Use of mathematical laws for optimizing the dose of swollen and dry bentonite during the fining of white wines. Part II : influence on the volume of lies and economics

Abstract

A Sauvignon white wine was fined with a dry bentonite (BS), e.g directly incorporated in the wine without swelling treatment, or with the same bentonite swelled in water 24 hours before utilization (BG). The volumes of lees generated by the fining were situated between 0,27 and 1,51 % (v/v) for BS, and between 1,07 and 4,59 % (v/v) for BG. The relation between the quantity of bentonite introduced in the wine (g/hl) and the volume of lees (v/v) follows a power law. The volume of lees only increased by 70 % when the dose of swelled bentonite was doubled; for higher doses of bentonite (rarely used), one can observe a packing of the lees. For BS, lees were approximately twice more volumetric when the dose was doubled. We also observe very good relationship between the clarifying efficiency and the volume of lees. When the clarifying efficiency of BG increased by 10 % the volume of lees increased by 74 %. For BS, when the clarifying efficiency increased by 10 % the volume of lees increased by 86 % because of its low efficiency during clarification. The decrease of the natural proteic haze risk and the volume of lees generated by bentonite fining were also closely correlated by an exponential law. For BG, the mathematical law showed that when the volume of lees increased by 0,1 % (v/v), colloidal haze risk decreased only by 22 %. On the contrary, for BS, when the volume of lees increased by 0,1 %, proteic haze risk decreased by 44 %. Finally, the estimation of the cost of fining showed that the use of a non swelled bentonite was economically more interesting than the utilization of a swelled bentonite. This was true when this Sauvignon wine is sold both in bottle or in bulk. For the studied wine, the estimated winning was 115 euros for 10 hl sold in bulk.