Agriculture Reference
In-Depth Information
tage for those vineyards and regions that have established reputations for the dis-
tinctive character of their wines, based on long experience. This may explain why
wine quality in the EU is defined in terms of the region of the wine's origin (see
box 1.1). By this definition,
terroir
and wine quality become inextricably associated.
An Alternative to Terroir
There are several interpretations of wine quality and whether quality connotes
ter-
roir
(Penn 2001). Many in the New World believe wine quality is determined by
selected fruit properties and wine-making skills, and they largely ignore the in-
fluence of
terroir
(soil and climate) on wine character. Instead, the focus is on
measuring those grape properties that appear to correlate directly with wine sen-
sory properties. The concentration of anthocyanin pigments and total glycosol-
glucose compounds in grapes is believed to indicate the intensity of wine flavors
(Gishen et al. 2001). To be used as a quality criterion, these properties must be
measured rapidly at the point of delivery to the winery. To this end, in Australia's
Riverland and Sunraysia regions, BRL Hardy has used anthocyanin concentra-
tions in red grapes, measured by Near Infrared Spectroscopy (NIRS), to assess
grape quality and to determine payments to growers (Kennedy 2001). When used
in this way, NIRS is essentially a “black box” method that must be calibrated
against laboratory measurements of anthocyanin concentrations, as well as pH and
°Brix, using very large sample sizes. The major problem is how to relate the NIRS
results back to vineyard management, so that growers know which practices will
produce the quality of grapes sought by the winery.
9.2.3
Examples of the Expression of Terroir
The objective approach to wine quality discussed in section 9.2.3 is a tacit ad-
mission that generic relationships between soil and wine character are unlikely to
apply widely across regions, let alone across countries in different hemispheres.
For this reason, to investigate more closely whether the soil factor of individual
terroirs
is important in determining the distinctive character of a wine, we must
examine the evidence from specific regions in different parts of the world.
9.2.4
The Bordeaux Region
9.3
Location, Climate, and Geology
There are more than 100,000 ha of vines in the Bordelais, the region surround-
ing the city of Bordeaux and located on either side of the Gironde estuary along
the lower reaches of the Garonne and Dordogne Rivers (fig. 9.1). To the east of
the Dordogne is the St. Emilion-Pomerol region, between the rivers is Entre-deux-
Mers, and to the west of the Garonne lie the districts of Médoc, Graves, and
Sauternes. The land is relatively flat, ranging in elevation from sea level to about
120 m, and the climate is tempered, especially in the Médoc, by proximity to the
sea. The mean annual rainfall in the city of Bordeaux is 920 mm, but the range
from year to year can be large (e.g., 1160 mm in 1960 to 450 mm in 1989). Be-
cause the AOC vineyards are not irrigated, this variability in rainfall means that,
9.3.1
