French and American oak : Latest scientific knowledge Innovative implementations for bulk wines Benoît Verdier Director of oenological development World Bulk Wine Exhibition Amsterdam November 27th of 2018
Program of presentation 1. Keys of differentiation of species and consequences 2. New scientific knowledge to consider 3. Examples of use for bulk wines 4. Tasting: Untoasted oaks Toasted oaks.
American oak Main Area of Supply Assimilation of Q.alba (major specie) with other species (Q. prinus, Q; bicolor, Q.muehlenbergii,, Q. stallata, Q. macrocarpa, Q. lyrata, Q. duranta etc ) under generic name: American white Oak
American White oak American Red oak Occurrence of thylosis, Chemical composition is suitable for barrel use Absence of thylosis, Chemical composition is unsuitable for barrel use
American VS French oak 1. Thylosis - generation of thyles, which block wood vessels in hardwood American White Oak French Species (Q.robur/Q.petrea) American Red Oak Significant thylosis Partial thylosis No thylosis 2. Density: American oak denser than French species 0,65 versus 0,55 (note: average values)
American VS French oak French oak only radial cut (25% yield) American oak sawing in radial and tangential directions (55% yield)
American VS French oak Grain key of classification of French Oak, because: Link to species (sessile oak is more tight-grained than pedunculate oak) Correlation between grain and tannin amount (grain wideness tannins )
In contrast, American VS French oak Grain is a useless criterion for classification of American oak, because: No link to species (14 different species with a very high variation of grain tightness) No correlation reported between grain and tannin amount
Q. sessilis Q. pedunculata Q. alba American versus French oak Flavor potential French sessile oak French pedunculate oak American species Whisky-lactone Ellagitannins American Oak is more aromatic and less tannic than French species
1 Keys of differentiation and consequences French oak American oak Comment / Alternatives Species 2 : Q Robur, Q Petrae 14 : Q. Alba, Q. prinus, Q.bicolor, Q.muehlenbergii, Q. stallata, Q. macrocarpa, Q. lyrata, Q. duranta etc Yield on rough staves AO usually more aromatic but not always! Dosage of chips is low 25% 55% Explain cost of barrels but not oak wook pieces. Density 0,55 0,65 Usually not taken in account for oak dosage Impact on toasting process Maturation time 18-36 month 0 36 month Impact on tannins, lactones, and aldehydes. Grain => dominant specie and consequently on oak composition. Not a reliable key of selection Few suppliers use this key of selection for oakwood pieces. Oak volatile compounds Lactones low concentation => 0 to 50µg/g Lactones high concentation => 0 to 200µg/g Key in oak aromatic profile! Oak non-volatile compounds Tanins QTT : Q Robur : 1-3µg/g Q Petrae: 2 200µg/g QTT: 1-3µg/g Indirect impact of tanins! Perception QTT in wine : 590µg/L (10000 less than glucose!)
Oportunities/risk of use of American oak Opportunities: 1. Sensorial complementary tool with French Oak 2. Efficency on oak profile (style, intensity) 3. Cost efficent at low dosage Risks 1. Unconsistent impact (more variability than European species) 2. Dry on palate => trials and consistency of oak suplier process
2. Some recent scientific knowledge to consider C and D compounds = Quercotriterpenosides QTT I et II Marchal, et al. 2011 Perception threshold QTT I = 590 μg/l (10 000 times lower than sugar!)
QTT: American versus French oak Center of France (majority sessile) American oak Limousin (majority pedunculate)
Selection of raw material Analyse of logs and use of lots according to their oenological potential.
OenoFinisher concept : reach balanced profiles in minimum time! Optimize Oak composition Blend Kinetic Durée de macération Expressive Balance Stable Durée de macération
Tight Example of use : Finishing Special oak selection Compacted chips in bricks Tight infusion mesh bags : no impact on filterability Only 1-2 weeks contact time! 4 blends available 1. The Original: Volume, roundness. Reinforce fruity expression and olfactive complexity. 2. Toast Booster: Grilled-smoky, Spicy 3. Vanille Booster: Vanilla, pastry, Ripe fruits notes 4. Spirit Booster : fresh fruits and floral notes for spirits
3 Example of use Durée contact 1-2 semaines Fermentation: Oenofirst 0,5-1 /HL Finishing OenoFinisher 0,3 2 /HL 1-3 mois Aging: CHIPS 0,7-4 /HL 3-6 mois Aging : BLOCKS / STAVES 3 22 /HL Réception grappes Fermentation alcoolique Fermentation malolactique Elevage Expédition
Dégustation Merlot 80%/Cabernet 20% France (Bergerac) 2017 13.5% Vol. 10T/ha Contact time: 1 month First Round : untoasted oak Control 5g/L French oak 5g/L American Oak 5g/L French Oak («Oenochips Exception») Second Round : toasted oak Control Oenochips R02 : 3g/L (FO) Oenofinisher (Original) : 1g/L (Blend) Oenofinisher Vanille Booster : 3g/L (Blend) Oenofinisher Toast Booster : 3g/L (FO)