II.2.1.24 Fining using yeast protein extracts

Classification :

• Yeast protein extracts: processing aid

Definition:

Addition of yeast protein extracts for fining musts

Objectives:

a)        Facilitate racking of musts

b)       Reduce turbidity of musts by precipitating suspended particles

c)        Reduce quantity of tannin

d)       Improve filtrability of wine derived from fined musts

Prescriptions:

a)        The doses used are determined beforehand by laboratory trials (fining point)

b)       Maximum dose to be used, determined by a test of efficiency in laboratory must not exceed 30 g/hl

c)        The yeast protein extracts can be used alone or associated with other authorised fining products

d)       The deposits from the fining of musts are eliminated from the musts by physical processes

e)       The yeast protein extracts must comply with the prescriptions of the International Oenological Codex.

Recommendation of the OIV:

Admitted

II.2.1.25.1 Reduction of the sugar content in musts through membrane coupling

Definition:

Process that consists in extracting the sugar from musts, by using membrane coupling combining microfiltration or ultrafiltration with nanofiltration or inverted osmosis.

Objectives:

a)        Reducing the sugar content of musts destined for fermentation, with the purpose of obtaining a wine with reduced ethanol content;

Prescriptions:

a)        Refer to the general sheet concerning the reduction of sugar content in musts (sheet II.2.1.25 ‘Reduction of the sugar content in musts Fining using yeast protein extracts’)

b)       The treatment is carried out on a volume of must that is determined according to the required result in terms of sugar content reduction.

c)        The objective of the first step is to prepare the must for the second concentration step and to filter out all the macromolecules smaller than the membrane’s cut-off size.  This step may be done by ultrafiltration.

d)       The ultrafiltrate obtained during the first step of the treatment is then concentrated by nanofiltration or inverted osmosis. The water and the organic acids filtered out by the nanofiltration process can be reintroduced into the treated must

e)       The treatment is to be conducted under the responsibility of an oenologist or of a qualified technician

f)         The membranes used must comply with the prescriptions contained in the “International Oenological Codex”

Recommendation of the OIV:

Admitted

II.2.1.16 Treatment by discontinuous high pressure processes

Definition:

Process that consists in the reduction of indigenous organisms in musts by the use of discontinuous high pressure processes, with pressures higher than 150 MPa (1500 bar).

Objective

a)        To reduce the microbial loads of indigenous microorganisms, especially yeasts,

b)       To reduce SO2 levels used in winemaking,

c)        To accelerate maceration in red winemaking.

Prescriptions

a)        The high hydrostatic pressure (HHP) technique relates to the use of pressure levels of higher than 150 MPa (1500 bar) during a discontinuous process.

b)       The elimination of yeasts in grapes and musts requires pressure levels of 200-400 MPa.

c)        The elimination of bacterial cells needs pressure levels of 500-600 MPa.

d)       The treatment time range is 2-10 minutes.

e)       If necessary, the increase in temperature may be controlled by supplementary refrigeration.

f)         The increase in temperature and the techniques used should not entail any alteration in the appearance, colour, flavour or taste of the wine.

Recommendation of OIV

Admitted

II.2.1.27 Treatment of grapes by pulsed electric fields

Definition:

A process that consists on the application of sufficiently high pulsed electric fields (PEF) to destemmed and crushed grapes that causes the permeabilization of the cell membranes especially of the grape skins.

Objective

a)        Treatment of red grapes destemmed and crushed by PEF in order to

• Facilitate and increase the extraction of valuable substances such as polyphenols, yeast available nitrogen, aroma compounds including precursors, and other substances located inside the grape cells
• Reduce maceration time

b)       Treatment of white grapes destemmed and crushed by PEF in order to

• Facilitate and increase the extraction of valuable substances such as yeast available nitrogen, aroma compounds including precursors, and other substances located inside the grape cells.

Prescriptions

The technique consists on the application of pulsed electric fields in the range of nanoseconds to milliseconds which are sufficiently high to permeabilize the cell membranes. The destemmed and crushed grapes are treated in at least one treatment chamber with at least one pair of electrodes.

Recommendation of OIV

Admitted

II.2.2 Preservation of musts

II.2.2.1 Treatment with sorbic acid

Definition:

Addition of sorbic acid or potassium sorbate to must.

Objective:

To prevent the alcoholic fermentation of the must.

Recommendation of OIV:

Not admitted.

II.2.2.2 Preservation with alcohol before or during fermentation

Definition:

Addition of rectified alcohol of viticultural origin, wine spirit, alcohol of viticultural origin or rectified food alcohol to the must before or during alcoholic fermentation.

