Moisture Measurement

Water content or residual moisture, for example in harvested crop from wheat to green feed, is a decisive quality parameter: When moisture levels are not regulated, products get moldy or face other threats that negatively affect their quality. Therefore, agri-business and the food industry are looking for non-destructive and fast ways of determining the water content in their products, and are permitting the integration of corresponding methods into external control systems. NIR spectroscopy meets their demands.

Measurement theory

NIR spectroscopy is a well-established technology for online moisture testing: A light source is collimated and filtered into specific wavelengths. Water displays the characteristic absorption at a near infrared range between 1,100 and 2,450 nm. The filters are chosen such that one wavelength will be absorbed by water (sample beam) and one wavelength will be unaffected by water (reference beam). In consequence, the amplitude ratio of the two reflected wavelengths will be proportionate to the amount of water in the product. This filtered beam is directed onto the surface of the sample to be measured. One part of the light is reflected back to a detector. Chemometrical methods then also allow the calculation of water contents in different matrices.

  • Analysis of all sorts of biological systems
  • Little or no sample preparation necessary
  • Non-destructive measurement method
  • Results emerge very fast within seconds
  • Universal application any molecule containing C­H, N­H, S­H or O­H bonds
  • Several analytical results can be predicted from the same NIR data
  • Simultaneous multi-component analysis without chemical or disposable costs
Examples of use
  • Ensures proper product handling during processing to avoid spoilage of grain by mold or fungi
  • Determines the types of grains best suited for a particular use or type of grinding
  • Evaluates whether processes like freeze-drying should be employed to preserve the grains