II.2.1.14 Flotation

Definition:

An operation consisting of injecting gas into a must in such a way as to cause particles or microorganisms to rise to its surface.

Objectives:

a)        Obtain rapid clarification with or without adding clarifying agents;

II.2.1.13 Desulphiting

Definition :

Operation designed to remove from the must, completely or partially, the sulphur dioxide that had been introduced by sulphiting.

Objectives :

a)        To render the must suitable for the production of different products, notably concentrated must, grape juice and special wines.

II.2.1.12.4 Concentration of must by cold

Definition:

Process consisting in concentrating must by partial freezing and elimination of the ice thus formed.

Objective:

See II.2.1.12 a and c ‘Partial dehydratation of musts’

Prescriptions:

A light sulfiting of the must before freezing is recommended.

II.2.1.12.3 Partial evaporation under atmospheric pressure

Definition:

Process consisting in eliminating a certain quantity of water from grape must in an evaporational system under atmospheric pressure.

Objectives:

See II.2.1.12. b, c, and d ‘Partial dehydratation of musts’

Prescriptions:

II.2.1.12.2 Partial evaporation

Definition:

Prescriptions to concentrate musts at a moderate temperature by evaporation of a portion of the water in the thermal exchanger under a high vacuum.

Objective:

See the sheet on II.2.1.12 “Partial dehydration of musts”.

II.2.1.12.1 Concentration

Definition :

Process consisting of concentrating must by elimination of part of the water through specific membranes under the action of a pressure greater than the osmotic pressure of the must.

Objective :

To obtain an enrichment of the must, especially in sugars.

II.2.1.12 Partial dehydratation of musts

Definition:

Process consisting in the elimination of a certain quantity of water in grape must.

Objectives:

a)        To increase the sugar level of a must intended to be fermented;

II.2.1.11.1 Filtration on a filter bed

Classification:

• Diatomite: processing aid
• Perlite : processing aid

Definition :

Filtration of the must through a bed of auxiliary filter material.

Objective :

II.2.1.11 Filtration

Definition :

Physical process by which must is passed through appropriate filters that retain particles in suspension.

Objective :

Clarification of the must.

Prescriptions :

a)        Filtration is practised with or without additives.

II.2.1.10 Treatment with silicon dioxide

Classification

• Colloidal solution of silicon dioxide: Processing aid

Definition :

Addition to must of a colloidal solution of silicon dioxide coupled with the addition of a gelatin solution.

Objective :