Objectives:

a)        To prevent alcoholic fermentation of a must with a view to producing either a mistelle (see Part I, chap. 5 Mistelles), or a must preserved with alcohol

b)       To stop alcoholic fermentation with a view to obtaining a fortified wine (see Part I, chap. 4.3 Fortified wines).

Prescriptions:

a)        Spirits of viticultural origin shall comply with the prescriptions of the International Oenological Codex and shall conform to the production conditions for these products specified in the present Code.

b)       The nature of the alcohols and spirits added depends on the final product to be produced (see the sections corresponding to the different products).

Recommendation of OIV:

Admitted

II.2.2.3 Preservation by addition of carbon dioxide to must or carbonation of must

Definition:

Addition of carbon dioxide under pressure to must, so as to hinder its fermentation.

Objectives :

a)        Preservation of must destined for the manufacture of juice.

b)       Slowing or stopping fermentation without other intervention.

Prescription :

The gas used shall comply with the prescriptions of the International Oenological Codex.

Recommendation of OIV:

Admitted

II.2.2.4 Pasteurisation

Definition :

Heating must to a specified temperature for a given time.

Objectives :

a)        To inhibit the activity of microorganisms present in the must at the moment of treatment.

b)       To inactivate enzymes present in the must.

Prescriptions :

a)        Pasteurisation is performed in bulk by passing the must through a heat exchanger followed by rapid cooling.

b)       The increase in temperature and the techniques used shall cause no alteration in the appearance, colour, odour or taste of the must.

Recommendation of OIV:

Admitted

II.2.2.5 Protection under inert atmosphere

Classification:

• Nitrogen : processing aid
• Argon : processing aid

Definition :

Operation consistent with creating an inert atmosphere using nitrogen, carbon dioxide and/or argon.

Objective:

To keep the must protected from air to avoid oxidation and the growth of aerobic organisms.

Prescriptions :

The nitrogen, carbon dioxide and argon shall comply with the prescriptions of the International Oenological Codex.

Recommendation of OIV:

Admitted

II.2.2.6 Lysozyme treatment

Classification

• Lysozyme: Processing aid

Definition:

Addition of lysozyme to the must.

Objectives:

a)        Control of the growth and activity of the bacteria responsible for malolactic fermentation of the must.

b)       Reduction of the rate of sulphur dioxide.

Prescriptions:

a)        According to experiments, the maximum dose of 500 mg/l appears to be sufficient to control the growth and the activity of the bacteria responsible for malolactic fermentation during alcoholic fermentation.

b)       Lysozyme cannot totally substitute itself to SO₂ which possesses antioxidant properties. A SO₂ + lysozyme association provides more stable wines.

c)        When must and wine are treated with lysozyme, the accumulated dose must not exceed 500mg/l.

d)       The product must conform to the prescriptions of the International oenological codex.

Recommendation of the OIV:

Admitted

II.2.2.7 Treatment with ascorbic acid

Classification:

• Ascorbic acid: additive
• Erythorbic acid: additive

Definition:

Addition of ascorbic acid to must.

Objectives:

a)        Protect the aromatic substances of the grape, through the antioxidant properties of the product, against the influence of oxygen in the air.

b)       Limit the formation of ethanal during alcoholic fermentation, through the combination with sulphur dioxide.

c)        Limit the formation of hydrogen sulphide and volatile thiols of fermentation origin.

Prescriptions:

a)        It is recommended to add ascorbic acid immediately after the grape’s crushing.

b)       The dose used, cumulated if necessary, with that used on the grapes, shall not exceed 250 mg/l.

c)        It is advisable to use ascorbic acid with sulphur dioxide.

d)       The ascorbic acid shall comply with the prescriptions of the International Oenological Codex.

Recommendation of OIV:

Admitted

II.2.2.8 Treatment of must with glutathione

Classification:

• Glutathione: additive

Definition:

Addition of glutathione to musts.

Objective:

To limit the intensity of oxidation phenomena in musts, thanks to the ability of glutathione to trap quinones and reduce their oxidative activity.

Prescriptions:

a)        It is advised to add the glutathione while obtaining the musts or at the start of alcoholic fermentation, ensuring that, prior to and during alcoholic fermentation, the assimilable nitrogen level is sufficient to avoid the metabolism of glutathione by the yeast;

b)       the dose used should not exceed 20 mg/L;

c)        the glutathione must be in a reduced form and comply with the prescriptions of the International Oenological Codex.

OIV recommendation:

Admitted

II.2.2.9 Treatment using inactivated yeasts with guaranteed glutathione levels

Classification:

inactivated yeasts with guaranteed glutathione levels: processing aids

Definition:

Addition of inactivated yeasts whose cells have guaranteed reduced-glutathione levels.

