PHENOLIC SECRETS: Time: 9:45am – 10:45am Moderator: Tinus Els Exploring Finishing Tannins in Maturation and Blending Time: 9:45am – 10:45am Moderator: Tinus Els Speakers: Adolfo Alarcon – Winemaker / Technical Liason, Trinchero Family Wine Estates Sabrina Lueck – Instructor of Enology, Walla Walla Community College Richard Mansfield – North American Winemaker, Winery Exchange Bernard Pradel – Co-Founder, Toasted Oak Co.

Finishing Tannins: Function, Fates, and Flavors Alternate Title: “Sabrina reads literature so you don’t have to!” Sabrina Bitz Lueck Walla Walla Community College / College Cellars

Today Difference between fermentation, ageing, and finishing tannins Difference between hydrolysable and condensed tannins Different hydrolysable tannin species What do they do? Different oak aroma species Compare 4 finishing tannin products using ETS Laboratories data

Product Classes (Some Generalizations) Fermentation Tannin Ageing Tannin Finishing Tannin Tannin source Can include grape, oak, chestnut, exotic wood, gall nut Mainly oak, occasionally grape Protein reactivity Yes (laccase protection) Yes No (or low) Antioxidant activity Color stabilization Some (maybe)

Grape Tannins: Non-Hydrolysable (Condensed) Tannins Flavonoids (specifically procyanidins) Origin Grape seeds, skins, and stems Non-toasted oak, chestnut or “exotic” woods, gall nuts Function Provides tannic structure Monomers are bitter and astringent Polymers are not bitter, but astringent Anti-oxidant activity – reacts directly w/ O2 Maybe control expression of reduced sulfur aromas? Quinone capture of volatile thiols Fate Buddying up with anthocyanins or other condensed tannins Precipitation during extended ageing (oxidation involved) Condensed tannin molecule (Scollary, 2010)

Oak Tannins: Hydrolysable Tannins Non-flavonoid, ellagitannins and gallotannins Origin Toasted oak and gall nut Gallic acid can also come from stems Function Sensory impact is controversial Maybe synergistic impact Doesn’t react well with salivary proteins No “drying” mouthfeel? Reacts pretty well with other stuff! Fate To hydrolyze (and react) Ellagitannin → ellagic acid Gallotannin → gallic acid Vescalagin molecule (Waterhouse, 2002)

Function/Fate: Compound Capture A few ellagitannins can capture grape or fermentation derived nucleophiles Sulfur based – e.g. 3-sulfanylhaxan-1-ol “grapefruit / tropical”, methanethiol “rotten cabbage” Anthocyanins – oenin forms anthocyano- ellagitannin, bathychromatic shift + H2O2 + O2 → → (Chatonnet et al., 1992)

Reduction to “Roasted” Oak aromatic aldehydes can perform more than just aroma masking. Furfural formed from oak wood hemicellulose degradation during toasting. Chemical reaction occurs. + H2S → Furfural “sweet” “caramel-like” “toast” Furfurylthiol “roasted”

Things on the ETS Oak Phenolics Panel Gallic acid – antioxidant, derived from gallotannins, little/no sensory effect Ellagic acid – antioxidant, derived from ellagitannins, little/no sensory effect Vescalin and castalin – derived from vescalagin and castalagin, react w/ nucleophiles (reduced sulfur and others) Vescalagin and castalagin – reacts w/ nucleophiles (reduced sulfur and others) Complex ellagitannins – other stuff, compounds that “read” as non condensed tannins, likely ellagitannins bound to other ellagitannins Total ellagitannins – all the stuff!

Things on the ETS Oak Aroma Panel Furfural + 5-methylfurfural – “butterscotch” “caramel” cis-oak lactone + trans-oak lactone – “raw oak” “coconut” Guaiacol + 4-methylguaiacol – “charred” “smoky” “spicy” Eugenol + Isoeugenol – “clove” Vanillin – “vanilla”

Oak Aromas: Lignin Derived Flavors Guiacol “charred” Eugenol “clove” Lignin fills in spaces between other polysaccharides in cell walls. Provides mechanical strength. Lignin fragment 4-methylguiacol “smoky” “spicy” Vanillin “vanilla” (structures from Gavin Sacks, Cornell University)

Oak Aromas: Hemicellulose Derived Flavors Hemicellulose is a long chain of sugar Breakdown products taste/smell like cooked sugar Furfural “sweet” “caramel-like” 5-methylfurfural “sweet” “caramel-like” (structures from Gavin Sacks, Cornell University)

Let’s Look at Some Products Oak Phenolics and Oak Aroma Compounds in 4 Products

Importance of a compound to the odor of a sample OAV = concentration / detection threshold ← Value = 17 Detection thresholds from Chatonnet 1995

Thank You

References Chatonnet, P. 1995. Influence des proceeds de tonnellerie et des techniques d’élevage sur la composition et la qualité des vins élevés en fûts de chêne. PhD Thesis. Université de Bordeaux, Bordeaux, FR. He, F., Liang, N., Mu, L., Pan, Q., Wang, J. Reeves, M., and C. Duan. 2012. Anthocyanins and their variation in red wines I; monomeric anthocyanins and their color expression. Molecules. 17: 1571-1601. He, F., Liang, N., Mu, L., Pan, Q., Wang, J. Reeves, M., and C. Duan. 2012. Anthocyanins and their variation in red wines II; anthocyanin derived pigments and their color evolution. Molecules. 17:1483-1519. Kontoudakis, N. 2010. Grape phenolic maturity; Determination methods and consequences on wine phenolic composition. Thesis, Rovira i Virgili University, Tarragona. Loch, R. 2002. Micro-oxygenation: a large winery case study. In ASVO Proceedings of Seminar ‘Use of gases in winemaking’. Allen, M. (ed), pp. 45-53. Australian Society for Viticulture and Oenology. Adelaide. Ribéreau-Gayon, P., Glories, Y., Maujean, A., and D. Dubourdieu. 2006. Handbook of Enology Volume 2; The Chemistry of Wine Stabilization and Treatments. John Wiley & Sons Ltd, Chichester, United Kingdom. Waterhouse, A. 2002. Wine Phenolics. Ann. N.Y. Acad. Sci. 957: 21-36.

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