UPDATE

Number 1 – 2014

NEWS FLASH

❖ The Lalvin ICV oKay® winemaking yeast received an Innovation Award at the SITEVI Varietal Aromas Resulting 2013 international exhibition. Lalvin ICV oKay® is the result of collaborative research from Alcoholic and Malolactic by the scientific group of the Institut Coopératif du Vin (ICV), Lallemand, SupAgro and INRA Montpellier. The innovation relies Fermentations on successive back-crosses between a partic- he interaction between microorgan- ularly effective yeast strain from a winemak- isms and the must is a complex ing point of view and a yeast presenting a mechanism involving a multitude of very low capacity for producing such sulphur T substrates and products, including some that compounds as H S and SO . The outcome is 2 2 have major sensory impacts. The nutrients Lalvin ICV oKay®, which combines excellent present in the grape must (e.g., carbon, fermentation capacity with very low SO , 2 oxygen, nitrogen, sulphur and phosphorus H S and acetaldehyde production. Lalvin ICV 2 compounds, vitamins, minerals and trace oKay® is recommended for aromatic white elements) create the conditions necessary to and , where it reduces volatile ensure the proliferation of microorganisms. acidity levels, reveals aromatic esters and Particularly, microorganisms use the sugars enhances freshness and balance on the and amino acids, which have the metabolic palate. effect of producing multiple metabolites from ❖ The Lallemand App is now compatible non-volatile esters (mostly polyols and acids) with iPad and Android devices. Integrating and volatiles esters (e.g., alcohols, aldehydes all the functions offered for the iPhone, the and ketones, fatty acids, sulphur and phe- iPad and Android versions of the application nols), which also impact the aroma and the Figure 1. Carménère varietal put all the information you need regarding “bouquet du vin” (Swiegers et al. 2005). The norisoprenoid precursors, which encourage Lallemand fermentation products – from microorganisms interact with, notably, the the development of a rich aroma profile. wine yeast and bacteria, to their nutrients, various aroma precursors present in the grape The influence of the on the aroma protectors and enzymes – at your fingertips by targeting, more specifically, the glycosides, potential of was also and help you make the best selection. conjugated cysteine and the phenolic com- shown. For example, in the Casablanca val- pounds (Eglinton et al. 2004, and Dillon et ley (a temperate climate and later ), al. 2004). WINEMAKING UPDATE produces grapes that were two and four times This issue of Winemaking Update summarizes higher in 4-methyl-4-mercaptopentanone WINEMAKING UPDATE is published by the XXIVes Entretiens Scientifiques Lallemand. (4MMP) and 3-mercapto-hexanol (3MH) Lallemand to inform oenologists and These scientific meetings, held in 2013, dis- than those of Curicó valley, where it is very winemaking staff about the latest news cussed the impact of wine yeasts and bacteria hot and vines are planted very densely. on varietal aromas. and applications arising from research. To Other research has revealed that mechani- request previous issues, or to send your 1. The Aromatic Potential of cal harvesting causes a greater loss of aroma questions or comments, contact us at: Warm Climate Wines precursors than hand harvesting. At the Lallemand pre-fermentation stages, the thiol precursors Gordon Specht Professor Eduardo Agosin, from the Pontificia continue to degrade (figure 2). By comparing P.O. Box 5512 Universidad Católica de Chile, presented the measurements taken on the grapes at Petaluma CA 94955 U.S.A. a summary of his research team’s work on their delivery to the and in the final [email protected] aroma precursors. Yellow Muscat and Early wine, immediately after fermentation, we can White Muscat, two rather rare varieties in see that only 2% to 5% of the initial level of The technical information in WINEMAKING northern Chile, where (a young UPDATE is true and accurate at the time active and odorant thiols remain in the final with a fruity nose) is produced, are espe- wine. The level of the thiol precursors in the of publication. Due to the great diversity cially rich in terpene precursors. In the same of winemaking operations, all information grape transforming into free thiols is very region, the study of aroma potential on more low. Even though the yeasts, during fermen- and advice is provided with no guarantee than 50 samples of Muscat of or formal engagement. Lallemand products tation, release thiols, the concentration var- and Muscat Rosé revealed that these vari- ies considerably from one strain to another, are widely available through distribution etals are high in aglycones from the terpene and we observe a loss of 25% to 45% of the networks. To find your local distributor, family, as well as C13-norisoprenoids, which initial value. Understanding the evolution contact us at the above address. confer floral notes. Carménère (figure 1), the of the thiol precursors at the pre-fermenta- varietal emblematic of Chile, is high in C13- www.lallemandwine.com@ tion stage and during alcoholic fermentation Continued nies were identified and underwent analysis Free thiols Bound thiols Loss for similarities (ANOSIM), which revealed 100% that, objectively, for the 2010 ran- domly sampled fungal communities from ripe 25% 80% 34% grapes showed a much greater 45% difference than would be expected by chance 60% (R values are significant according to pairwise comparisons). The biodiversity of microor- 40% ganisms, linked to different regions and ter- Odour Units roirs, is still to be explored as much remains 20% unknown. 0% 3. Influence of Enzymes on the Delivery Racking Fermentation Aroma of Touriga -20% Nacional