Objectives:

a)        To limit the oxidation of certain varietal aromatic compounds revealed by the metabolism of yeasts (particularly thiols);

b)       to promote yeast metabolism through the provision of naturally-occurring nutritional compounds.

Prescriptions:

a)        The addition of inactivated yeasts with guaranteed glutathione levels at the start or during the alcoholic fermentation is recommended, ensuring that the assimilable nitrogen level is sufficient to avoid the use of glutathione by the fermentative yeasts;

b)       the dose used of glutathione, supplied directly or via yeasts with guaranteed glutathione levels, should not exceed 20 mg/L, in order to avoid any risk of reduction and the emergence of a yeast taste;

c)        the inactivated yeasts with guaranteed glutathione levels should contain a reduced form of glutathione; this may be accompanied by the presence of its precursors (cysteine and particularly gamma-glutamylcysteine);

d)       the inactivated yeasts with guaranteed glutathione levels should comply with the prescriptions of the International Oenological Codex.

Recommendation of the OIV:

Admitted

II.2.2.10 Treatment by continuous high pressure processes

Definition:

Operation for the elimination of wild microorganisms in musts by high pressure processing (above 200 MPa or 2000 bar) in continuous. In UHPH, the pressure is usually ranging 300-400 MPa.

Objectives:

• To reduce or eliminate the load of wild microorganisms, mainly yeasts, preserving the organoleptic quality.
• To reduce the amount of SO2 used in winemaking.
• To reduce or inactivate the activity of oxidative enzymes.
• To get grape must stable from the microbiological point of view.
• To obtain partially fermented musts.

Prescriptions:

a)        The ultra high pressure homogenization technique (UHPH) consists in the application of pressures higher than 200 Mpa (2000 bar) by continuous pumping.

• UHPH: continuous process that could be better integrated in the pretreatment of musts.

b)       To eliminate the yeasts of the musts, pressures of 200-400 Mpa are needed.

c)        To eliminate bacteria, pressures of 200-400 Mpa are needed.

d)       The treatment speed can range from 40 L / h to 40,000 L / h.

e)       If necessary, the increase in temperature can be controlled with additional refrigeration.

f)         Neither the increase in temperature nor the techniques used should produce significant alterations in the appearance, color, smell or taste of the wine.

g)        The procedures must conform to the specifications of the International Oenological Codex.

Recommendation of the OIV:

Admitted

II.2.2.11 Treatment of musts using adsorbent styrene-divinylbenzene beads

Definition:

Physical process of reduction or elimination of organoleptic deviations characterised as “earthy-musty” by the appropriate and controlled percolation of musts at a high flow rate through adsorbent styrene-divinylbenzene beads.

Objectives:

a)        To eliminate the perception of organoleptic deviations characterised as “earthy-musty” by the reduction in concentration or elimination of one of the main molecules responsible, geosmine.

Prescriptions:

a)        Treatment should be carried out on clarified musts with turbidities of less than 30 NTU (nephelometric turbidity units). With regard to red grapes, a preliminary treatment separating the liquid phase from the solid parts should be envisaged.

b)       The quantity of adsorbent beads to be used in the column and the must flow rate are to be determined based on the initial geosmine content.

c)        The adsorbent beads are placed in a column that is compliant with standards for food contact materials.

d)       The adsorbent beads implanted and the condition of their use should comply with the prescriptions of the International Oenological Codex.

Recommendation of the OIV:

Admitted

II.2.2.12 Use of Aspergillopepsin I to remove haze-forming proteins

Definition:

The addition to grape must of Aspergillopepsin I from Aspergillus spp. to remove haze-forming proteins.

Objectives:

To prevent protein haze in still white, rosé wines and sparkling wines.

Prescriptions:

a)        Addition of Aspergillopepsin I preparation to must prior to initiation of fermentation

b)       After addition of Aspergillopepsin I preparation, one short-term must heating must be applied as it contributes to the unfolding of haze-forming proteins and facilitates their enzymatic degradation by proteases, as well as leads to a denaturation of the protease itself.

This single heat treatment must take into account:

• the activity of Aspergillopepsin I preparation as regards the temperature
• the quantity of Aspergillopepsin I used
• the minimum temperature of treatment should be at or above the denaturation temperature of the proteins, generally comprised between 60 and 75 °C.
• the heating time, generally around 1 minute. Too long heating time could induce negative organoleptic impact.

This loss of three-dimensional conformation of TLPs (Thaumatin Like Proteins) is reversible, so the heating has to be simultaneous to the addition of enzymes for optimal efficiency.

c)        The must is cooled to an appropriate temperature prior to yeast inoculation.

d)       A filtration must be performed to remove the residual proteins (including added proteases and other proteins).

e)       The enzymes used must comply with the prescriptions of the International Oenological Codex.

Recommendation of the OIV:

Admitted