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Bentonite fining is the most popular treatment used to remove proteins in white and rosé wines. The usual heat test used to adjust the bentonite dose consists of heating the wine during 30 min at 80 °C. At this temperature, all of the proteins are unfolded, and this can lead to an overestimation of the dose. We have shown that proteins adsorb on bentonite in a specific order and, more importantly, that the proteins responsible for haze formation adsorb first. Fluorescence spectroscopy showed that this is due to the structural properties of proteins, which can be classified as hard and soft proteins. Alternative heat tests were performed at a lower temperature (40 °C) and showed a better correlation with accelerated aging. These tests were also less dependent upon the wine pH.

The regulation of oenological practices put in place in Europe at the beginning of the 20th century was intended to save traditional viticulture from the excesses of liberalism and the manufacture of artificial wines. The foundations of this regulation have been taken up by European texts and are still in force today. Over the last fifteen years, in order to improve the competitiveness of the sector in a context of global competition, practices have become more and more numerous and they are sometimes moving away from these foundations. The new environmental, societal and commercial challenges facing the wine sector may well call into question the current production model and give rise to reflections on the definition of wine.