Issue link: http://winesandvines.uberflip.com/i/235959
w i n e G R O WIN G (False Bay) during the noted hours. The main effect of this sea breeze was to cool down the berry and canopy temperature without directly affecting stomatal conductance. The treatments did not significantly affect the berry fresh mass and main grape berry maturity parameters at harvest (see Table I). Fifty percent flowering occurred Nov. 20, 2011 (from here on referred to as the date of flowering), véraison (50% of berries softened) was Feb. 2, 2012, and the grapes were harvested on March 13, 2012. The concentration of IBMP was analyzed in whole grape berries, twice before véraison (53 and 59 days after flowering), around véraison (73 days after flowering), during ripening (94 days after flowering) and at harvest (113 days after flowering). For the morning-exposed treatments, only exposed berries were collected for MPs analyses and shaded treatment berries were sampled randomly within the entire canopy. Leaf and lateral shoot removal from the fruit zone on the morning side resulted in lower IBMP concentrations during ripening (Figure 6). Significantly higher concentrations of IBMP were observed in the shaded treatment compared to the morning-exposed treatment for samples at 51, 59 and 73 days after flowering. At 94 days after the date of flowering and at harvest, no significant differences were noticed between the treatments. A rapid decrease in the IBMP concentration in grape berries for the first three sampling dates of the morning-exposed treatment was observed, that could be a result of a lower IBMP synthesis in the grape berry which is most probably a consequence of early leaf and lateral shoot removal (berry pea size phenological stage).17 From 94 days after the date of flowering to 113 days after flowering (harvest), little change was noticed in the IBMP concentration of the morning-exposed treatment. Whereas the concentration of IBMP in the shaded treatment decreased slowly up to harvest for the same time period. The final IBMP concentration in the grape berry at harvest can differ significantly between harvest seasons, being dependent on both leaf removal (direct or indirect effect of light in the fruit zone) and the climate (effect of temperatures: average, maximum and minimum including temperature differences between day and night).10 The interaction between light and temperature in the fruit zone is complex and 30 p r acti c al w i ne ry & v i n e yard JANUARY 20 14 Figure 5: An example of sea breeze and temperature evolution in 24 hours. Figure 5 represents wind speed at the mesoclimatic level (Meso-wind), in the fruit zone in the morning side-exposed treatment (100% EXP interior wind), and in the fruit zone in the shaded treatment (100% SH interior wind). Temperature evolution has been recorded at the mesoclimatic level (meso-T), in the fruit zone for the morning side exposed treatment (100% EXP interior-T) and shaded treatment (100% SH interior-T). Climatic data collected above the canopy were considered as the mesoclimatic data, whereas microclimatic data were collected at the fruit zone. The mesoclimate could be defined as the climate at the vineyard level. the goal of this study was to clearly show the direct effect of light intensity on fruit IBMP concentration and the very complex and indirect relationship between fruit and wine composition and wine sensory description. The direct effect of the vintage that was observed, compared to the effect of temperature, was due to the effect of the heat waves and time and duration of the heat waves during fruit development and ripening. This allowed demonstration of the overlapping effect of temperature irrespective of the light intensity at the fruit level, even in a site (terroir unit) where the sea breeze cooled down the fruit temperature during the hottest hours of a day. IBMP concentrations in produced wines were lower than what was found in the grapes as was expected due to the decrease in IBMP after juice clarification as previously observed.14 No significant difference in the IBMP concentration in grape berries between both treatments was observed at harvest, whereas the IBMP concentrations in the wines were higher in the shaded treatment when compared to the morning side exposed treatment (Figure 7). Slightly higher, but not significantly, IBMP concentrations in grape berries from the shaded treatment could explain higher IBMP concentrations in the wines. Due to the natural heterogeneity within the vineyard that can counteract the effect of the treatments, the larger winemaking sample (at least 50 kg of grapes) may be more representative in comparison to 100 berries used for grape berry analyses. The IBMP concentration in wine from the shaded treatment was above the detection threshold (2 ng/L), corresponding with the attributes detected during sensory wine evaluation. Figure 8 shows the separation in wine sensory perception between the shaded and the morning side exposed treatment, with green attributes mainly linked to the shaded treatment (no leaf removal) and tropical fruity attributes linked to the exposed treatment (morning side exposed bunches). Using principal component analyses (PCA), descriptors such as green pepper, grassy and overall greenness were grouped with IBMP. Tropical descriptors (grapefruit, passion fruit and guava) were mainly grouped with varietal thiols such as 3-sulfanyhexan-1-ol (3SH), 3-sulfanyhexyl acetate (3SHA) and some