Turbidity, wine fining effect

Fig. 5.1 Effect of different fining procedures on the turbidity of a Chardonnay wine. Measurements were made 28 h after treatments...

In general, the effect of bentonite on red wines is comparable to that of protein fining. After flocculation and sedimentation, wines treated with doses of 25-40 g/hl of bentonite remain stable at low temperatures, staying brilliant and free of turbidity, even after several months. This treatment may be even more effective than gelatin (12 g/hl) or blood albumin (18 g/hl). It should, however, be taken into account that bentonite fixes anthocyanins, not only in discolored white wines but also in roses and young red wines. 

As bentonite flocculates in wine, with a behavior analogous to that of protein fining agents, experiments have been made in using it to clarify wine. In fact, its effectiveness in clarification depends on the type of bentonite and the composition of the wine. The only wines that may be properly clarified are reds or whites with low concentrations of polysaccharides and other protective colloids (Section 9.4.1), as these inhibit the flocculation and settling of the bentonite particles. In some winegrowing areas, bentonite is well suited to clarifying dry white wines, but elsewhere white wines may be more turbid after bentonite treatment than before. 

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