Wine Chemistry and Biochemistry

5 Use of Enological Additives for Colloid and Tartrate Salt Stabilization 141

Air for pressurization

Sample of

clear must

Manometer

Gate ¼ 0–10 bars

Tap reducing

the flow

Synthetic

rubber joint

Gas intake

Liquid

exit

Turbidity (NTU)

Foam

Limpid must

Fig. 5.3Description of the laboratory flotation system

one can consider that the use of silica gel significantly improved the efficiency of

the flotation technique when the protein used was the wheat gluten. The difference

was less clear when the protein used was fish glue and it is not possible to write that

B 20 +FG 10 +Si 10 (NTU=35) was more efficient than FG 10 (NTU=42), probably

because bentonite+fish glue gave together a turbidity already very low (Marchal

et al. 2003).

Lastly, the combination Gluten 20 +B 20 +Si 10 was less efficient than the treat-

ment FG 10 +B 20 +Si 10 (−87% and−95.9% in turbidity, compared to that of the

flotated must and the non-treated must, respectively). Here again, results were

confirmed with other experiments during the two previous harvests (Clairette and

Muscat musts).