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50 WINES&VINES February 2016 BARRELS PRACTICAL WINERY & VINEYARD that the ellagitannin concentra- tion in wine tends to decrease with the toasting temperature, as thermolytic degradation occurs during the toasting process and are converted into less astringent products. 13 This could explain the absence of significant differences in terms of tannin perception at the end of élevage in our study. Olfactory perception: Be- yond its impact on wine structure, wood sorting according to tannin potential seemed to have a signifi- cant influence on wine aromas. (See "Wood Aromatic Compounds in Chardonnay," above, and "Wood Aromatic Compounds in Merlot" on page 51.) For the Chardonnay, LTP mo- dality was considered signifi- cantly more fruity than HTP. That same LTP modality presented more intense fresh wood notes and conversely less toasted notes com- pared to the HTP modality. For Merlot, three criteria were impacted: fruity, spicy and vanilla notes. Fruity and spicy notes de- creased along with TP, while the MTP modality exhibited the higher intensity for vanilla notes. For both trials, chemical analy- sis provided a molecular interpreta- tion of these sensory differences. According to recent research, 5 levels of furanic compounds in wines associated with toasted notes increases along with wood tannin potential. For whisky lac- tones, aging under a lower TP resulted in a richer wine. Differences in fruity perception between the different TP classes could also be explained by their respective chemical compositions. A greater concentration of furanic aldehydes and guaiacol reduces wine fruitiness, 14 while whisky lactones can enhance it. 15,16,17 Thus, the tannin level of wood seems to be a determining factor for the levels of extractible com- pounds. HTP barrels conferred the greatest concentration of com- pounds responsible for toasted notes. Given their lower whisky lactone concentration, this sug- www.scottlab.com • info@scottlab.com High-tech meets handcrafted. High-tech meets High-tech meets handcrafted. handcrafted. SIGMA press with patented pressing principle and FLEXIDRAIN® technology for vertical juice extraction. Visit our website for a video of the SIGMA in action. Made In California sales @ giftboxcompany.com www.giftboxcompanyusa.com (562) 926 - 6888 HARD COVER WINE GIFT BOX The Gift Box Company Attention Detail WOOD AROMATIC COMPOUNDS IN CHARDONNAY µg/L 300 250 200 150 100 50 0 Furanic aldehydes (/10) cis-WLactone Vanillin Guaiacol Eugenol High-tannin staves (HTP) will darken more than low-tannin staves when sub- jected to the same toast. Many coopers use a visual clue to decide when to stop toasting barrels, but much of the color is due to tannin rather than toasting. n Low tannin potential n High tannin potential