Viniculture

 

Viniculture

In order to optimise the production of Pinotage wine of quality, the following basic guidelines for the vinification of Pinotage, from harvest to bottling, are recommended for South African conditions.

These guidelines are based on extensive research and practical experience.

The compilation thereof has been undertaken by the Pinotage Association as a service to its members with a view to promote the application of preventive practices rather than to have to revert to dubious corrective actions afterwards.

  • Assess the quality and condition of the grapes in the vineyard by visual inspection and taste.
  • Select and classify blocks for specific wine styles.
  • Monitor ripening process (balling, TA and pH).
Sugar levels
  • Harvest at physiological ripeness by assessment of the colour of the skins and seeds.
  • Minimum: 23,0º Balling.
  • Optimum: 24º to 26º Balling (fuller-style wines).
  • Grapes with sugars higher than 26º Balling must be treated differently, e.g. yeast choice, yeast preparation and fermentation conditions as specified later.
Acid and pH
  • TA: >5.5 g/l.
  • pH: <3.70.
  • Harvest at temperatures below 30ºC.
  • Minimise the time from harvest to cellar.
  • Prevent unnecessary physical damage of berries.
  • Wines for early marketing: adjust roller width to maintain a percentage of whole berries.
  • Fuller-style wines: fewer whole berries.
  • Add sulphur dioxide at levels of 30 to 60 mg/kg, depending on the condition of the grapes.
  • Ensure even distribution of the sulphur dioxide.
  • Collect a representative sample for sugar, acid and pH analyses.
  • Analysis of malic and tartaric acids is recommended.
  • Analysis of FAN levels is recommended.
  • The yield of juice per ton grapes varies according to the specific vineyard from which the grapes were received and their ripening stage. Yield values of 650 litres to 720 litres are normally applicable.
  • Adjust the TA and pH by the addition of tartaric acid according to the following parameters (general recommendations): TA >7.0 g/l. pH<3.60.
  • Adjustment of TA and pH according to the levels of malic and tartaric acids will be more accurate.
  • It is recommended that when adding tartaric acid, a single addition should not exceed 3 g/l for juice and 0.5 g/l for wine.
  • Recommended for improved colour extraction.
  • Only on healthy grapes.
  • Preferably at temperatures <20ºC.
  • Pump-over or punch down on a daily basis.
  • Monitor and inoculate with yeast if spontaneous fermentation has commenced.
  • The only prerequisite is to use yeast adapted to specific conditions, e.g. alcohol tolerance and temperature.
  • Use the correct prescribed rehydration procedures.
  • Aeration of the rehydrated yeast culture is recommended for grapes with higher sugars.
  • Enrichment of juice recommended for grapes received from certain vineyard sites.
    • 22ºC - 24ºC: More estery character; suitable for wines that will be marketed earlier.
    • 24ºC - 28ºC: Less estery character; full-bodied wines; suitable for wines that will be marketed later, after wood maturation.
    • 28ºC - 32ºC: Only recommended for full-bodied wines. Frequent mixing of skins and must is necessary. Danger of stuck fermentation if skin cap temperatures exceed 32ºC.
    • Fermentation at higher temperatures needs better control, e.g. more pump-overs especially during the earlier stages of fermentation.
    • Avoid temperatures >32ºC in the skin cap.
    • Any method whereby good contact between the skins and the fermenting must can be achieved is suitable.
    • More pump-overs or punching down treatments during the early stages of fermentation will give less tannin as well as softer tannin.
    • Concentrated aeration during the last phase of fermentation produces a softer tannin structure.
    • The length of skin contact is dependent on the required wine style.
    • Preferably press before complete fermentation (8º Balling to 2º Balling).
    • Only on wines made from healthy grapes harvested at optimum ripeness.
    • Only recommended for wines that are destined for further maturation.
    • Sensory evaluation on a daily basis is necessary.
    • Pressing actions (time and pressures) are regulated by the sugar and phenolic levels as determined by sensory evaluation
    • Keep press wine separate if pressed at 0º to 2º Balling
    • Check sugar of both free-run and press wine. Keep press wine separate if the difference is more than 1º Balling Let both fractions ferment until dry.
    • A racking after complete fermentation is recommended to remove the gross lees.
    • Racking after MLF is recommended.
    • Racking after 3 months barrel maturation is recommended.
    • Adjust pH to values of less than 3.6 by addition of tartaric acid, especially in wines that will undergo MLF.
    • Analyses of malic and tartaric acid concentrations may be useful. Apply the set formulas for pH correction.
      Preventing malo-lactic fermentation
    • Store wine at temperatures <15ºC.
    • Addition of Sulphur Dioxide is necessary.
    • A sterile filtration is needed.
    Encouraging malo-lactic fermentation
  • Inoculation with a pure culture is recommended.
  • Wine temperatures of >18ºC will limit the time of MLF.
  • Monitor progress of MLF.
  • Confirm completion of MLF by malic acid analyses.
  • Rack wines after completion of MLF.
    • Correct pH by addition of tartaric acid.
    • Preferred pH level is <3.60.
    • Preferred acid level is <6.2 g/l.
    • Check bacteria levels in wines.
    • Filter wines with high bacteria levels.
    • Recommended time for fining is before barrel maturation.
    • Protein fining agents are recommended on harsh, astringent wines to reduce the tannin levels in such wines.
    • Add 50 mg/l shortly after MLF or for wines with no malo-lactic fermentation.
    • Adjust total Sulphur Dioxide levels to 70 - 80 mg/l after one week.
    • Maintain a level of >70 mg/l total Sulphur Dioxide during storage of the wine.
    • Wines must be stored in full tanks.
    • Even temperatures of <20ºC are necessary.
    • Barrel choice and length of maturation depending on wine style.
    • A percentage (depending on wine style) of new wood is recommended for full-bodied, wood-matured wines.
    • Topping of barrels on at least a monthly basis.
    • Sensory evaluation of wines used for topping is necessary.
    • Recommended time of barrel maturation is >6 months.
    • Even temperatures (<20ºC) and humidity control are necessary.
    • Maintain total sulphur dioxide levels of >70mg/l.
    • Tartrate stabilisation if necessary.
    • Fining for tannin if necessary.
    • Final filtration.
    Before harvest:
    • Selection of vineyard blocks for specific wine styles.
    • Vineyard and yield details.
    Before fermentation:
    • Balling, TA, pH.
    • Malic and tartaric acids.
    • Free amino nitrogen concentrations.
    During fermentation:
    • Balling.
    • Temperature.
    • Sensory evaluation on daily basis.
    After fermentation and MLF:
    • TA.
    • PH.
    • Reducing sugar.
    • Volatile acidity.
    • Sulphur dioxide, free and total.
    • Malo-lactic status.
    • Microbiological status.
    • Sensory evaluation on a weekly basis.
    During maturation:
    • Total sulphur dioxide .
    • Volatile acidity.
    • TA and pH (3-month intervals).
    • Sensory evaluation on at least a monthly basis.
    Before bottling:
    • Alcohol.
    • Extract.
    • Reducing sugar.
    • TA.
    • PH.
    • VA.
    • Sulphur Dioxide, free and total.
    • Tartrate stability.
    • Protein stability.
    • Malo-lactic status.
    • Microbiological status.
    • Sensory evaluation.
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