Macrowine 2021
IVES 9 IVES Conference Series 9 Whole bunch fermentation: adding complexity, or just making ‘green’ wine?

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

Abstract

AIM: Certain grape varieties contain negligible levels of isobutyl methoxypyrazine (IBMP) in grapes. However, it has long been known that grape stems may have a high concentration of IBMP. The study aimed to discover the extent to which whole bunch addition during fermentation contributes to ‘capsicum’ (green) flavour and aroma in wine by imparting IBMP. It was also of interest to determine whether additional tannin could be extracted from stem contact, which was expected to impact wine astringency.  

METHODS: Pinot noir and Shiraz grapes were either fermented either completely crushed, or as 100% whole bunches. Other treatments had proportional whole bunch addition at 25%, 50% or 75%. Wines were put through descriptive sensory analysis after 10 months and multiple volatile and non-volatile compounds were analysed at the same time.  

RESULTS:  For both varieties, the sensory scores for ‘green capsicum’ and the concentration of IBMP were highly correlated with the proportion of whole bunches in the ferment. Volatile compounds other than IBMP were increased by whole bunch fermentations, and were α-terpineol, β-citronellol and E-2-hexenol. For Shiraz, the wood-derived volatiles guaiacol and vanillin increased with whole-bunch inclusion, while for Pinot noir ethyl cinnamate increased, possibly reflecting that some carbonic maceration occurred. In Shiraz wines, the concentration of tannin and the perception of astringency increased with the inclusion of whole bunches, but this was not observed for Pinot noir. Whole-bunch ferments from both grape varieties had lower levels of polysaccharide in the finished wine, primarily due to a lower contribution of pectic material.     

CONCLUSIONS: This study showed that winemakers can substantially alter wine volatile and non-volatile composition through whole bunch fermentation. The results will be discussed in terms of potential wine style outcomes for the respective grape varieties, whether whole bunch inclusion might improve the complexity of a wine, or simply introduce unwanted ‘green capsicum’ attributes.

DOI:

Publication date: September 10, 2021

Issue: Macrowine 2021

Type: Article

Authors

Keren Bindon (1), Martin Day (1), Dimitra Capone (2), Stella Kassara (1), Eleanor Bilogrevic (1), Damian Espinase-Nandorfy (1), Flynn Watson (1), Leigh Francis (1)

(1) The Australian Wine Research Institute, Research, Adelaide, Australia
(2) Arc Training Centre For Innovative Wine Production, The University Of Adelaide, Adelaide, Australia

Contact the author

Citation

Related articles…

Comparison of the aroma profile in total and partial dealcoholisation of white and red wines by reverse osmosis

The increasing demand for low-alcohol and non-alcoholic wines has led to the development of advanced dealcoholisation techniques aimed at preserving wine quality while reducing ethanol content. Reverse osmosis is one of the most widely used membrane-based processes for the selective removal of ethanol [1].

Read More

Landscape marketing and landscape reality: what is the relationship? The case of the Loire Valley vineyards

This issue poses two questions: the relationship between beauty and taste (is landscape quality an index of wine quality ?), and the gap or the conformity between our image of the “terroir” and the visible reality. The landscape is both an object and a representation.

Read More

Genetic traceability of the varietal origin of wines: a robust application for must and wines during alcoholic fermentation

Industry and regulatory agencies have developed regulations to ensure authenticity and compliance with wine composition limits. However, this can be truncated by the absence of simple and robust analytical methodologies, uninfluenced by the environment, different oenological techniques and cultural practices. Genetic fingerprinting is the most powerful tool for unequivocal varietal identification; it is not affected by the environment or agronomic practices; however, its usefulness in musts and wines has been controversial and there is currently no routine certification of varietal origin based on DNA analysis.

Read More

Generation of radicals in wine by cavitation and study of their interaction with metals, phenols and carboxylic acids

High-power ultrasounds have been related to an accelerated aging of wines, an effect that has been associated to the formation of radical species caused by the cavitation phenomenon [1]. This phenomenon consists of the formation of bubbles in the liquid medium that, when they collapse, cause high-pressure hot spots and temperatures of up to 4800 k [2], notably increasing the reactivity in the medium.

Read More

Grape ripening delaying with combined use of leaf removal and natural shading in Manto negro (Vitis vinifera L.) under deficit irrigation

The increasing frequency of heat waves during grape ripening presents challenges for the production of high-quality wine grapes. This underscores the significance of developing effective irrigation and canopy management techniques to optimize both yield and grape quality.
A field experiment was carried out during 2021 and 2022 using Manto negro wine grapes to study the effect of two irrigation strategies and different light exposure levels on grape quality. In a four-block experimental vineyard at Bodega Ribas in Mallorca, two irrigation treatments—moderate and severe deficit irrigation—were implemented. Within each irrigation plot, three light exposure treatments were randomly assigned, encompassing exposed clusters from pea size, non-exposed clusters, and shaded clusters after softening.

Read More