Daniel Pambianchi MANAGING & TAMING TANNINS JUNE 1-2, 2012 FINGER LAKES, NY 1
Founder/President of Cadenza Wines Inc. GM of Maleta Winery in Niagara-on-the- Lake, Ontario (Canada) Contributing Author to & Technical Editor of WineMaker magazine since 2000 Author of Techniques in Home Winemaking (Véhicule Press, 2008) & Kit Winemaking (Véhicule Press, 2009) Electrical Engineer 20 years in telecom 2
What are tannins? Sources of tannins Winemaking impacts Types of tannins Astringency vs. bitterness Gustatory interactions Reactions involving tannins Physiological effects 3
Astringent, bitter plant-derived compounds Browning precursors Belong to the class of polyphenols; anthocyanins (color) are part of this class Give body and structure ( mouthfeel ) to wine, and impact color and color stability, and aging potential 4
Involved in many types of reactions, which explain changing taste, structure and color from aging Polymerization & depolymerization Condensation with anthocyanins Condensation with polysaccharides (pectin) and peptides (proteins) Oxidation Physiological (non-gustatory) effects 5
HO O Tannins are molecules Anthocyanins are ions; they absorb light that s what gives them color; ionization and color depend on ph Low ph + ionization, brighter red High ph ionization, more purple SO 2 and water have bleaching effects on anthocyanins 6
Grape skins, seeds and stems Scollary, Geoffrey R. GWRDC Tannin Review. FINAL REPORT TO GRAPE AND WINE RESEARCH & DEVELOPMENT CORPORATION, 26 March 2010. http://www.gwrdc.com.au/webdata/resources/files/tannin_review_final.pdf. Varies with grape cultivars, climate, viticultural & winemaking practices, fermentation kinetics, and type and extent of aging 7
Grape skins, seeds and stems (con t) Much higher (100x) in reds than whites Oak (Quercus) barrels & adjuncts Gallotannins Ellagitannins Exogenous additions 8
SO 2 additions at crush Maceration (pre- and post-ferment cold soak) Fermentation kinetics (e.g. temperature); increasing alcohol favor tannin extraction Punchdowns & pumpovers Macro-aeration and/or delestage Enzymes 9
Oak barrels and adjuncts Seasoning & toasting Wood grain (forest) Surface/Volume ratio Barrel fermentation vs. aging Micro-oxygenation Flash-détente 10
Hydrolyzable HO O Condensed HO O Complex HO O 11
Belong to the family of nonflavonoids; phenolic (gallic & ellagic) acid derivatives Insignificant amounts found in pulp Gallotannins Ellagitannins Vescalagin Quercus (oak) Castalagin Castanea (chestnut) More easily oxidized than condensed tannins 12
Condensed means polymerized Belong to the family of flavonoids; class of flavanols, mainly catechins & epicathechins and their derivatives Also known as procyanidins and proanthocyanins Found in grape skins, seeds, stems and leaves; differentiated by degree of polymerization (DP) and distribution 13
DP Distribution (%) Skin 3 83 4 Seeds 2 17 59 Stems 4 28 21 Leaves 16 14
Cathechins dominate in skins; epicatechins (more bitter) dominate in seeds Molecules have many reaction sites Preponderance to binding with anthocyanins and proteins Implicated in astringency, browning, turbidity, and aging process 15
Large polymers of proanthocyanins and gallic acid-derived tannins Also known as flavano-gallotannins and flavano-ellagitannins Recently been isolated in oak bark 16
Astringency a sensation Impression of dryness and roughness; caused by interactions with salivary proline-rich proteins Think of cold tea Bitterness a taste Think of a peel of bitter orange 17
Relationship between tannin chemistry and astringency and bitterness is very complex; much research now elucidating relationship Current theory Astringency increases and bitterness decreases as the degree of polymerization (DP) of tannins increases; DP increases with aging Impacted by anthocyanins 18
Sweetness imbalance Acidity Tannin imbalance Peynaud, Émile. THE TASTE OF WINE: The Art and Science of Wine Appreciation. Schuster, Michael, tr. London: Macdonald & Co. (Publishers) Ltd. 1987. 19
Tannin Alcohol Acidity imbalance imbalance Peynaud, Émile. THE TASTE OF WINE: The Art and Science of Wine Appreciation. Schuster, Michael, tr. London: Macdonald & Co. (Publishers) Ltd. 1987. 20
Tannin Oxygen Hastens polymerization and condensation with anthocyanins Improves color and stability Reduces astringency 21
Tannin Polysaccharides/Peptides Forms colorless to yellow-orange complexes Polymerizes with mannoproteins in secondary lees Reduces astringency (same interaction as with salivary proteins) 22
Tannin Polymerization Forms dark yellow-orange complexes Reduces astringency Exacerbated under oxidative conditions; causes precipitation of large complexes 23
Tannin Anthocyanin Anthocyanins act as bookends; stop tannin polymerization and stabilize color since anthocyanins no longer available to react Reaction depends on relative proportions, or T:A T:A hi high tannin polymerization and increased astringency T:A lo improved color stability and reduced astringency 24
Tannin Aldehyde Anthocyanin Aldehydes: Product of ethanol oxidation Small by-product of fermentation Abundant in toasted oak; phenolic, furanic and non-cyclic aldehydes Aldehydes crosslink tannins and anthocyanins Basis of micro-oxygenation 25
Improves color and stability Most effective in conjunction with toasted oak barrels or adjuncts http://micro-ox.com 26
Dark Red Ruby Red Cherry Red Scarlet Brick Red Light Brick Red INCREASING TANNIN POLYMERIZATION INCREASING TANNIN ANTHOCYANIN CONDENSATION INCREASING OXIDATION INCREASING ASTRINGENCY DECREASING BITTERNESS 27
Aging excessively tannic wines can take years to soften Extended aging on secondary lees; can add glucanase enzymes to increase release of mannoproteins Fining with proteinaceous agents (e.g. egg whites), PVPP or gelatin Adding gum arabic to reduce astringency; adds body and reduces perception of acidity Filter prior to bottling 28
General class of polyphenols currently believed to provide several health benefits with moderate consumption: Antioxidants fighting free radicals Reduce harmful LDL cholesterol oxidation Reduce platelet aggregation 29
Tannins are believed to cause the body to release serotonin a neurotransmitter found mainly in the gastrointestinal tract but also in the central nervous system Serotonin dilates and constricts blood vessels in the brain, which can cause headaches and possibly migraines Serotonin also causes the gut to move faster, which can cause diarrhea 30
http://techniquesinhomewinemaking.com http://techniquesinhomewinemaking.com/blog 31
Pambianchi, Daniel. TECHNIQUES IN HOME WINEMAKING: The Comprehensive Guide to Making Château-Style Wines. Newly- Revised & Expanded Edition. Montréal: Véhicule Press. 2008. 32