Figure 2. Evolution of free and bound 3-mercapto-hexanol (3MH), as a percentage of total 3MH at delivery The “bergamot” aroma signature of the to the winery and during different stages of winemaking with Sauvignon Blanc grapes from Casablanca (2006 Touriga Nacional varietal is attributed to ter- harvest) penol, linalool and their acetates. Research by Frank Rogerson and Charles Symington (Symington Family Estates, Portugal) showed (AF) is essential to optimizing their impact yeasts, as well as their distribution in space the interest of pectolytic enzyme prepara- on the final quality of the Sauvignon Blanc and in time. For example, are the yeast spe- tions rich in ß-glucosidase activity on the wines, much more than seeking to increase cies associated with vines and wines the same level of key odorant molecules of Touriga their concentration in the grape. in every region of the world? If not, how and Nacional grapes. The red wines treated with to what extent do they differ from one region these preparations present a greater floral 2. How to Exploit the Microbial to another? Are yeasts involved in defining and citrus aroma complexity, which is main- Ecosystem of the Wine terroir? To better understand the distribu- tained throughout aging in bottles for 2.5 Professor Matthew R. Goddard, from the tion of yeasts in space and time and what years. These results suggest that not only University of Auckland, New Zealand, pre- links them to the vines and wines, Professor the terpenols, but other aglycone precursors sented concepts and techniques from the Goddard proposes sampling procedures, sta- as well, are released and play an important ecology of microorganisms, explaining their tistically useful tests and appropriate analysis role in the aroma complexity of the vari- particular interest in the field of . techniques. etal. should learn to master the Although we have considerable knowledge Figure 3 outlines observations from research potential of using enzymes by determining about different strains of Saccharomyces cere- by Gayevskiy and Goddard (2012) on six the appropriate dose and the best timing to visiae, there is still much to learn about located in three regions in northern obtain the desired wine style. the phenotypic and genetic diversity of New Zealand. During this study, 1,566 colo- The best moment to add an enzyme prepara-

800 700 600 500 400 300 200 100 PDMS µg/L equivalent to DMS/L to PDMS µg/L equivalent 0

Strain 6 Strain 5 Strain 6

Syrah must Yeast strain 5

Strain 5 + Fermaid E Strain 6 + Fermaid E Strain 5 + Fermaid E Strain 6 + Fermaid E Synthetic must MS120 Figure 3. Outline of observations from the study by Gayevskiy and Goddard (2012) on six vineyards Figure 4. Influence of the addition of Fermaid E on the consumption of potential dimethyl sulphide by differ- located in three regions in northern New Zealand ent strains of yeast during alcoholic fermentation 4.5

4.0 a 3.5 ab

3.0 bc bcd 2.5 cde 2.0 def def efgh defg 1.5 fghi efghi efghi

Glutathione (μg/L) Glutathione ghi fghi ghi 1.0 ghi hi i hi i 0.5

0 Yeast 1 Yeast 2 Yeast 3 Yeast 4 Yeast 5 Yeast 6 Yeast 7 Yeast 8 Yeast 9 Yeast Yeast 10 Yeast 11 Yeast 12 Yeast 13 Yeast 14 Yeast 15 Yeast 16 Yeast 17 Yeast 18 Yeast 19 Yeast 20 Yeast

