamber within the device, so that it can be weighed. This measurement is compared with the original mass or volume, to calculate the total moisture content of the sample. This process is very accurate providing a reading at the level of Parts Per Million (PPM).

Why is this method still used, after nearly a century, and with new technology on the market? Samples don’t have to be very large at all. It’s also a great way to measure moisture content in liquids, as it was first developed to determine moisture levels in oil. There’s no need for calibration.

Why do people use any other method besides the KF method, since it is so accurate and so versatile? For starters, it can take a very long time, and cost a great deal of money and manpower. The process can take as much as an hour, and since it requires a liquid sample, any solids have to be dissolved first. Also? It’s a fairly detailed process requiring a high degree of expertise. KF titration also is a destructive test, meaning that any sample acquired is destroyed during the testing process. Lastly, the chemical reagents needed to perform tests can be rather costly, making the process cost prohibitive for some.

Near Infrared Technology 

In the years since Fischer’s studies, technology has exploded, and new developments have arrived in the field of calculating moisture levels. One of the “bright stars” in the field is the use of near infrared (NIR) technology. NIR moisture meters measure the absorbance and reflectance of light to determine the moisture levels: The more light that is absorbed, the higher the moisture content.

The light is filtered into a wavelength, or in some cases, multiple wavelengths. The light that is reflected back to the device is converted using an algorithm to provide an accurate reading. It’s so fast, flashy, and accurate that it seems like something out of your favorite science fiction TV program.

The use of NIR moisture meters is widespread, appearing in the food processing and packaging industries as well as tobacco, paper and packaging, pharmaceuticals and chemicals, and textiles. No matter the industry, there’s a use for NIR technology.

Why NIR Moisture Meters are the Way to Go

Why have so many chosen to take advantage of this new NIR technology? For starters, results are nearly instantaneous. Gone are the days of waiting for results in the field with quick readings. Additionally? NIR moisture meters are non-destructive and non-contact, so you never lose your initial sample. They are versatile, working in many conditions and with both solids and liquids, and are available in handheld, in-line, and desktop versions for even more versatility, catering to your needs. Unlike the somewhat clunky Karl Fischer system, these devices are streamlined, and can be easy to transport and use, no matter the location.

The NIR moisture meters of today can also measure surface moisture on packaging to prevent issues with packaged foods, and with slight adjustments can also measure levels of other substances, like fats and oils, sugar, and fiber.

While they do require some initial calibration, NIR moisture meters are easy to use and cut the wait time to nearly nothing.

Ready to make the switch to the fast-paced, easy-to-use, and high tech world of NIR moisture meters? Let Kett help you with the change. Contact us today to ask questions or get more information about how a NIR moisture meter can make all the difference in how to collect and analyze moisture data.

Subscribe by Email