Benchtop NMR in winemaking

In winegrowers' cooperatives and wineries, reliable and rapid analysis of incoming batches of grapes is essential today. Ideally, a sample is taken from the grape or mash container before unloading and analyzed for sugar and acid content as well as rot indicators using Fourier transform mid-infrared (FT-IR) spectroscopy. If the measurements indicate that the degree of rot in the grapes is too high, this can lead to deductions in the payment or even the rejection of entire batches of grapes. At the same time, the values provide important information for further winemaking. A major disadvantage of the established FT-IR spectroscopy is the indirect measurement method, in which FT-IR spectra are correlated with the reference analysis using a statistical model. This often leads to incorrect results. Nuclear magnetic resonance (NMR) analysis offers many advantages in this respect, as it measures the chemical species directly without the need for special sample preparation. It therefore provides very reliable quantitative results without the need for complex specific calibration in the relevant matrix such as must and wine. Until now, however, there has been a lack of inexpensive NMR measuring devices that can be used for mobile wine analysis. For some years now, compact benchtop NMR spectrometers have been available that meet these criteria.