Choosing the right method for moisture determination can be difficult and there is no clear answer to this question. There are, however, a number of factors that can help you determine the best measurement method for your process:
First of all, ask yourself why it is important for you to measure moisture in food products.
Do you particularly want to improve the quality of your product or keep it at a desired high level? Or are you mainly interested in a more efficient drying process, where you save energy and increase productivity? What you want to achieve is an important factor in determining the best measurement method for your organization. Incidentally, the choice for an inline moisture analyzer often leads to gains in more than one area.
N.B. Many producers of animal feed dry in the open air. The efficiency of a drying process is therefore dependent on the outside air and not constant, making an in-line moisture analyzer indispensable for optimizing the drying process. Ask our product managers for the most suitable moisture analyzers for your process.
A second consideration that you must make is how quickly you want results.
The Karl Fischer Titration and Loss on Drying are methods that are applied in the laboratory and last considerably longer. With the Karl Fischer Titration it is important to get your product into solution. For solids such as candy, wheat, biscuits, dough and for example rice this can cause difficulties. In addition, it is important that chemical analysts are present in the house to perform the measurements. With the LOD method, volatile components such as alcohol or fat that evaporate just like water are also measured as moisture. The first two methods are destructive to the sample that you use. If you wish to adjust the process immediately, you opt for an in-line measurement. Only the Near-Infrared and Microwave Resonance methods can be used in-line in the process for moisture analysis. You can link the moisture analyzer directly to your process automation. If the moisture content threatens to go beyond specifications, you can immediately change numerous process parameters. Your process is thus better under control, which ensures savings through less waste or lower energy consumption, but also for better and more consistent product quality.
A trade-off is also the shape of your product. In coffee beans, for example, it is easy to imagine that the moisture content in the core of the bean is higher than on the outside. The penetration depth of Near-Infrared is often insufficient. Near-infrared analyzers could therefore be less reliable in such a case. Microwaves penetrate the matter many times deeper, up to a few centimeters, and therefore give a more representative result with a moisture gradient. Another consideration is whether you also want to measure other parameters than just moisture; then NIR (with the right shape) can be a better choice for you.
A final consideration that influences the choice of a method is the amount of moisture present in the product.
The dynamic measuring range of the moisture analyzer must match the specifications of your product. Moisture measurements are ideally done with the raw materials at the beginning of the process, before and after the drying step and at the end of the process. However, depending on your process installations, it is sufficient to measure the moisture content immediately after the drying process. The temperature of your product also plays a role here. Higher temperatures can negatively influence the reliability of the measurements.