Macrowine 2021
IVES 9 IVES Conference Series 9 Wine archeochemistry: a multiplatform analytical approach to chemically profile shipwreck wines

Wine archeochemistry: a multiplatform analytical approach to chemically profile shipwreck wines

Abstract

AIM: The Cape of Storms (also known as Cape of Good Hope) is renowned for harbouring a multitude of shipwrecks due to the inherent treacherous coastline and blistering storms. One such shipwreck is the English East Indiaman Colebrooke, wrecked in False Bay, South Africa, in 1778. A discovery on the shipwreck was a shipment of wine of unknown origin and style, possibly Madeira as it was known that the English East India Company often purchased wine from there but this was not mentioned in the ship’s log. As the wreck was exploited by treasure hunters, very little contextual information is known. To further expand the sample pool with more examples of old wine, we have included another sample recovered from the wreck of the SS Maori sunk in 1909. Additionally, three samples of (old) wines stored in vinotheque conditions were included: a Château d’Yquem (1918 vintage) and two Château Margaux (1984).

METHODS: A minimal volume of wine (<50 mL) was analysed using untargeted analyses (GC-MS, LC-HRMS and NMR spectroscopy), metals (ICP-MS/OES), and sugars and organic acids (HPLC-DAD-RID). Important volatile aroma compounds were identified by HS-SPME-GCMS and their identification confirmed using Wiley/NIST libraries and RI. A screening exercise was performed by experienced researchers to sensorially evaluate the possible wine-like aromas.

RESULTS: Unexpected chemical characteristics regarding the metal concentrations, sugar and acid composition as well as the aroma profile were found. Compared to current export regulations, the levels of heavy metals were considerably higher, possibly due to the bottle glass composition and leaching over time. The untargeted analyses showed various compounds including fermentation-derived products (esters, alcohols, aldehydes and fatty acids), terpenoids (linalool, fenchone) and “woody” compounds (furfural and guaiacol). Incredibly, some of the samples still presented wine-like features related to aroma both in the chemical and the sensory evaluation. 

CONCLUSIONS

Unlike other work where the source and/or type of beverage recovered from shipwrecks were known, and with a limited volume of sample, we could still obtain results providing interesting “chemical snapshots” of old wines using advanced analytical and spectroscopic techniques. Combining new technology platforms in analytical chemistry can provide valuable insight into the composition of wines recovered from shipwrecks with the help of maritime archaeologists. Including analyses such as X-ray diffraction on the bottles can assist in tracing more information about the sources of heavy metal content and possibly even the origin of the wines.

DOI:

Publication date: September 13, 2021

Issue: Macrowine 2021

Type: Article

Authors

Astrid Buica

South African Grape and Wine Research Institute, Department of Viticulture and Oenology, Stellenbosch University, South Africa,Cody, WILLIAMS, Department of Viticulture and Oenology, Stellenbosch University, South Africa Jaco, BOSHOFF, Iziko Museums of South Africa, Maritime Archaeology Unit, Research and Exhibitions, Cape Town, South Africa Wendy, BLACK, Iziko Museums of South Africa, Archaeology Unit, Research & Exhibitions Department, Cape Town, South Africa Valeria, PANZERI, Department of Viticulture and Oenology, Stellenbosch University, South Africa

Contact the author

Keywords

marine archeology, shipwreck, untargeted analyses, metals, sugars and organic acids, sensory screening

Citation

Related articles…

Influence of weather and climatic conditions on the viticultural production in Croatia

The research includes an analysis of the impact of weather conditions on phenological development of the vine and grape quality, through monitoring of four experimental cultivars (Chardonnay, Graševina, Merlot and Plavac mali) over two production years. In each experimental vineyard, which were evenly distributed throughout the regions of Slavonia and The Croatian Danube, Croatian Uplands,

Towards a regional mapping of vine water status based on crowdsourcing observations

Monitoring vine water status is a major challenge for vineyard management because it influences both yield and harvest quality. It is also a challenge at the territorial scale for identifying periods of high water restriction or zones regularly impacted by water stress. This information is of major importance for defining collective strategies, anticipating harvest logistic or applying for irrigation authorisation. At this spatial scale, existing tools and methods for monitoring vine water status are few and often require strong assumptions (e.g. water balance model). This paper proposes to consider a collaborative collection of observations by winegrowers and wine industry stakeholders (crowdsourcing) as an interesting alternative. Indeed, it allows the collection of a large number of field observations while pooling the collection effort. However, the feasibility of such a project and its interest in monitoring vine water status at regional scale has never been tested.

