Rapid sulphur-dioxide test approved for winemaking

Rapid sulphur-dioxide test approved for winemaking
By Richard Mills,
WineScan SO2 has been approved as a method for the official final analysis of wines in Germany. Further to this approval, positive results from a ring test by top German wine laboratories and a similar study by FOSS gives yet more indication of the reliability of the WineScan against standard methods. One main difference remains though. The WineScan is much faster.

Launched in 2012, the WineScan SO2 offers a new rapid way to measure free and total SO2 much more quickly than with traditional methods while simultaneously testing for a raft of other parameters in grape must and wine. 


Since the launch of WineScan SO2, FOSS has worked to get an approval to use the new WineScan method to evaluate wines in Germany’s AP number system. In the AP system, the wine must pass a set of analysis test to get a unique AP number from the state governments. Wine without an AP number cannot be sold on the German market. 


Official approval procedure

To get the approval, the performance of the WineScan SO2 was tested and documented in two ring tests involving eight wine laboratories. It was approved first by Germany’s leading wine producing state of Rhineland-Palatia, leading the way for recognition by all the wine producing states of Germany.


Follow-up ring test comparing WineScan with traditional methods

Further confirmation of the WineScan method comes from a ring-test comparing the WineScan SO2 against standard reference methods for testing SO2. This ring-test was conducted in 2014 by 13 top wine laboratories in Germany to check the reproducibility of the method and the consistency of results against standard reference methods. A positive conclusion was made.


A total of 22 different types of wine of varying quality and from different regions were tested. The levels of Free SO2 in the wines ranged from 10 mg/L to more than 60 mg/L and for Total SO2, the level was between 50 mg/L and 260 mg/L.


Own study by FOSS indicates correlation against reference methods

The most common reference methods are Colourimetric, Aeration/Oxidation and Iodine/Iodate titration. All the methods have their pro’s and con’s regarding precision, specificity and automation. The differences in results can sometimes be significant depending on methods, wine types and content level.


Some differences will be seen between the new WineScan method and the standard reference methods. However, comparison tests conducted by FOSS show a high correlation between WineScan results and methods such as Iodine/Iodate titration and aeration/oxidation (OIV). 


Rapid sulphur-dioxide test approved for winemaking

A number of samples have been measured in parallel by multiple reference methods. The results of the comparison against WineScan SO2 predictions is indicated in this graph.


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