 IVES 9 IVES Conference Series 9 Macrowine 9 Macrowine 2021 9 Chemical diversity of 'special' wine styles: fortified wines, passito style, botrytized and ice wines, orange wines, sparkling wines 9 Comparison of two procedures to measure foamability from sparkling base wines supplemented with acacia gums

Comparison of two procedures to measure foamability from sparkling base wines supplemented with acacia gums

Abstract

In sparkling wines, foam is a relevant aspect whose measurement method could affect the results. The shaking test (ST) is a simple method measuring foamability1,2. But, unlike the most used and classical sparging-gas method (the so-called Mosalux; MOS)3, the amount of gas introduced is not controlled. MOS is, however, longer and needs more complex equipment. Our work compares both methods trying to demonstrate that ST can be an alternative and reliable method easily used by winemakers and enological laboratories.Eight base wines were elaborated by the traditional method, treated with bentonite, stirred and filtered. The origins of three base wines were three different regions from Spain (using Moscatel and Macabeo grapes). The other five were elaborated in the French region of Champagne (using Chardonnay and Pinot noir grapes). Four Acacia gums fractions were separately added to two selected wines (one French wine and one Spanish wine). These two (six modalities: control, bentonite-treated and gums fractions-treated wines; n=12) and the other six wines (two modalities: control and bentonite-treated wines; n’=12) were analyzed by MOS and ST. In this way the differences of wines were not only caused by the origin and by the cultivar but also by varying oenological techniques, ensuring a great variability of samples. Using MOS, wine was in a glass cylinder with a frit at the bottom injecting CO2. The Maximum Foam Height (HM-MOS) and the Foam Stability Height (HS-MOS) were measured. In ST, wine in tubes was strongly hand-shaken. The foam height was measured at 5 sec. (ST5) and every 10 sec. (ST10, ST20…) during 90 seconds (all in triplicate).ST required six times less amount of wine and gum fractions than MOS. The Maximum Foam Height by ST (HM-ST) was always reached at ST5 (closely followed by ST10). The foam stability period (when foam height was not statistically different to the last measure) always started before or just at ST70. In all modalities of both selected wines, HM-MOS and HM-ST presented similar ANOVA-statistical relationships. However, HS-MOS and ST90 were statistically related only in one selected wine. Multiple regression analyses were performed trying to know if some correlation could be established between (i) the foam height values at T5 and T10 by ST and (ii) the HM-MOS of 24 varying wines, as well as between (I) the foam height values at T70 and T90 by ST and (II) the HS-MOS. T5 and T10 were selected as the two moments presenting the two higher foam height values. T70 and T90 were selected as the two moments when the foam stability period began and finished. Multiple Regressions showed that HM-MOS correlated with ST5-ST10, and HS-MOS with ST70-ST90 (R2>70%; p

DOI:

Publication date: September 15, 2021

Issue: Macrowine 2021

Type: Article

Authors

Thierry Doco

UMR-1083/SPO, INRAE-Montpellier, France,Rafael Apolinar-Valiente, UMR-1208/IATE, Montpellier SupAgro, France. Thomas Salmon, LOCA, Université de Reims, France. Pascale Williams, UMR-1083/SPO, INRAE-Montpellier, France. Michaël Nigen, UMR-1208/IATE, Université Montpellier, France. Christian Sanchez, UMR-1208/IATE, Université Montpellier, France. Richard Marchal, LVBE, Université de Haute-Alsace, Colmar, France.

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Keywords

sparkling base wine; foamability; shaking test; gas-sparging method; maximum foam height; foam stability height

Citation

Effect of fertigation strategies to adapt PGI Côtes de Gascogne production to hot vintage

