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Quantification of phenolic compounds during red wine fermentation using infrared spectroscopy
Measuring the levels of phenolic compounds during red wine fermentations is a challenging practice. Introduction Phenolic compounds are key components of red wines. Anthocyanins are the group of compounds that give red wine its colour. The levels and composition of...
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Sparkling wine (Part 4): The truth about chilled MCC grapes
In this study, we investigated the effect of grape temperature at pressing on Méthode Cap Classique (MCC) phenolic extraction, content and evolution throughout winemaking. Introduction Traditional sparkling wine (TSW) winemakers do not desire a high phenolic content...
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The art of wine blends
The perception of the ordinary wine consumer and winemakers differs considerably with regard to blends. While the consumer often sees it as wines that are made from different varietal wines and a specific cultivar designation cannot be attributed to it, practical wine...
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Soil type effects on Merlot wine quality in Elgin
In wine production, it is important to know the best climate and soil type combination for each cultivar in order to get the best out of each terroir. Introduction While the role of climate as one of the important terroir attributes on wine style and quality is...
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Soil type effects on Sauvignon blanc wine quality in Elgin
The effects of climate as one of the terroir attributes on wine style and quality are generally well understood, while there is much uncertainty concerning those of soil type. Introduction Researchers have reported that soil affects grape composition and...
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Lactobacilli – a source of enzymes for wine aroma
The results indicated that the isolates from the Lactobacilllus species have the same portfolio of enzymes to alter wine aroma as the O. oeni isolates. Oenococcus oeni and Lactobacillus species are the main lactic acid bacteria associated with grape must and wine....
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Yeast nutrition – can we predict the impact on aroma formation?
This study highlights the tremendous potential yeast nutrition has on modulating wine aroma production, particularly in response to branched chain and aromatic amino acid supplementation. By Samantha Fairbairn & Florian Bauer Introduction Yeast assimilable nitrogen...
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Sparkling wine (Part 3): Phenolic composition of traditional style sparkling wine
This review will focus on traditional sparkling wine (TSW) phenolics and how the production process influences them. Introduction TSW vinification is comparable to that of white wine due to the light pressing of the grapes, minimal skin contact and no maceration....
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Meaningful barrel trials
Different factors play a very important role in the character that barrels impart to wine. Irrespective of the wine as such, the wood type, species, grain, origin of the wood and different wood treatments like the drying and toasting method or level play decisive...
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Guidelines to reduce pinking potential in white wines
Pinking is a phenomenon that occurs as soon as white wines with pinking potential are exposed to oxygen. It is common in Sauvignon blanc, but may also occur in Chardonnay, Colombar, Chenin blanc and Viognier (Tobe, 1983). Several scientific publications examine...
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Root-knot nematodes on cover crops
Root-knot nematodes (Meloidogyne spp.) are common in South African vineyards and nursery soils, with M. javanica being the most common species. Soil fumigation and chemical control do not necessarily completely eradicate root-knot nematodes from the soil. Nurserymen...
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The impact of yeast strains on the concentration of oenologically relevant proteins
This study looks at the amount and type of oenologically active proteins, which ultimately impacts on yeast strain selection prior to vinification. Introduction The cell wall can be considered the “exoskeleton” of a yeast cell. It is the cell wall that provides...
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Sparkling wine (Part 2): Do chilled grapes make better MCC?
South African winemakers use many techniques to achieve their award-winning Méthode Cap Classique (MCC) wines. The science behind the sparkle has, however, been little explored. Introduction MCCs have an interesting and unique matrix due to the ageing on lees and...
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The malolactic enzyme – parameters effecting expression
The results obtained showed that pH, ethanol and malic acid play an important role in the expression of the malolactic enzyme gene. Malolactic fermentation is a very important process in winemaking, resulting in deacidification, microbial stability and aroma...
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Positive influence on quality of work in cellars
It is increasingly clear that there is a serious need for the transfer of practical, general knowledge to cellar workers. The Winetech study groups aim to transfer knowledge in a holistic manner and to increase productivity amongst cellar workers. Closer contact with...
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Ring nematode problem not easily solved
The ring nematode, Criconemoides xenoplax, is one of the most common and abundant nematode species in vineyards throughout the Western Cape. Feeding by ring nematodes result in the destruction of grapevine root tissue and a stunted root system with relatively few live...
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The influence of vineyard mechanisation on wine
Increasing labour costs and labour problems have been major causes of vineyard mechanisation. It can however create other advantages and disadvantages and cellars must be prepared to receive such grapes and utilise it optimally. Manual labour will most probably be...
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Non-culture based technologies reveal novel microbes in wine
Many studies on the microbiology of winemaking rely largely on culture-based plating, which is biased towards the microbes that are able to grow on laboratory growth media. More recent methods are culture independent – based on the ability to detect the presence of an...
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