Wine Chemistry and Biochemistry

142 R. Marchal and P. Jeandet

0

100

200

300

400

500

600

700

800

900

Control

must

Flotated

must (no

fining)

B 20 FG 10 Gluten 20Si 10 B 20 +

FG 10

B 20 +

Gluten

20

B 20 + FG 10

+ Si 10

B 20 +

Gluten 20

+ Si 10

T

urbi

dit

y (NTU)

31%

11.5%

4.9% 36.3%

15.5%

24.9%

7 8.9%

25%

7 9.6%

5.3%

16. 7 %

8.5%

27 % 4.1%13%

6.5%

20. 7 %

–32%

–23NTU

–22%

–10NTU

Fig. 5.4Clarification of a Muscat must using the flotation technique (laboratory experiments).
Influence of different fining agents (each value is the average of two experiments).Upper val-
ues(%): residual NTU compared to the control must;lower values(% in italics): residual NTU
compared to the flotated must

5.1.4.3 Industrial Flotation Experiments

Trials were conducted on an industrial scale (Fig. 5.5). After fining, the must was

pressurized with air in the saturation column (6 bar) and sent (140 hL/h) into the

flotation tank (80 hL). An aspiration system collected the flotation foam (60 hL)

on the top of the flotation tank. Particles of the foam were removed with a rotary

filter and a clear must (35 hL) was obtained. In the following example, two identical

tanks, containing exactly the same must, were treated with B 20 +Si 10 +gluten 20

or with B 20 +Si 10 +FG 20. (FG, fish glue soluble gelatin; B, bentonite; Si, silica gel;

Si P B

Compressed air

(1 hr before flotation)

500hl

Trouble

must

+ pectinases

s

Compressed air

Column for

pressurization

(6 bars)

Flotation tank

Foams Foams

Flowing of

clear must

Clarified must

460hL

Motor

60hL

Flotation

foam

Rotary

filter

Clear must from foam (35hL)

Aspiration

Fining agents

Silica gel (Si)

Proteins (P)

Bentonite (B)

Fig. 5.5Description of the industrial flotator