The objective of this article is to explore the possibility of making a regional map of vine water status based on crowdsourcing observations. It is based on the study of the free mobile application ApeX-Vigne, which allows the collection of observations about vine shoot growth. This information is easy to collect and can be considered, under certain conditions, as a proxy for vine water status. This article presents the first results obtained from the nearly 18,000 observations collected by winegrowers and wine industry stakeholders during 2019, 2020 and 2021 seasons. It presents the vine shoot growth maps obtained at regional scale and their evolution over the three vintages studied. It also proposes an analysis of the factors that favoured the number of observations collected and those that favoured their quality. These results open up new perspectives for monitoring vine water status at a regional scale but above they provide references for other crowdsourcing projects in viticulture.

Leaf vine content in nutrients and trace elements in La Mancha (Spain) soils: influence of the rootstock

The use of rootstock of American origin has been the classic method of fighting against Phylloxera for more than 100 years. For this reason, it is interesting to establish if different rootstock modifies nutrient composition as well as trace elements content that could be important for determining the traceability of the vine products. A survey of four classic rootstocks (110-Richter, SO4, FERCAL and 1103-Paulsen) and four new ones (M1, M2, M3 and M4) provided by Agromillora Iberia. S.L.U., all of them grafted with the Tempranillo variety, has been carried out during 2019. The eight rootstocks were planted in pots of 500 cc, on three soils with very different characteristics from Castilla-La Mancha (Spain). In the month of July, the leaves were collected and dried in a forced air oven for seven days at 40ºC. Then, the samples were prepared for the analysis determination, carried out by X-Ray fluorescence spectrometry. The results obtained showed that in the case of content in mineral elements in leaf, separated by soil type, we can report the importance of few elements such as Si, Fe, Pb and, especially, Sr. The rootstock does not influence the composition of the vine leaf for the studied elements that are the most important in determining the geochemical footprint of the soil. The influence of the soil can be discriminated according to some elements such as Fe, Pb, Si and, especially, Sr.

Variations of soil attributes in vineyards influence their reflectance spectra

Knowledge on the reflectance spectrum of soil is potentially useful since it carries information on soil chemical composition that can be used to the planning of agricultural practices. If compared with analytical methods such as conventional chemical analysis, reflectance measurement provides non-destructive, economic, near real-time data. This paper reports results from reflectance measurements performed by spectroradiometry on soils from two vineyards in south Brazil. The vineyards are close to each other, are on different geological formations, but were subjected to the same management. The objective was to detect spectral differences between the two areas, correlating these differences to variations in their chemical composition, to assess the technique’s potential to predict soil attributes from reflectance data.To that end, soil samples were collected from ten selected vine parcels. Chemical analysis yield data on concentration of twenty-one soil attributes, and spectroradiometry was performed on samples. Chemical differences significant to a 95% confidence level between the two studied areas were found for six soil attributes, and the average reflectance spectra were separated by this same level along most of the observed spectral domain. Correlations between soil reflectance and concentrations of soil attributes were looked for, and for ten soil traits it was possible to define wavelength domains were reflectance and concentrations are correlated to confidence levels from 95% to 99%. Partial Least Squares Regression (PLSR) analyses were performed comparing measured and predicted concentrations, and for fifteen out of 21 soil traits we found Pearson correlation coefficients r > 0.8. These preliminary results, which have to be validated, suggest that variations of concentration in the investigated soil attributes induce differences in reflectance that can be detected by spectroradiometry. Applications of these observations include the assessment of the chemical content of soils by spectroradiometry as a fast, low-cost alternative to chemical analytical methods.

Climate change impacts: a multi-stress issue

With the aim of producing premium wines, it is admitted that moderate environmental stresses may contribute to the accumulation of compounds of interest in grapes. However the ongoing climate change, with the appearance of more limiting conditions of production is a major concern for the wine industry economic. Will it be possible to maintain the vineyards in place, to preserve the current grape varieties and how should we anticipate the adaptation measures to ensure the sustainability of vineyards? In this context, the question of the responses and adaptation of grapevine to abiotic stresses becomes a major scientific issue to tackle. An abiotic stress can be defined as the effect of a specific factor of the physico-chemical environment of the plants (temperature, availability of water and minerals, light, etc.) which reduces growth, and for a crop such as the vine, the yield, the composition of the fruits and the sustainability of the plants. Water stress is in many minds, but a systemic vision is essential for at least two reasons. The first reason is that in natural environments, a single factor is rarely limiting, and plants have to deal with a combination of constraints, as for example heat and drought, both in time and at a given time. The second reason is that plants, including grapevine, have central mechanisms of stress responses, as redox regulatory pathways, that play an important role in adaptation and survival. Here we will review the most recent studies dealing with this issue to provide a better understanding of the grapevine responses to a combination of environmental constraints and of the underlying regulatory pathways, which may be very helpful to design more adapted solutions to cope with climate change.