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Schneider - Oenologie
Volker Schneider
Rupertusweg 16
55413 Weiler bei Bingen
Germany

E-Mail: Schneider.Oenologie@gmail.com

Technical

 

Wine screw cap closures: The next generation
In: Australian & New Zealand Grapegrower & Winemaker, 03/2017, 50-52.
Screw cap liners with a very low oxygen transmission rate (OTR) protect wines against oxidative ageing, but they also favour the occurrence of post-bottling reduction flavour. This article describes the concept of a new screw cap liner capable of mitigating the appearance of reductive taints. The innovative liner includes a layer containing immobilized copper binding volatile sulfur compounds present in the bottle headspace. Their scavenging by copper takes place within the liner. None of the copper leaches into the wine. The OTR of this liner is indistinguishable from that of a tin/Saran liner.
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Tannin and oxygen management in red wines
A detailed Powerpoint presentation from lectures and seminars.
with special consideration of cool climate conditions, tannin quality and quantity and how to measure it, sensory impact of micro- and macrooxygenation, tannin polymerization, sensory interactions between acidity and astringency, use and quality of oak, interactions between SO2 and oxygen, SO2 stability at bottling, etc.
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Primer on atypical aging
In: Wines and Vines, No. 4, 2010, 45-51.
Atypical aging is induced by a hormonal stress in the vines prompting the conversion of the plant hormon 3-indolacetic acid into the odor-active 2-aminoacetophenone after SO2 is added to white wines post fermentation. The typical off-flavor reminiscent of mothballs, acacia blossom, or laundry, can develop as a premature aroma defect that has no connection with oxygen uptake or oxidative degradation. However, the addition of ascorbic acid is the only useful enological means to prevent its appearance in wines made from affected fruit. Long-term solutions must be sought in the vineyard to avoid stressed fruit. The sensory identification and discrimation from other forms of aging is crucial in order to avoid inappropriate counter-measures.
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Atypical aging
A concise Powerpoint presentation on the atypical aging defect in white wines, its viticultural origins and enological countermeasures.
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Aromatic and phenolic ripeness
Unpublished communication to the Pennsylvania Quality Association, 2010.
Sugar content of grapes is an unreliable parameter to predict grape and wine quality. Under conditions of progressing global climate change, extreme climates, overcropping, and premature harvest, the correlation between Brix readings and overall quality lacks any practical significance. Alternatively, the concept of physiological maturity, comprising aromatic and phenolic ripeness, is presented, Analytical and sensory means of their assessment  in grape samples are discussed.
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The pH-issue in winemaking
Unpublished communication for the Pennsylvania Quality Association, 2012.
High pH is a major concern in winemaking since it affects SO2 effectiveness and microbiological stability. However, lowering pH by acid additions generates drastic alterations on the palate that frequently distort the desired wine style. Filtration and sterile bottling are efficient means of risk management in high pH winemaking.
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The enological and sensory significance of acetaldehyde
In: Ithaka Journal for Terroir, Wine, and Biodiversity, 2009.
This paper reports on the microbiological production and breakdown of acetaldehyde (ethanal) in wine, its production and decay by chemical pathways, its interaction with sulfur dioxide, and sensory definitions and frequent misunderstandings related to it.
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