Abstract
Different microoxygenation procedures before and after malolactic fermentation were applied to Pinot noir wines from two consecutive vintages using the same Pinot noir block and a standardized winemaking protocol. The effects of microoxygenation treatments were investigated by spectrophotometry, HPLC-DAD, and descriptive sensory analysis. Microoxygenation before malolactic fermentation was carried out in 250-L red wine fermentors at oxygen dosages of 20 and 100 mg/L/month for 20 days. Oxygen dosages of 1 and 5 mg/L/month were applied for three months after malolactic fermentation using 100-L stainless-steel tanks. CIELab results showed that microoxygenation in 2006 tended to yield light-colored wines with an increase in yellow tonality. Examining monomeric polyphenols after alcoholic fermentation, this oxygen-induced color loss may be related to the high flavan-3-ol to anthocyanin ratio in this vintage. Furthermore, twice the increase in acetaldehyde content upon microoxygenation after malolactic fermentation was observed in 2006, which indicated excess oxygen for these wines. By contrast, a low flavan-3-ol to anthocyanin ratio was determined after alcoholic fermentation in wines of vintage 2007. Predominantly, these wines showed an increase in blueness upon microoxygenation treatments. Low correlations among astringency related attributes proved that the chosen attributes independently characterized the sensory variation in tannic structure among the microoxygenated Pinot noir wines. Descriptive analysis revealed that microoxygenation predominantly diminished green tannins in 2006 wines. Dry tannins, although decreasing in course of microoxygenation with low oxygen doses, rose again at higher oxygen doses. Beneficial aroma changes in 2006 and the increase of color intensity in 2007 were more salient upon microoxygenation prior to malolactic fermentation. An unfavorable impact on Pinot noir aroma occurred primarily due to microoxygenation after malolactic fermentation.
- Copyright © 2010 by the American Society for Enology and Viticulture
Sign in for ASEV members
ASEV Members, please sign in at ASEV to access the journal online.
Sign in for Institutional and Non-member Subscribers
Log in using your username and password
Pay Per Article - You may access this article (from the computer you are currently using) for 2 day for US$10.00
Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.