 IVES 9 IVES Conference Series 9 What do we know about the kerosene/petrol aroma in riesling wines?

What do we know about the kerosene/petrol aroma in riesling wines?

Abstract

AIM: 1,1,6-Trimethyl-1,2-dihydronaphthalene (TDN) is a controversial aroma component found in Riesling wines. It belongs to the family of C13-norisoprenoids and is mainly associated with kerosene/petrol notes. TDN can add complexity to the wine aroma at medium – low concentrations and deteriorate the wine bouquet when its content is high. No TDN aromas are usually perceived in young Riesling wines, but they can appear after several years of aging due to the gradual formation of TDN. Management of TDN in Riesling wines is an actual task, since global warming can promote formation of this compound and compromise the aromatic composition of wine. Therefore, the aim of the current work was, firstly, to study the sensory particularities of TDN in Riesling wine at various concentrations. Secondly, to investigate the ability of bottle closures to absorb (scalp) TDN from Riesling wine under various storage conditions. These studies also include the comparative assessment of our findings with previously published data.

METHODS: sensory analysis, GC-MS (SBSE), HPLC,1H-NMR and other methods related to the synthesis and determination of TDN.

RESULTS: First of all, the method of the synthesis of highly purified TDN (95% and 99.5%) was optimized [1]. The obtained TDN was used for the calibrations in GC-MS analysis and for the sensory and TDN scalping studies. As a result, three sensory thresholds for TDN in Riesling wine were determined: detection threshold (about 4 μg/L), recognition threshold (about 10-12 μg/L) and rejection threshold (about 71-82 μg/L) [2]. It was also demonstrated, that the TDN aroma recognition was easier in the cooled wine. The defined thresholds were discussed in relation to the previously reported sensory thresholds determined by other panels and in other wine matrices. In the experiment of TDN scalping, five bottle closures were studied under storage conditions which varied by ambient temperature (14 °C vs 27 °C) and bottle position (horizontal vs vertical) [3]. A large difference in TDN scalping rate was observed for synthetic and glass stoppers depending on the storage conditions. For example, the TDN absorbance from the wine was more than three times faster by synthetic stoppers at the lower storage temperature compared to the higher one (vertical bottle position). Cork stoppers demonstrated a fast scalping process in all storage scenarios, absorbing up to 40% TDN. In the wine bottled with BVS screw caps, only a minor decrease of TDN was found in all storage variants.

CONCLUSIONS:

TDN is an aroma compound that requires effective control tools in Riesling wines. The described results of the sensory analysis can be used as a reference for the desired content of TDN in finished Riesling wines. At the same time, the outcomes of the TDN scalping study provide a deeper understanding of the impact of bottle closures and storage conditions on the TDN content in wine.

DOI:

Publication date: September 22, 2021

Issue: Macrowine 2021

Type: Article

Authors

Andrii Tarasov, Nicoló Giuliani (1), Alexey Dobrydnev (2), Christoph Schuessler (1), Nikolaus Müller, Yulian Volovenko (2), Doris Rauhut (1), Rainer Jung (1)

(1) Hochschule Geisenheim University (Germany) (2) Faculty of Chemistry, Taras Shevchenko National University of Kyiv (Ukraine)

Contact the author

Keywords

1,1,6-trimethyl-1,2-dihydronaphthalene (tdn); sensory threshold; scalping; bottle closure; wine

Citation

Analysis of climatic changes in different areas of Abruzzo region (Central Italy): implications for grape growing

The dynamic evolution of some bioclimatic indices largely used to define the vocation of areas to grape growing was assessed over 43 years (1965-2007) in four sites of the Abruzzo Region (Central Italy).

Oak wood seasoning: impact on oak wood chemical composition and sensory quality of wine

Oak wood selection and maturation are essential steps in the course of barrel fabrication. Given the existence of many factors involved in the choice of raw material and in natural seasoning of oak wood, it is very difficult to determine the real impact of seasoning and selection factors on oak wood composition. A sampling was done to study the evolution of oak wood chemical composition during four seasoning steps: non matured, 12 months, 18 months and 24 months. For this sampling, three selection factors were taken into account: age, grain type and the Polyphenolic Index measured by Oakscan®. Besides extractables
(~10%), three polymers constitute the main part of oak wood: cellulose, hemicelluloses and lignins.

Terroir influence on growth, grapes and grenache wines in the AOC priorat, northeast Spain

The Mediterranean climate of The Priorat AOC, situated behind the coastal mountain range of Tarragona, tends towards continentality with very little precipitation during the vegetation cycle. The soil is poor, dry and rocky, largely composed of slate schist, known as “llicorella”. Vines primarily grow on steep slopes and terraces.

Estimation of degree brix in grapes by proximal hyperspectral sensing and nanosatellite imagery through the random forest regressor

The assessment of physiological parameters in vineyards can be done by direct measurements or by remote, indirect methods. The latter option frequently yields useful data, and development of methods and techniques that make them possible is worthwhile. One of the parameters most looked for to define the quality status of a vineyard is the degree Brix of its grapes, a quantity usually determined by direct measurement.

Applications of a novel molecular phenology scale to align the stages of grape berry development

Phenology scales widely adopted by viticulturists (i.e., BBCH or modified E-L systems) are classification tools that describe seasonal and precisely recognized stages of fruit growth and development based on specific descriptors such as visual/physical traits or easy-to-measure compositional parameters.