Yeast Strain

Figure 5. Reduced glutathione (GSH) concentrations at the end of alcoholic fermentation after adding 20 different commercial Saccharomyces cerevisiae strains Vertical bars denote 95% confidence intervals for the means. Letters indicate significant differences on a 5% (p<0.05) significance level (Kritzinger et al. 2013b, reproduced with the permission of the Australian Journal of Grape and Wine Research). tion high in glycosidases is following sulphit- et du Vin [IFV]) focused on dimethyl sul- maturity, production site, foliar spraying and ing and after (MLF), phide (DMS), associated with the percep- varietal) that influence the potential DMS when the is ready to evaluate the tion of herbaceous notes, truffle, cabbage, (PDMS), of which the most important are aroma impact of AF and MLF on the wine undergrowth and green olive in wine aromas, maturity and the varietal. However, dur- profile, and to judge the remaining need to where it also enhances the fruity character. ing the study, the fermentation parameters enhance the complexity of the wine. Most of the DMS disappears with the CO2 appeared to have a more determining impact during fermentation; the levels at the time on the concentration of PDMS at racking. 4. Managing the Dimethyl Sulphide of racking are generally situated under the At the pre-fermentation stages of operations, Concentration in Bottles perception threshold. The goal of Dagan such as macerating on skins and stabulation The work of Laurent Dagan (Nyséos) and and Schneider is to identify and evaluate on lees, the solution for extracting PDMS, Rémi Schneider (Institut Français de la Vigne the winegrowing factors (e.g., hydric stress, located mainly in the skin, remains to be

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Concentration (mg/L) Concentration 100

