 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

Climate, Viticulture, and Wine … my how things have changed!

The planet is warmer than at any time in our recorded past and increasing greenhouse emissions and persistence in the climate system means that continued warming is highly likely. Climate change has already altered the basic framework of growing grapes for wine production worldwide and will likely continue to do so for years to come. The wine sector can continue to play an important role in leading the agricultural sector in addressing climate change. From developing on…

Influence of agronomic practices in soil water content in mid-mountain vineyards

In the context of LIFE project MIDMACC (LIFE18 CCA/ES/001099), several pilots have been installed in vineyards in mid mountain areas of Catalonia (NE Spain) to test well stablished agronomic practices to increase the adaptation of Mediterranean mid mountain to climate change. Soil water content (SWC) at three different depths (15, 30 and 45cm) was measured in continuum from August 2020. One pilot (WC) included a well-established green cover (GC), a new GC (NC) and a conventional soil management (CM, tilling+herbicides). NC presented an intermediate state between WC and CM, responding similarly to CM in autumn but quickly reaching similar SWC to WC, then following the same evolution till next spring, with CM presenting lower values along autumn and winter. Then vegetation activation decreased SWC in all plots, (much slower in CM, lacking GC). Sensibility to spring rains is again intermediate for NC, which joins SWC evolution of CM by the end of spring till next autumn. It is expected that NC will resemble WC more and more as its GC develops. In the pilot combining vine training (VSP vs Gobelet) and hillside management (slope vs terrace), no clear pattern could be related with these conditions. However, both terraces seem to be more sensitive to spring rains. A third pilot included new vineyards (7 and 1 year old). In the new vineyard (N), higher canopy development, a spontaneous green cover and row straw resulted in a slower SWC dynamic, not so sensitive to rains but conserving more soil water in spring and most of summer, even with presumably a higher water extraction by vines. In the newest vineyard (VN) the deepest sensor is still sensitive to rain events all over the year and SWC is always highest at this depth, revealing small water capture by vines.

Spatiotemporal patterns of chemical attributes in Vitis vinifera L. cv. Cabernet Sauvignon vineyards in Central California

Spatial variability of vine productivity in winegrapes is important to characterise as both yield and quality are relevant for the production of different wine styles and products. The objectives were to understand how patterns of variability of Cabernet Sauvignon fruit composition changed over time and space, how these patterns could be characterised with indirect measurements, and how spatial patterns of the variation in fruit compositional attributes can aid in improving management. Prior to the 2017 vintage, 125 data vines were distributed across each of four vineyards in the Lodi American Viticultural Area (AVA) of California. Each data vine was sampled at commercial harvest in 2017, 2018, and 2019. Yield components and fruit composition were measured at harvest for each data vine, and maps of yield and fruit composition were produced for eight ‘objective measures of fruit quality’: total anthocyanins, polymeric tannins, quercetin glycosides, malic acid, yeast assimilable nitrogen, β-damascenone, C6 alcohols and aldehydes, and 3-isobutyl-2-methoxypyrazine. Patterns of variation in anthocyanins and phenolic compounds were found to be most stable over time. Given this relative stability, management decisions focused on fruit quality could be based on zonal descriptions of anthocyanins or phenolics to increase profitability in some vineyards. In each vineyard, dormant season pruning weights and soil cores were collected at each location, elevation and soil apparent electrical conductivity surveys were completed, and remotely sensed imagery was captured by fixed wing aircraft and two satellite platforms at major phenological stages. The data collected were used to develop relationships among biophysical data, soil, imagery, and fruit composition. The standardised and aggregated samples from four vineyards over three seasons were included in the estimation of ‘common variograms’ to assess how this technique could aid growers in producing geostatistically rigorous maps of fruit composition variability without cumbersome, single season sampling efforts.

Inhibition of Oenococcus oeni during alcoholic fermentation by a selected Lactiplantibacillus plantarum strain

The use of selected cultures of the species Lactiplantibacillus plantarum in Oenology has grown in prominence in recent years. While initial applications of this species centred very much around malolactic fermentation (MLF), there is strong evidence to show that certain strains can be harnessed for their bio-protective effects. Unwanted spontaneous MLF during alcoholic fermentation (AF), driven by rogue Oenococcus oeni, is a winemaking deviation that is very difficult to manage when it occurs. This work set out to determine the efficacy of one particular strain of Lactiplantibacillus plantarum(Viniﬂora® NoVA™ Protect), against this problem in Cabernet Sauvignon must. The work was carried out at commercial scale and in a winery environment and compared the bio-protective culture with the more traditional approach of reducing must pH by the addition of tartaric acid. The combination of both was also investigated. The concentration of both Oenococcus oeni and Lactiplantibacillus plantarum was determined using qPCR. The adventitious Oenococcus oeni showed the most growth during AF in the control wine, whereas in the wines treated with Lactiplantibacillus plantarum a bacteriostatic effect against this species was observed. This effect was comparable to the wines treated with tartaric acid. This has particular commercial relevance for controlling the flora in musts with high pH, or when the addition of tartaric acid is either not permitted or is prohibitive for other reasons.

‘Cabernet Sauvignon’ (Vitis vinifera L.) berry skin flavonol and anthocyanin composition is affected by trellis systems and applied water amounts

Trellis systems are selected in wine grape vineyards to mainly maximize vineyard yield and maintain berry quality. This study was conducted in 2020 and 2021 to evaluate six commonly utilized trellis systems including a vertical shoot positioning (VSP), two relaxed VSPs (VSP60 and VSP80), a single high wire (SH), a high quadrilateral (HQ), and a guyot (GY), combined with three levels of irrigation regimes based on different crop evapotranspiration (ETc) replacements, including a 25% ETc, 50% ETc, and 100% ETc. The results indicated SH yielded the most fruits and accumulated the most total soluble solids (TSS) at harvest in 2020, however, it showed the lowest TSS in the second season. In 2020, SH and HQ showed higher concentrations in most of the anthocyanin derivatives compared to the VSPs. Similar comparisons were noticed in 2021 as well. SH and HQ also accumulated more flavonols in both years compared to other trellis systems. Overall, this study provides information on the efficacy of trellis systems on grapevine yield and berry flavonoid accumulation in a currently warming climate.