Evaluation of Carcavelos fortified wine aged in portuguese (Quercus pyrenaica) and french (Quercus robur) oak at medium and high toast

• Author(s): McCallum, Michael James
• Date: 2017
• Persistent ID: http://hdl.handle.net/10400.5/15837
• Origin: Repositório da UTL
• Subject(s): fortified wine; Carcavelos D.O.P.; oak wood; aging; toasting
• Document Type: Master thesis
• Language: English
• Advisor(s): Silva, Jorge Manuel Ricardo
• Contributor(s): Repositório da Universidade de Lisboa

Description

Mestrado Vinifera Euromaster - Instituto Superior de Agronomia - UL

Adega do Casal Manteiga is a publicly owned winery by the Municipality of Oeiras that produces Carcavelos fortified wine. The effects of botanical species (Quercus pyrenaica, and Quercus robur) and toasting method (medium and high) on a single vintage wine that has been aged for 8 years is examined. A total of twenty barrels were used with 5 replicates for each factor. The barrels were fabricated and toasted using the same cooperage, J.M. Gonçalves in Portugal. Significant differences were seen between the species Q. robur and Q. pyrenaica were shown impact on total phenolic content including both flavonoids and non-flavonoids. The total phenols of the wine aged in Q. pyrenaica barrels were significantly higher than in the Q. robur counterparts with differences of 61.3 mg/L eq. gallic acid and 75.1 mg/L eq. gallic acid for medium and high toast, respectively. Q. pyrenaica contained more flavonoids than Q. robur with a difference of 35.9 mg/L eq. gallic acid at high toast and 34.2 mg/L eq. gallic acid at medium toast. Regarding non-flavonoid compounds Q. pyrenaica showed 39.2 mg/L gallic acid equivalents more than Q. robur at high toast and 27.1 mg/L gallic acid equivalents more at medium toast. This difference in non-flavonoids was only statistically significant with the high toast barrels. The degree of toasting had significant effects on the Flavonoid content of the wine, as well as the tanning power. Flavonoid content increased for both Q. pyrenaica (Δ37.2 mg/L eq. gallic acid) and Q. robur (Δ35.5 mg/L eq. gallic acid) in the wines that were aged in barrels that underwent higher toasting compared to medium toasting. The tannin power decreased for both Q. pyrenaica (Δ13.66 NTU/mL) and Q. robur (Δ22.78 NTU/mL) when the toasting increased