75

50 Control yeast

Mix Oenococcus oeni 2 Oenococcus oeni 1

Figure 6. Total ester concentration in wine after malolactic fermentation using 14 different yeast strains and three lactic acid bacteria starter cultures in co-inoculation and a control that was not inoculated for MLF, in a 2011 (Schöltz 2013) explored. The fermentation conditions (e.g., centrations. Twenty commercial strains of ria generally present in wine, Oenococcus oeni yeast strains, nitrogen nutrition, fermenta- Saccharomyces cerevisiae were inoculated into is the bacteria best adapted to this hostile tion temperature, fermentation adjuvants) synthetic solutions of grape juice, and GSH environment and the one most often utilized. also have an impact on PDMS. The choice of levels were measured after AF. Significant However, Lactobacillus plantarum is the one yeast strain and the management of nitrogen differences were observed among the results most often utilized in fermentations destined supplementation, notably, are the key param- obtained for the different strains (figure 5). for high pH wines and for co-inoculation. eters to limit PDMS consumption by the Sauvignon juices containing various levels of L. plantarum produces different ester concen- yeast during fermentation (figure 4). GSH were also analysed. During AF, signifi- trations. What’s more, this bacteria has the Two strains of yeasts, L5 and L6, were inocu- cant trends appeared regarding the evolution capacity to release monoterpenes through lated into MS120 synthetic must and a of GSH, according to the yeast strain utilized its -glycosidase activity. The aroma profile must with and without the addition and the initial GSH concentration in the depends on the timing of inoculation. The of Fermaid E, a nitrogen nutrient designed juice. Sometimes the GSH concentration winemaker can get the most from all these to prevent a possible deficiency in the must. increased over the initial level, which appears factors to adapt the wine style to consumer Adding this nutrient (5 g/hL) contributed to to indicate that the GSH is synthesized and preferences. preserving a part of the PDMS. In the must secreted by the yeast. 7. Volatile Compounds and the with the L5 yeast, the percentage of residual Commercial preparations of GSH-enriched Perception of the Aroma PDMS increased from 12% to 29%, which inactivated dry yeasts (GSH-IDY) were Attributes of Wine shows that the addition of nitrogen has a pos- added at different stages of fermentation. The itive influence on the consumption of PDMS antioxidant potential of these preparations is Dr. Ana Escudero, from the Universidad de by the yeast. With L6, the increase was not highly variable. The analyses showed that the Zaragoza, Spain, reviewed current knowledge as marked, which confirms the specificity of addition can lead to higher GSH levels in the and presented the latest findings on the certain strains to assimilate the PDMS. wines, as long as the addition is made during aroma chemistry of wine. Indeed, the mastering of DMS in the wine the first third of fermentation. Her research focuses on the key odour can also occur through the management of The mechanism by which these preparations molecules perceived in wine. The aromas PDMS during blending. As for aging, the influence the yeast metabolism and contrib- extracted through gas chromatography-mass correlations obtained allow us to predict the ute to increasing GSH levels, as well as their spectrometry (GC-MS) are the basis for a list approximate percentage of releasable DMS, impact of the sensory profile of the wine, in which they are divided into two groups – but this model must be refined through better remains to be explored. qualitative aromas and quantitative aromas. knowledge of the influence of storage condi- A series of sensory analyses followed with the tions on the percentage of DMS released. 6. The Impact of Wine Bacteria purpose of reconstructing the wine aroma, Already, new data on managing DMS levels and Different Malolactic which gave rise to a new classification system. in wine allow us to imagine integrated pro- Fermentation Scenarios on According to this system, all the wines share duction processes better adapted to the style the Aroma Profile a common basic aroma structure that includes of the final product. ethanol and 27 aroma compounds, most Professor Maret du Toit, from the University of which are by-products of fermentation. 5. Glutathione – An Important of Stellenbosch, South Africa, presented the When combined, these compounds release Antioxidant results of trials carried out in collaboration the aroma characteristic of wine and form an with Caroline Knoll and Doris Rauhut, from E. C. Kritzinger presented a study she con- “aroma buffer” that has the capacity to buffer the Geisenheim Institute in Germany, for ducted in collaboration with Dr. Wessel du several existing odorants, particularly those the purpose of evaluating the impact of wine Toit, C. Coetzee, and M. Gabrielli, from the associated with fruity notes. The ability of the bacteria and different MLF scenarios on wine University of Stellenbosch, South Africa, different aromatic chemical compounds to aromas. and with D. Fracassetti, from the University break this olfactory buffer and modulate the of Milan, Italy, with the aim of better under- Changes to the aroma profile during MLF aroma profile of the wine, as well as the link standing the evolution of glutathione (GSH) depend on different factors, such as the between the aroma note transmitted and the during AF and verifying the effects of a wide varietal and the aroma precursors, and on aroma of the chemical compound from which range of oenological factors on the levels of specific parameters of the wine (notably it results, are the basis for determining the GSH in Sauvignon wine, which is subject the pH and ethanol level, which exerts a contribution of the aroma compounds in the to oxidation. GSH has a protective effect of strong influence on the bacterial viability aroma profile of the wine. Thus, a compound the wine aroma during aging. The researchers and activity). The choice of yeast strain for could be qualified as a genuine (high-impact) examined the effects of adding various com- co-inoculation also has a major impact on contributor, a major contributor, a secondary binations of O2 and SO2 to the must on the the final aroma and style of the wine (figure (subtle) contributor, an aroma enhancer or GSH concentration in the must and in the 6). In addition, wine bacteria synthesize and an aroma depressor in the wine. Sauvignon wine. hydrolyze the aromatic esters in various ways The wine made with oxidized juice and no during MLF, according to the strain utilized. Among the four species of oenological bacte- SO2 presented significantly lower GSH con-

TO SUMMARIZE...

All new knowledge, every discovery related to wine aromas and the multiple factors that modulate their expression and participate in their balance make us realize the remarkable complexity of this field of research. The perspectives offered by current research are fascinating. The constant improving of our understanding of the effects of microorganisms and their derivatives on the varietal aromas of wine generates the ideas and the tools that will help winemakers modulate and define the style desired for their final product. References available upon request. You can obtain a copy of the proceedings of the XXIVes Entretiens Scientifiques Lallemand from your Lallemand representative.