https://doi.org/10.20870/IVES-TR.2020.3305 Does barrel size influence white wine aging quality? >>> White wine is increasingly aged in oak barrels alcoholic strength (12.9±0.1 %vol.), titratable and volatile to enhance its stability, aromatic complexity and acidity (2.9±0.1 and 0.3±0.0 g/L, respectively) remained organoleptic properties. Thus, this research aimed constant beyond the malolactic fermentation. As observed in Figure 1, wine color was as well not impacted by barrel to highlight chemical and sensory differences in size. In addition, no signs of oxidation nor browning were Sauvignon Blanc wines linked to barrel size. Oenological observed during aging for any of the wines analyzed. parameters, color, total phenolics and fruity aroma In the case of Fruité toasting, no significant differences were were not generally impacted by barrel size. Meanwhile, found between both barrel sizes regarding total phenolic content of wines throughout the whole experimentation. the smaller the barrel, the higher the extraction of 0,35 Meanwhile, the Épicé 225 L barrel (231 ± 3 mg GA/L oak woody volatiles. From an organoleptic point of 0,30 wine) led to a slightly higher total phenolic contentÉpicé toasting than view, Sauvignon Blanc varietal aromas and typicity the largest barrel size (214 ± 0,251 mg GA/L wine) of the seemed to be better preserved by 500 L barrels. <<< same toasting: the ratio of surface0,20 area to wine volume is 2 greater in the smallest barrel (0.90,15 m / hL wine for 225 L 2 Abs at 420 nm barrel and 0.7 m /hL wine for 5000,10 L barrel). The different To obtain a high quality aged wine, barrel choice is of behaviors observed for Epicé and FruitéÉpicé 225 LbarrelsÉpicé 500 L may be 0,05 great importance. Transfer of wood compounds into wine justified by the barrel toasting influence on phenolics 0,00 extractability from oak wood. After AF After MLF 2,5-months 5-months and micro-oxygenation that take place during barrel ageing ageing aging have a significant effect on phenolic composition and organoleptic perception of the final product. Both 0,35 0,35 processes lead to a greater aroma and flavor complexity, 0,30 0,30 Épicé toasting Fruité toasting and depend on several factors such as wood species and 0,25 0,25 origin, aging time, barrel size, toasting and manufacture1. As Emile Peynaud stated ‘Young wine develops more 0,20 0,20 0,15 0,15 Abs at 420 nm rapidly in small volume’. The smaller the barrel, the Abs at 420 nm greater the surface area to wine volume ratio and the 0,10 0,10 Épicé 225 L Épicé 500 L Fruité 225 L Fruité 500 L higher the oxygenation flow per wine volume unit. Thus, 0,05 0,05 even if aging time, barrel toasting, species and origin 0,00 0,00 After AF After MLF 2,5-months 5-months After AF After MLF 2,5-months 5-months of wood are the same, the aging process and the oak ageing ageing ageing ageing character of wine will differ depending on barrel size. Figure0,35 1. Evolution of wine color according to barrel size for both Épicé and Fruité toastings. No studies have addressed this issue for white wines, 0,30 even if aging them in oak barrels is becoming a common Fruité toasting practice in some winegrowing regions. Esters,0,25 synthesized during alcoholic fermentation and modulated0,20 during malolactic fermentation, are known to play an important role in the fruity nature of wines2. n Materials and methods 0,15 ThroughoutAbs at 420 nm the whole experimentation, similar contents 0,10 White wine (90 % Sauvignon Blanc, 5 % Sémillon and of these Fruitévolatile 225 L Fruité compounds500 L were found in wines from 5 % Muscadelle) considered in the present research was both0,05 barrel sizes. Thus, fruity character of wines was not 0,00 vinified in 2018 vintage in Château La Freynelle (Entre- impactedAfter AF by Afterbarrel MLF 2,5-months size. 5-months deux-Mers appellation). Alcoholic fermentation started in In contrast, a quite ageingdifferentageing woody aroma profile was stainless steel tanks and, at a density of 1040 g/L, wine obtained depending on the barrel volume (Figure 2). was transferred to barrels. All wooden containers used Specifically, a greater extraction of whiskeylactones, were made up of French oak from two species (95 % considered as main responsible for coconut, woody Quercus petraea and 5 % Quercus robur) by Nadalié and oak-like olfactory notes, was observed for wines cooperage (Ludon-Médoc, France). Barrels of two different aged in 225 L barrels. In the case of Épicé toasting, sizes (225 L and 500 L) and two different toastings (Épicé trans- whiskeylactone concentration was around 19-fold and Fruité) were considered (three different units per greater in wine from 225 L barrel than in wine from 500 L modality size-toasting). barrel. The