Macrowine 2021
IVES 9 IVES Conference Series 9 In line monitoring of red wine fermentations using ir spectrospcopy

In line monitoring of red wine fermentations using ir spectrospcopy


There has been a shift in modern industry to implement non-destructive and non-invasive process monitoring techniques (Helmdach et al., 2013). This is primarily to ensure that process conditions are maintained at optimal set points, thus improving consistency, efficiency, and control. Implementation of infrared technology and chemometrics in the wine industry has been extensively studied and has been found to be a suitable method of process monitoring, especially when considered in the context of phenolic extraction. However, these studies have conducted spectroscopic analysis off-line and with highly clarified samples (Aleixandre-Tudo et al., 2018; Cavaglia et al., 2020). For the technology to be more applicable to a real life scenario, a shift towards in-line monitoring must be made. The ultimate aim of this study was the development of an automated sampling and analysis system. This system would allow spectroscopic and chemometric technology to become more commonly in commercial cellars and for precision monitoring of phenolic extraction. May challenges exist when sampling directly from a fermentation tank and these can include high levels of turbidity, pipe blockages, exposure to oxygen, and ensuring that a sample is representative of the contents of the fermentation vessel. Turbidity, in particular, is a concern when utilizing spectroscopic methods as the suspended solids may interfere with the trajectory of the radiation, resulting in abnormal spectra and, therefore, inaccurate measurements. A prototype system making use of a series of filter screens was developed and prototyped to determine whether automated sampling and analysis would be possible in a cellar with multiple tanks and a single instrument. Automation software was developed to initiate the IR scanning and the subsequent analysis of the sample, displaying the results for tannin content, anthocyanin and polymeric pigment content, total phenolic index and colour density graphically for the user or winemaker. In addition to this, chemometric models were built to account for the effect of suspended solids in a fermenting sample. The system, as a whole, showed promise with samples being successfully drawn from the tanks and analysed. Lastly, statistical analysis showed that the chemometric models were robust, accurate and suitable for the intended application.


Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article


Kiera Nareece Lambrecht 

Stellenbosch University, South African Grape and Wine Research Institute (SAGWRI), Department of Viticulture and Oenology,Dr José Aleixandre-Tudo, Universitat Politecnica de Valencia, Instituto de Ingenieria de Alimentos para el Desarrollo (IIAD), Departamento de Tecnología de Alimentos and Stellenbosch University, South African Grape and Wine Research Institute (SAGWRI), Department of Viticulture and Oenology  Prof Wessel Du Toit, Stellenbosch University, South African Grape and Wine Research (SAGWRI) Institute, Department of Viticulture and Oenology

Contact the author


in-line monitoring, process control, spectroscopy, chemometrics


Related articles…

Assessing the climate change vulnerability of European winegrowing regions by combining exposure, sensitivity and adaptive capacity indicators

Winegrowing regions recognized as protected designations of origin (PDOs) are closely tied to well defined geographic locations with a specific set of pedoclimatic attributes and strictly regulated by legal specifications. However, climate change is increasingly threatening these regions by changing local conditions and altering winegrowing processes. The vulnerability to these changes is largely heterogenous across different winegrowing regions because it is determined by individual characteristics of each region, including the capacity to adapt to new climatic conditions and the sensitivity to climate change, which depend not only on natural, but also socioeconomic and legal factors. Accurate vulnerability assessments therefore need to combine information about adaptive capacity and climate change sensitivity with projected exposure to new climatic conditions. However, most existing studies focus on specific impacts neglecting important interactions between the different factors that determine climate change vulnerability. Here, we present the first comprehensive vulnerability assessment of European wine PDOs that spatially combines multiple indicators of adaptive capacity and climate change sensitivity with high-resolution climate projections. We found that the climate change vulnerability of PDO areas largely depends on the complex interactions between physical and socioeconomic factors. Homogenous topographic conditions and a narrow varietal spectrum increase climate change vulnerability, while the skills and education of farmers, together with a good economic situation, decrease their vulnerability. Assessments of climate change consequences therefore need to consider multiple variables as well as their interrelations to provide a comprehensive understanding of the expected impacts of climate change on European PDOs. Our results provide the first vulnerability assessment for European winegrowing regions at high spatiotemporal resolution that includes multiple factors related to climate exposure, sensitivity, and adaptive capacity on the level of single winegrowing regions. They will therefore help to identify hot spots of climate change vulnerability among European PDOs and efficiently direct adaptation strategies.

From local classification to regional zoning. The use of a geographic information system (GIS) in Franconia / Germany. Part 3: classification of soil parameters in vineyards

La conservation de la fertilité du sol est un aspect primordial dans la viticulture durable. Différents paramètres, comme par exemple la topographie, la composition du sol, les conditions climatiques, influencent la fertilité du sol des surfaces viticoes.

Wine microbial diversity and cross-over applications: emerging results and future perspectives

AIM: Cross-over applications are an emerging technological approach in food microbiology where a microorganism from one traditional specific fermentation process is used to improve quality and safety in another agri-food production/chain (Dank et al., 2021). A complex microbial diversity is found in association with fermentation in wine, including Saccharomyces, non-Saccharomyces and malolactic bacteria,  all microorganisms versatile in terms of enological utilisation (Tempère et al., 2018). Here, we propose a systematic literature review highlighting the existing trends and possible future applications related to cross-over exploitation of wine-related microbiota. 

Whole bunch fermentation: adding complexity, or just making ‘green’ wine?

Certain grape varieties contain negligible levels of isobutyl methoxypyrazine (IBMP) in grapes. However, it has long been known that grape stems

Cover crop influence on water relations, yield, grape and wine composition of Pinot noir

The effect of cover crop on the water relations, yield and grape composition of Pinot noir vines was investigated during two seasons (2003 and 2004) in a gravely soil located in Tarragona (Spain). Seventeen-year-old vines, grafted onto R110 and trained onto a Ballerina training system, were used.