Technical Yearbook 2023

Fifty years ago, limited literature about winemaking was available. Information only covered basic winemaking topics like sulphur dioxide additions, acid adjustment with tartaric acid, pump-over protocols for red wines and filtration before bottling. Since then, a flood of information has followed. Viticultural subjects like clone differences, rootstocks, pruning and trellising practices, drip irrigation, pesticides and herbicides have been addressed. Winemakers learnt more about different commercial yeast strains, which influence aroma profile, and using new barrels and micro-oxygenation to add more complexity to the wine. The use of phenol analyses also facilitated the management of colour and tannin management. Wine industries are multi-billion investments and cellars must ensure that they are protected and risks are limited. To aid in this, techniques such as controlled alcoholic fermentation, orderly sulphur dioxide management, wine fining, stabilisation and filtration are used. Winemaking has become an increasingly technical manufacturing process that winemakers must control and manage. This led to a counteraction among certain winemakers, who believe that the input of nature should be more important. Decreased intervention during winemaking Decreased intervention during winemaking was initiated in the 1980s in Beaujolais, France. Over the years, some winemakers came to support this concept where winemaking applied by ancestors is promoted. It embraces winemaking without pesticides in the vineyard and chemicals in the cellar. The trend spread globally and is suited to the trend of living healthier, eating natural food and having a positive impact on the planet. This led to a

new wine category known as natural wine. Although it accounts for less than one per cent of the global wine consumption, it is the fastest growing category, especially among the millennial generation. It has no legal definition, but according to the supporting winemakers, it implies that nothing should be added or removed. It is consequently also known as 0/0 winemaking. None or less than 20 mg/L sulphur dioxide and no acids or yeast nutrients should be added; spontaneous instead of pure culture inoculation is applied, and the wines are also not fined or filtered. Seeing that minimum chemical additions are preferred, organic or biodynamically grown grapes are usually used. As a result of the applied practices, or the absence thereof, a quality risk is connected to these natural wines. Apart from their uniqueness, such wines can sometimes be turbid, with vinegary, Brett and mousy aromas instead of positive fruity aromas. However, the opposite can also be true, seeing that not all such wines are bad as their opposition maintains. Although prescribed practices do not exist for such wines, specific guidelines must be followed. Viticultural guidelines for natural wines ● Sound grapes of any grape cultivar on any soil type can be used, but scarce cultivars (like Palomino and Cinsaut in South Africa) are sometimes preferred. ● No or limited soil preparation is applied, although cover crops are frequently planted. Only elementary sulphur powder, if required, instead of chemical products is used for disease or pest control.

Winemaking guidelines for natural wines ● Grape sorting can vary from no to hand sorting to ensure that sound grapes are used. physiological ripeness by applying analytical or berry evaluation. Emphasis is especially placed on lower pH and relatively high fixed acid concentration, seeing that acid adjustment is not made. ● Grapes can be destemmed and crushed, or whole bunch pressing can be applied. ● No sulphur dioxide (SO 2 ) is usually added, but if so the total SO 2 concentration is limited to 20 mg/L. ● Alcoholic and malolactic fermentation (MLF) can occur in old used barrels or stainless-steel tanks. No yeast or bacteria cultures are inoculated, and both fermentations are spontaneous. No temperature control is applied, or fermentation nutrients added. ● During red winemaking, punch downs or pump overs mix the skins and juice. After completion of the two fermentations, natural clarification takes place, and no fining agents or stabilisation processes are used. Filtration is exceptional and sometimes only done before bottling. ● Limited maturation is used, and after a few months of bottle ageing, the wines are sold in bottles, closed with natural corks.  ● Grapes are picked at

● Although old vines with a low yield, with or without irrigation, are mostly used, they are not required. Reference https://www.wineland.co.za/the-trend-of-natural-winemaking/

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TECHNICAL YEARBOOK 2023