The development of fertigation could be a possible solution to adapt PGI Côtes de Gascogne (south-western France) wine production to climate change. The goal would be to limit the negative effects of water stress on yield performance expectation (around 15 tons per hectare) and to make the use of fertilizers more efficient. This study aimed to compare the effects of three strategies of water and minerals supply on grapes and wines qualities. Two fertigation practices were compared to a rainfed control which is the current standard of the local grape growing production. The fertilizers (nitrogen and potassium) were (i) fully brought by irrigation pipe during the season, (ii) partially brought by irrigation pipe and partially on the soil or (iii) fully brought on the soil at the beginning of the season for the non-irrigated control (local standard). The trial was run on cv. Colombard trained on spur pruned with vertical shoot positioning system on a sandy-silty-clay soil over the 2020 vintage which was particularly hot for the region. Moderate to strong water deficit appeared during the growing period of the berries and held on after veraison. Irrigation strategies allowed for maintaining grapevine without water deficit and being significantly different from the control water status. Grapevine with fully or partial fertigation strategies produced 25% more yield mainly due to the increase of the bunch weight. Also, the fully fertigation showed the best ratio between yield and maturity and brought 30% less of fertilizers (both nitrogen and potassium) than the two other strategies. Finally, the analysis of aromatic compounds in Colombard wines, varietal thiols family, showed the same level of concentrations for the 3 treatments, confirming that the yield performance did not impact the aromatic potential in this trial.

Adaptability of grapevines to climate change: characterization of phenology and sugar accumulation of 50 varieties, under hot climate conditions

Climate is the major factor influencing the dynamics of the vegetative cycle and can determine the timing of phenological periods. Knowledge of the phenology of varieties, their chronological duration, and thermal requirements, allows not only for the better management of interventions in the vineyard, but also to predict the varieties’ behaviour in a scenario of climate change, giving the wine producer the possibility of selecting the grape varieties that are best adapted to the climatic conditions of a certain terroir. In 2014, Symington Family Estates, Vinhos, established two grape variety libraries in two different places with distinctive climate conditions (Douro Superior, and Cima Corgo), with the commitment of contributing to a deeper agronomic and oenological understanding of some grape varieties, in hot climate conditions. In these research vineyards are represented local varieties that are important in the regional and national viticulture, but also others that have over time been forgotten — as well as five international reference cultivars. From 2017 to 2021, phenological observations have been made three times a week, following a defined protocol, to determine the average dates of budbreak, flowering and veraison. With the climate data of each location, the thermal requirements of each variety and the chronological duration of each phase have been calculated. During maturation, berry samples have been gathered weekly to study the dynamics of sugar accumulation, between other parameters. The data was analysed applying phenological and sugar accumulation models available in literature. The results obtained show significant differences between the varieties over several parameters, from the chronological duration and thermal requirements to complete the various stages of development, to the differences between the two locations, confirming the influence of the climate on phenology and the stages of maturation, in these specific conditions.

Mobile device to induce heat-stress on grapevine berries

Studying heat stress response of grapevine berries in the field often relies on weather conditions during the growing season. We constructed a mobile heating device, able to induce controlled heat stress on grapes in vineyards. The heater consisted of six 150 W infrared lamps mounted in a profile frame. Heating power of the lamps could be controlled individually by a control unit consisting of a single board computer and six temperature sensors to reach a pre-set temperature. The heat energy applied to individual berries within a cluster decreases by the squared distance to the heat source, enabling the establishment of temperature profiles within individual clusters. These profiles can be measured by infrared thermography once a steady state has been reached. Radiant flux density received by a berry depending on the distance was calculated based on a view factor and measured lamp surface temperature and resulted to 665 Wm-2 at 7cm. Infrared thermography of the fruit surface was in good agreement with measurements conducted with a thermocouple inserted at epidermis level. In combination with infrared thermography, the presented device offers possibilities for a wide range of applications like phenotyping for heat tolerance in the field to proceed in the understanding of the complex response of plants to heat stress. Sunburn necrosis symptoms were artificially induced with the aid of the device for cv. Bacchus and cv. Sylvaner in the 2020 and 2021 growing season. Threshold temperatures for sunburn induction (LT5030min) were derived from temperature data of single berries and visual sunburn assessment, applying logistic regression. A comparison of threshold temperatures for the occurrence of sunburn necrosis confirmed the higher susceptibility of cv. Bacchus. The lower susceptibility of cv. Sylvaner did not seem to be related to its phenolic composition, rendering a thermoprotective role of berry phenolic compounds unlikely.

Local adaptation tools to ensure the viticultural sustainability in a changing climate

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