Cop­per Chlor­ide Crys­tal­lisa­tion GESTE 3 (Gestalt Eval­u­ation and Struc­tural Eval­u­ation III) (2016 - 2022)

The cop­per chlor­ide crys­tal­lisa­tion method

In recent literature on the assessment of food quality, the matrix, i.e. the structure in which the ingredients are incorporated, is becoming increasingly important. The copper chloride crystallisation method provides information on properties of the matrix/structure of the food by examining the ageing resistance of the whole food.

In copper chloride crystallisation, an aqueous copper chloride dihydrate solution with added plant extract crystallises in the form of juice or extract (Busscher et al. 2010). Spontaneous crystallisation in the form of needles occurs when the saturation limit of the salt solution is exceeded during the phase of evaporation of the liquid. The resulting crystal images are evaluated either with a computer-assisted texture and structure analysis (Andersen et al. 1999, Doesburg and Nierop 2013) or visually (Huber et al. 2010, Doesburg et al. 2015,). Visual evaluation allows conclusions to be drawn about the ageing resistance of the food under investigation by comparing it with reference images of different ageing stages of the food extract (e.g. Fritz et al. 2011, 2017, 2020). A number of coded samples from different cultivation trials were investigated, always showing a higher ageing resistance of organically vs. conventionally grown wheat (Fritz et al. 2011, 2018), grapes (Fritz et al. 2017, 2020), apples (Weibel et al. 2000) and beetroot (Mäder et al. 1993). The GESTE consortium is an expert panel that has documented the methodological principles of visual evaluation of copper chloride crystal images since 2013 and was then trained on these defined criteria. The panel evaluates the ageing resistance of samples from different backgrounds (e.g. fertilisation, cropping systems, varieties, processing: Doesburg et al. 2015, 2021, Fritz et al. 2018).

Pro­ject goal

The Geste group is a consortium of 8 researchers from 4 laboratories, which further develops the visual evaluation of the copper chloride crystallisation method.


2016 – 2022


Par­ti­cipants at FÖL

Other par­ti­cip­at­ing re­search in­sti­tutes

Hiscia, Association for Cancer Research

  • Dr. Claudia Scherr
  • Paul Doesburg

Research Ring e.V.

  • Dr. Uwe Geier
  • Roya Bornhütter

Section of Organic Food Quality and Food Culture, University of Kassel

  • Dr. Nicolaas Busscher
  • Gaby Mergardt


Software AG Foundation


BMEL (Federal Ministry of Food and Agriculture)

BÖLN (Federal Scheme for Organic Farming and Other Forms of Sustainable Agriculture)


Andersen, J.-O., Henriksen, C. B., Laursen, J. & Nielsen, A. A., 1999. Computerised image analysis of biocrystallograms originating from agricultural products. Computers and Electronics in Agriculture 22, 51-69

Busscher, N., Kahl, J., Doesburg, P., Mergardt, G. & Ploeger, A., 2010a. Evaporation influences on the crystallization of an aqueous dihydrate cupric chloride solution with additives. Journal of Colloid and Interface Science 344, 556-562

Doesburg, P. & Nierop, A. F., 2013. Development of a structure analysis algorithm on structures from CuCl2.2H2O crystallization with agricultural products. Computers and Electronics in Agriculture 90, 63-67

Doesburg, P., Fritz, J., Athmann, M., Bornhütter, R., Busscher, N., Geier, U., Mergardt, G., Scherr, C., 2021. Kinesthetic engagement in Gestalt evaluation outscores analytical ‘atomic feature’ evaluation in perceiving aging in crystallization images of agricultural products.  PLoS ONE, 16(3), e0248124.

Doesburg, P., Huber, M., Andersen, J.-O., Athmann, M., van der Bie, G., Fritz, J., Geier, U., Hoekman, J., Kahl, J., Mergardt, G. & Busscher, N., 2015. Standardization and performance of a visual Gestalt evaluation of biocrystallization patterns reflecting ripening and decomposition processes in food samples. Biological Agriculture & Horticulture 31, 128-145

Fritz, J., Athmann, M., Andersen, J.-O., Doesburg, P., Geier, U. & Mergardt, G., 2018. Advanced panel training on visual Gestalt evaluation of biocrystallization images: ranking wheat samples from different extract decomposition stages and different production systems. Biological Agriculture & Horticulture 0, 1-12

Fritz, J., Athmann, M., Kautz, T. & Köpke, U., 2011. Grouping and classification of wheat from organic and conventional production systems by combining three image forming methods. Biological Agriculture & Horticulture 27, 320-336

Fritz, J., Athmann, M., Meissner, G., Kauer, R. & Köpke, U., 2017. Quality characterisation via image forming methods differentiates grape juice produced from integrated, organic or biodynamic vineyards in the first year after conversion. Biological Agriculture & Horticulture 33, 195-213

Fritz, J., Athmann, M., Meissner, G., Kauer, R., Schultz, H.R., 2020. Quality assessment of grape juice from integrated, organic and biodynamic viticulture using image forming methods. OENO one,

Huber, M., Andersen, J.-O., Kahl, J., Busscher, N., Doesburg, P., Mergardt, G., Kretschmer, S., Zalecka, A., Meelursarn, A., Ploeger, A., Nierop, D., van de Vijver, L. & Baars, E., 2010. Standardization and Validation of the Visual Evaluation of Biocrystallizations. Biological Agriculture & Horticulture 27, 25-40

Mäder, P., Pfiffner, L., Niggli, U., Velimirov, A., Boltzmann, L., Balzer, U., Balzer, F. & Besson, J.-M., 1993. Effect of three farming systems (bio-dynamic, bio-organic, conventional) on yield and quality of beetroot (Beta Vulgaris L .var esculenta L.) in a seven year crop rotation. Acta Horticulturae 339, 11-31.

Weibel, F. P., Bickel, R., Leuthold, S. & Alföldi, T., 2000. Are organically grown apple tastier and healthier? A comparative field study using conventional and alternative methods to measure fruit quality. Acta Horticulturae 517, 417-427