The physical aspects of Sangiovese terroir: Chianti Classico DOCG

As noted previously, “Sangiovese is an impressionable grape variety that easily takes on characters from the specific soil or terroir ...” a fact which has led me to elaborate the physical aspects (climate, soils, aspect, elevation, etc.) of the various Sangiovese terroirs. To date I have explored the physical environments of Brunello di Montalcino DOCG, Vino Nobile di Montepulciano DOCG, Morellino di Scansano DOCG, and Montecucco DOC(G). In this post I will be covering Chianti Classico DOCG.

The modern Chianti Classico production zone encompasses a series of hills -- elevation between 200 and 600 meters -- that are bordered by Siena to the south, the Florentine town of San Casciano Val di Pesa to the north, the hills of the Arno River Valley to the east, and the Elsa River Valley to the west. Originally referred to as Chianti, the area shaded in blue in the map below was recognized as a wine region since the 13th century but was legalized as such by a decree issued by Grand Duke Cosimi III de Medici in 1714. A Ministerial Decree issued in 1932 expanded the Chianti region to cover eight sub-zones, one of which was the original Chianti. The former Chianti was expanded to its current borders (shown in the map below) and given the name Chianti Classico in a bow to its historical origins. Chianti Classico was granted DOCG status in 1996.

Tuscany wine region map (ateliersetsaveurs.com)

Climate

The Chianti Classico climate is continental, with long summers and cold winters. Various aspects of the climate are illustrated in the chart below.

Sources: Map - pinterest.com; information - Nesto and
di Savino, Chianti Classico

As shown on the chart, the combination of the Chianti and Pratomagno Mountains block morning sunlight from the region. In the southeast of the region, the upper Arno River valley opens up to the east and south, allowing in some morning sunlight.

According to Nesto and di Savino, climate change is forcing vineyards to migrate to higher elevations. Thirty years ago, according to the duo, vines planted above 350 m subjected their growers to ridicule; 350 m was considered prime real estate for Sangiovese. Today 500 m is desired. Alcohol levels are increasing such that in the warmer Chianti Classico areas, less sun is preferred, leading to a preference for north and northeast exposures in those zones.

As it relates to seasonal weather hazards, there is potential for bud damage from spring frosts and damaging summer hail resulting from warm humid winds rising from low to high elevations. 

Landscape and Soils

Coltorti, et al., provide insight into the population of rock types encountered in Siena Province (see chart directly below) while Bonini and Sani and Amato and Vallatto, respectively, provide soils distribution in Chianti Classico by percentage and by location.

As shown in the preceding charts, the region possesses a diversity of soils: marl (San Casciano Val di Pesa); calcareous clay (Greve and all zones at lower altitudes); sandstone (backbone of Chianti Mountains); limestone (central and southern portions of the district); and tufa (around Castelnuevo Berardenga). When limestone and sandstone are found in alternating layers, that soil is called Galestro. Clay-limestone mixes are called Albarese. According to Berry Bros & Rudd, "The sandy alluvial soils of the lower sites yield fuller, meatier wines while the limestone and galestro soils of the higher vineyards deliver finer, more ethereal examples" (bbr.com).

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