terclim by ICS banner
IVES 9 IVES Conference Series 9 EFFECTS OF INDUCED SUNBURN DAMAGES ON WHITE WINE PROPERTIES

EFFECTS OF INDUCED SUNBURN DAMAGES ON WHITE WINE PROPERTIES

Abstract

Climate change is a great challenge for the environment and affects the wine industry as well. Sunburn damage of sensitive grapes increase with severe heat periods. Besides significant loss of yield sunburn, modifies sensory properties of the wines and may cause climate-related off-flavours. To initiate sun-burn in a controlled way, in 2021 sunburn was directly induced in the vineyard with the GrapeBurner device, exposing grapes of the varieties Riesling and Pinot Blanc with UV and IR radiation. This device was first assembled by Kai Müller of the university in Geisenheim and consists of a carriage with 6 UV/IR lamps. A 15 min irradiation was applied in early September at 60°Oe. Due to the colder season in 2021 the grapes were not harmed by previous sunburn damage. Nevertheless, we used non-defoliated grapes facing north of the vines to ensure that putative damage was only due to applied irradiation and not previous sun exposure. Three weeks after the treatment, a control and the irradiated grapes were harvested and directed to small scale winemaking following a standardised protocol. Sensory evaluation using descriptive analysis with a trained panel was complemented by aroma analysis using an established head space solid phase micro extraction GC-MS method.

For Riesling, the control had a sweeter and fruitier taste, and was reminiscent of ripe fruit, which correlated with a high content of ethyl esters. In contrast, wines from irradiated Riesling grapes had a smokier flavour and correlated with plant derived odorants such as vitispirane, linalool, β-damascenone, and 4-vinylguaiacol. Also the sensory panel described the wines from treated grapes as more astringent and bitter, as well as with a more intense yellow colour. These results were backed by Pinot Blanc trials, as the control was perceived more fruity due to enhanced ethyl esters. Vice versa, wines from the irradiated grapes were more smoky and astringent. In addition, 2-aminoacetophenone was enhanced, causing the atypical aging off-flavour.

These promising results stimulated further trials, in which the length of exposure was varied gradually, to determine a threshold from which irradiation is causing negative sensory and compositional changes. In parallel, mitigation strategies such as applying reflecting particles or adaptation to sun exposure by early defoliation will be examined in lieu of varying UV/IR radiation.

1. Droulia, F., Charalampopoulos, I. (2021). Future Climate Change Impacts on European Viticulture: A Review on Recent Scientific Advances. Atmosphere, 12(4), 495. https://doi.org/10.3390/atmos12040495
2. Gambetta, J. M., Holzapfel, B. P., Stoll, M., Friedel, M. (2021). Sunburn in Grapes: A Review. frontiers in Plant Science, 11, https://doi.org/10.3389/fpls.2020.604691
3. IPCC. (2014). Climate Change: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]Geneva, Switzerland. ISBN: 978-92-9169-143-2

DOI:

Publication date: February 9, 2024

Issue: OENO Macrowine 2023

Type: Poster

Authors

Caterina Szmania1, Ulrich Fischer1,2

1. DLR Rheinpfalz, Neustadt an der Weinstraße/Germany
2. RPTU Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, Kaiserslautern/Germany

Contact the author*

Keywords

climate change, sunburn, white wine, off-flavour

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

Related articles…

DO MICROPLASTICS IN VINEYARD SOIL AFFECT THE BIOAVAILABILITY OF VINE NUTRITION?

Microplastics can alter physicochemical and biogeochemical processes in the soil, but whether these changes have further effects on soil fertility, and if so, whether these effects vary depending on the type of soil in the vineyard and the type of plastic used in the vineyard. Knowing what types of plastics are currently used in vineyards in Slovenian viticultural regions as strings to tie vines to the stake, the aim of our study was to assess the effects of microplastic particles from polypropylene (PP) and polyvinyl chloride (PVC) on the availability of macro (potassium (K), Potassium (K), calcium (Ca), magnesium (Mg) and phosphate (P)) and micronutrients (iron (Fe), copper (Cu), manganese (Mn) and zinc (Zn)) in two vineyard soils contrasting in pH and mineralogy. For this purpose, a short-term soil incubation experiment (120 days) was carried out in which the soil samples were enriched with micro-PP and micro-PVC particles. After the incubation period, macro- and micronutrient availability were measured.

Read More

EVALUATION OF INDIGENOUS CANADIAN YEAST STRAINS AS WINE STARTER CULTURES ON PILOT SCALE FERMENTATIONS

The interactions between geographical and biotic factors, along with the winemaking process, influence the composition and sensorial characteristics of wine¹. In addition to the primary end products of alcoholic fermentation, many secondary metabolites contribute to wine flavor and aroma and their production depends predominantly on the yeast strain carrying out the fermentation. Commercially available strains of S. cerevisiae help improve the reproducibility and predictability of wine quality. However, most commercial wine strains available on the market have been isolated from Europe, are genetically similar, and may not be the ideal strain to reflect the terroir of Canadian vineyards².

Read More

ESTIMATING THE INITIAL OXYGEN RELEASE (IOR) OF CORK CLOSURES

Many factors influence aging of bottled wine, oxygen transfer through the closure is included. The maximum uptake of wine before oxidation begins varies from 60 mg.L-¹ to 180 mg.L-1 for white and red wines respectively [1].
The process of bottling may lead to considerable amounts of oxygen. The actual contribution of the transfer through the closure system becomes relevant at the bottle storage, but the amounts are small compared to prepacking operations [2] and to the total oxygen attained during filling.

Read More

FERMENTATION POTENTIAL OF INDIGENOUS NON-SACCHAROMYCES YEASTS ISOLATED FROM MARAŠTINA GRAPES OF CROATIAN VINEYARDS

The interest in indigenous non-Saccharomyces yeast for use in wine production has increased in recent years because they contribute to the complex character of the wine. The aim of this work was to investigate the fermentation products of ten indigenous strains selected from a collection of native yeasts established at the Institute for Adriatic Crops and Karst Reclamation in 2021, previously isolated from Croatian Maraština grapes, belonging to Hypopichia pseudoburtonii, Metschnikowia pulcherrima, Metschnikowia sinensis, Metschnikowia chrysoperlae, Lachancea thermotolerans, Pichia kluyveri, Hanseniaspora uvarum, Hanseniaspora guillermondii, Hanseniaspora pseudoguillermondii, and Starmerella apicola species, and compare it with commercial non-Saccharomyces and Saccharomyces strains.

Read More

MODULATION OF YEAST-DERIVED AROMA COMPOUNDS IN CHARDONNAY WINES USING ENCAPSULATED DIAMMONIUM PHOSPHATE TO CONTROL NUTRIENT RELEASE

Yeast-derived aroma compounds are the result of different and complex biochemical pathways that mainly occur during alcoholic fermentation. Many of them are related -but not limited- to the availability of nutrients in the fermentation medium and linked to nitrogen metabolism and biomass produced. Besides, the metabolic phase of yeast also regulates the expression of many enzymes involved in the formation of aroma active compounds. The work investigates the overall effect of continuous supplementation of nutrients during alcoholic fermentation of a grape must on the volatile composition of wines.

Read More