terclim by ICS banner
IVES 9 IVES Conference Series 9 GiESCO 9 GiESCO 2023 9 Understanding the impact of climate change on anthocyanin concentrations in Napa Valley Cabernet Sauvignon

Understanding the impact of climate change on anthocyanin concentrations in Napa Valley Cabernet Sauvignon

Abstract

Context and purpose of the study

Climate change is having a significant impact on the wine industry through more regular drought conditions, fires, and heat events, leading to crop loss. Furthermore, these events can reduce overall quality of the fruit, even when crop yields are not impacted. Anthocyanins are considered one of the most important classes of compounds for red wine production and are known to be sensitive to vine water status and heat events.  Therefore, they are likely to be impacted by environmental conditions across broad spatial scales. In order to evaluate this, a large-scale project was undertaken in 2015 to look at the differences in berry secondary metabolite chemistry across sub-appellations within the Napa Valley, where there is an exceptional amount of climatic diversity. This study was expanded in the 2021 and 2022 growing seasons, to evaluate impacts of agronomic practices and environmental conditions on crop yields and berry chemistry.  The goal of the project is to evaluate the impact of intra- and inter-annual variation in climate on secondary metabolites in Cabernet Sauvignon across a climatically diverse and economically important wine growing region in California; with the aim of increasing the industry’s awareness of potential climate change impacts on important grape secondary metabolites.

Material and methods

In 2015, 66 Cabernet Sauvignon commercial blocks were monitored across 10 sub-appellations within Napa Valley. In 2021 and 2022, 50 commercial blocks were monitored across 13 sub-appellations. Berries were collected from veraison until commercial harvest, with each site having 120 berries being collected every 14 days, totaling 3 to 5 sampling dates per site depending on harvest timing. Berry skins were separated from pulp and seed to extract the phenolics in skins. Extractions were conducted using 2:1 acetone:water (v/v) for 24 hours. Acetone was removed under reduced pressure and samples were then analyzed for high and low molecular weight polyphenols by RP-HPLC. Weather stations collecting hourly temperature, precipitation, humidity and radiation data were present in all blocks, and irrigation records, phenology data, and agronomic practices were collated for all sites. 

Results

Across all years, trends indicate that warmer sub-appellations had lower overall anthocyanin concentrations when compared to cooler sites, yet there was a substantial amount of variation driven by other factors.  Although work has been done within the context of greenhouses looking into the impact of heat on anthocyanin degradation, this work provides a large-scale analysis of the impacts of climate on anthocyanin production across the season in Cabernet Sauvignon.

DOI:

Publication date: June 20, 2023

Issue: GiESCO 2023

Type: Article

Authors

James CAMPBELL1*, Paige BREEN1, Kayla ELMENDORF1, Thibaut SCHOLASCH2, James KENNEDY3, Elisabeth FORRESTEL1

1Department of Viticulture and Enology, University of California, Davis, USA
2Fruition Sciences SAS, Montpellier, France
3Functional Phenolics LLC, Corvallis, Oregon, USA

Contact the author*

Keywords

polyphenols, flavonoids, anthocyanins, climate change, winkler index

Tags

GiESCO | GIESCO 2023 | IVES Conference Series

Citation

Related articles…

IMPACT OF HARVEST DATE ON THE FINE MOLECULAR COMPOSITION OF MUST AND BORDEAUX RED WINE (VAR. MERLOT, CABERNET SAUVIGNON). FOCUS ON ACIDITY AND SENSORY IMPACT AFTER FIVE YEARS OF AGING

Climate change has brought several impacts that are becoming increasingly intense during the last few years and put at risk the quality of the berries or even the plant’s sustainability. Such extreme climatic events impact the composition of the wine while modulating its quality and the consumer preferences (Tempère et al., 2019). The three most important changes that take place in the must are: 1) decrease acidity, 2) increase of the concentration of sugar, hence increase of alcohol in the wine, and 3) modification
of the sensory balance and the development for example of cooked fruit aromas.

IMPACT OF CLIMATIC ZONES ON THE AROMATIC PROFILE OF CORVINA WINES IN THE VALPOLICELLA REGION

In Italy, in the past two decades, the rate of temperature increases (0.0369 °C per year) was slightly higher compared to the world average (0.0313 °C per year). It has also been indicated that the number and intensity of heat waves have increased considerably in the last decades. (IEA, 2022). Viticultural zones can be classified with climatic indexes. Huglin’s index (HI) considers the temperature in a definite area and has been considered as reliable to evaluate the thermal suitability for winegrape production (Zhang et al., 2023).

A synthesis approach on the impact of elevated CO2 on berry physiology and yield of Vitis vinifera

Besides the increase in global mean temperature the second main challenge of a changing climate is the increase in atmospheric carbon dioxide (CO2) in relation to physiology and yield performance of grapevines. The benefits of increasing CO2 levels under greenhouse environment or open field studies have been well investigated for various annual crops. Research under free carbon dioxide enrichment on field-grown perennial plants such as grapevines is limited to a few studies. Further, chamber and greenhouse experiments have been conducted mostly on potted vines under eCO2 conditions.

Microbial ecosystems in wineries – molecular interactions between species and modelling of population dynamics

Microbial ecosystems are primary drivers of viticultural, oenological and other cellar-related processes
such as wastewater treatment. Metagenomic datasets have broadly mapped the vast microbial species
diversity of many of the relevant ecological niches within the broader wine environment, from vineyard
soils to plants and grapes to fermentation. The data highlight that species identities and diversity
significantly impact agronomic performance of vineyards as well as wine quality, but the complexity
of these systems and of microbial growth dynamics has defeated attempts to offer actionable
tools to guide or predict specific outcomes of ecosystem-based interventions.

Searching for the sweet spot: a focus on wine dealcoholization

It is well known that the vinification of grapes at full maturation can produce rich, full-bodied wines,
with intense and complex flavour profiles. However, the juice obtained from such grapes may have very
high sugar concentration, resulting in wines with an excessive concentration of ethanol. In addition, the decoupling between technological maturity and phenolic/aromatic one due to global warming, exacerbates this problem in some wine-growing regions. In parallel with the increase of the mean alcohol content of wines on the market, also the demand for reduced alcohol beverages has increased in recent years, mainly as a result of health and social concerns about the risks related to the consumption of alcohol.