AMONGST TANKS & BARRELS
In order to optimise the production of quality Pinotage, the following basic guidelines for the vinification of Pinotage are recommended for South African conditions. These guidelines are based on extensive research and practical experience.
Harvest timing and conditions
Upon sufficient physiological ripeness and an optimal sugar concentration of 24º to 26º Balling (minimum 23,0º Balling), the grapes should be harvested at temperatures lower than 30ºC. Acid and pH levels of TA > 5.5 g/l and pH < 3.70 respectively are recommended.
Crushing, destemming and sulphuring
If possible, sorting of grapes should be done to ensure the highest possible quality. Roller width should be adjusted to maintain a percentage of whole berries for early marketing wines and for fuller style wines less whole berries should be let through. Depending on grape quality, sulphur dioxide should be evenly added at levels of 30 to 60 mg/kg.
Juice analyses and acid adjustments
A representative sample for sugar, acid and pH analyses should be collected. The analysis of malic- and tartartic acid as well as FAN levels is recommended. Adjust the TA and pH by the addition of tartaric acid according to the general recommendation of TA >7.0 g/l and pH<3.60. Note that the adjustment of TA and pH according to the levels of malic- and tartaric acid will be more accurate. It is also recommended that when adding tartaric acid, a single addition should not exceed 3 g/l for juice and 0.5 g/l for wine.
Cold soaking at temperatures <20ºC and with daily pump-overs is recommended for improved colour extraction, but only on healthy grapes. Immediately inoculate with yeast if spontaneous fermentation is observed.
Alcoholic fermentation and post-fermentative skin contact
Yeast choice should be primarily based on alcohol and cold tolerance and secondarily on aroma production. Aeration during yeast rehydration is recommended for high risk fermentations (e.g. high sugar concentrations, potential nutrient imbalances and low temperatures). An enhanced estery character, suitable for wines that will be marketed earlier, will develop at fermentation temperatures of 22 – 24ºC. A less estery character, for full-bodied wines that will be marketed later, following wood maturation, is possible at temperatures of 24 – 28ºC. Fermentation at 28 – 32ºC is only recommended for full-bodied wines. Frequent mixing of skins and must by pump-overs or punch-downs is important. Skin cap temperatures exceeding 32ºC could potentially cause stuck or sluggish fermentations, or even bacterial spoilage.
Frequent pump-overs or punch-downs during the early stages of fermentation will give less tannins as well as softer tannins. Concentrated aeration during the last phase of fermentation produces a softer tannin structure. Skin contact towards the end of fermentation or after fermentation depends on the required wine style, but pressing is usually done before completion of fermentation (2 to 8º Balling). Extended maceration is only recommended for wines made from healthy grapes harvested at optimum ripeness and that are destined for further maturation. Sensory evaluation on a daily basis is necessary.
Pressing and handling of press wine
Pressing actions (duration and pressure) are regulated by the sugar and phenolic levels as determined by sensory evaluation. Keep press wine separate if pressed at 0 to 2º Balling and check the sugar concentration of both the free-run and press wine. Keep the press wine separate if the difference is more than 1º Balling and let both fractions ferment until dry.
Racking is recommended after complete alcoholic fermentation, after malolactic fermentation (MLF) and after 3 months barrel maturation.
Adjust pH to values of less than 3.6 by addition of tartaric acid, especially in wines that will undergo MLF. The analyses of malic- and tartaric acid concentrations may be useful. Apply the set formulas for pH correction.
MLF can be prevented by storing wine at <15ºC, adding sulphur dioxide and performing sterile filtration. Lysozyme can also be used to arrest MLF or delay the onset of MLF. MLF can be encouraged by inoculation of a pure culture and maintaining wine temperatures of >18 ºC. Confirm the completion of MLF by malic acid analyses and rack the wine after completion of MLF.
Acid and pH balancing after MLF
Correct pH by the addition of tartaric acid. Note that the preferred pH level is <3.60 and the preferred acid level is <6.2 g/l.
Filtration, fining and post-MLF sulphuring
Check bacteria levels and filter wines with high levels. Wines destined for barrel maturation should be fined with protein fining agents before ageing if they are harsh and astringent. Add 50 mg/l sulphur dioxide shortly after MLF or for wines with no MLF. Adjust total sulphur dioxide levels to 70 – 80 mg/l after a week and maintain a level of >70 mg/l total sulphur dioxide during storage of the wine.
Wine storage, barrel maturation and pre-bottling
Wines must be stored in full tanks and at constant temperatures of <20ºC. As for barrel maturation, barrel choice and length of maturation will depend on wine style. A percentage of new wood is recommended for full-bodied, wood-matured wines. Barrel topping should take place monthly, at least, and sensory evaluation of wines used for topping is necessary. The recommended time of barrel maturation is >6 months, during which even temperatures (<20ºC) and humidity control are necessary. Total sulphur dioxide levels of >70mg/l should be maintained. Final filtration before bottling should be preceded by tartrate stabilisation and tanning fining, if necessary.