same behavior was shown for Fruité toasting In order to highlight potential chemical and organoleptic in a lesser extent (a content from 3 to 4-fold higher in the differences linked to barrel size, phenolic composition, smallest barrel). fruity and woody aroma profiles and sensory properties With regard to the cis-whiskeylactone, only wines were determined. For this purpose, wine was sampled from 225 L barrels presented concentrations above its at the end of both alcoholic and malolactic fermentation, perception threshold (54 μg/L wine). Wines from 500 L and after 2.5- and 5-months aging. barrels exhibited values between 3- and 7-fold times lower. Consequently, a direct impact on woody perception of the n Impact on chemical composition final wine might be observed. Even if less noticeable, the same behavior as Regardless of barrel size and toasting, conventional whiskeylactones was displayed by vanillin, the main oenological parameters of wines such as pH (3.5±0.0), contributor to vanilla smell in wines. The set-up and launch of IVES Technical Reviews are supported by the LabEx COTE via its Transfer and valorization call for projects. The translation of this article into English was offered to you by Moët Hennessy. Exotic fruits After AF After MLF 2.5-months ageing 5-months ageing 7 180 6 Bitterness Cat's pee* 5 500 L 160 4 140 3 2 120 1 100 225 L *Palate volume 0 Woody 225 L 80 60 whiskylactone (µg/L whiskylactonewine) (µg/L - 40 trans A ci dity Oxydation 20 Epi cé toasting 225L 0 Typicity Epicé toasting 225L Epicé toasting 500L Fruité toasting 225L Fruité toasting 500L Epi cé toasting 500L 500 L After AF After MLF 2.5-months ageing 5-months ageing 120 ) 100 Exotic fruits 7 wine 6 80 Bitterness Cat's pee* 5 500 L (µg/L (µg/L 4 60 Perception 3 threshold (54 µg/L) 2 1 hiskylactone 40 w - 225 L Palate volume 0 Woody 225 L cis 20 0 Epicé toasting 225L Epicé toasting 500L Fruité toasting 225L Fruité toasting 500L A ci dity Oxydation Figure 2. Evolution of main woody aroma compounds of white wines according to barrel size for Fruité toasting 225L both Épicé and Fruité toastings. Typicity Fruité toasting 500L n Impact on organoleptic quality 500 L Sensory analyses were performed by a panel of 24 expert judges from the Institute of Vine and Wine Sciences of Figure 3. Sensory evaluation of white wines according to barrel size for both Épicé and Fruité the University of Bordeaux. Olfactory and gustative panel toastings. * indicates statistical significant differences between both barrel sizes at 5 % level. training was first conducted to familiarize the subjects with Sauvignon Blanc character, aroma recognition and wine studied white wines. Meanwhile, it was observed that taste. Sauvignon Blanc character was defined for this the extraction of woody aromas certainly depends on research according to the main odorant attributes of thiol the surface area to wine volume ratio: the smaller the compounds present in this grape variety: cat’s pee, exotic barrel, the higher the surface of wine-wood interaction fruits (grapefruit, passion fruit or lychee), and oxidation per unit of wine volume, and the greater the transfer notes (cooked potato, curry or walnut). of whiskeylactones and vanillin from wood to wine. Judges were able to distinguish wines according to barrel Regarding the sensory analyses, 500 L barrels seemed size. Differences detected between wines from 225 L to better preserve Sauvignon Blanc varietal aromas (cat’s and 500 L barrels were significantly related to cat’s pee, aromatic marker for Sauvignon Blanc typicity). pee notes (higher intensity for wines from 500 L barrels) Woody compounds, volatile or not, are transferred into and, in the case of Épicé toasting, also to palate volume the wine as it ages. Too much of these compounds might (greater for wine of 225 L barrel) (Figure 3). Furthermore, damage wine harmony, but just the right amount of wood even if the differences were not statistically significant, may significantly improve its quality. The goal is to choose judges generally perceived wines from 225 L barrels as the best surface/volume ratio as well as the best contact woodier and attributed to wines from 500 L barrels a time between oak and wine in order to enhance fruity higher Sauvignon Blanc typicity. According to the judges’ aromas, add structure and build the desired oak character evaluation, oak character was pleasantly present in all of the final wine. n wines, but better integrated into the aromatic bouquet of wines aged in 500 L barrels. María Reyes González-Centeno1,2,3, Cécile Thibon1,2, Pierre- As observed according to the judges, the larger the size Louis Teissedre1,2, Kleopatra Chira1, 2, 3 of the barrel, the greater the capacity to keep the typicity 1 Univ.