A method for the determination of the water-uptake capacity of powders which is said to be applicable to viscose silk, specific celluloses, soap, paint, glue, gelatine, adhesives based on starch, biological samples, and soils, was proposed by Enslin in 1933 and has been improved several times since then. Today in Germany, the so-called Enslin-Neff method is used by the clay industry, in civil engineering, and in soil science. Many authors have identified the influence of evaporation on the results obtained using this method and the latest modification of the Enslin-Neff method was introduced by Dieng in 2005 where a balance was used instead of a burette to record the water-uptake capacity. It is proved here that the Dieng method actually operates correctly, independent of relative humidity. Therefore, a significantly improved reproducibility of the Dieng method compared to the traditional method was expected. However, it was found that the Dieng apparatus has specific sources of error (e.g. constance of the balance over 24 h) and varying the relative humidity no longer has a systematic affect on the results.
The reproducibility of the traditional Enslin-Neff method is strongly influenced by variations in ambient conditions in the laboratory (particularly temperature and relative humidity). Application of the Dieng method in different laboratories with varying ambient conditions will lead to improved reproducibility and comparability of results. In addition, results from the Dieng apparatus can be collected using a connected computer and this represents an important advance also.