Bonjour, Mesdames et Messieurs. Let’s move on to a new chapter of the most mysterious and intricate wine topics: terroir and vintage.
Introduction of “Terroir”
Terroir is a French term which is derived from “Terra” in Latin that means land, and there is no English equivalent for the word. Robinson and Harding (2015) and Winefolly (2013) suggest that terroir includes several factors:
Climate: it is an average observation including rainfall, temperature and weather (it often refers to vintage, see Vintage below) over a long period of time. Climate can be further divided into macro (region), meso (vineyard) and micro (plot) climate which may cause variations on wine characteristics within a region. There are three main types of climates which are suitable for vine growing: continental, maritime and Mediterranean.
Geology: soil is chiefly discussed under this section. Soil types can be catergorised as sedimentary (limestone, sandstone or gravel), igneous (granite or quartz) and metamorphic (gneiss, slate or schist).
Grain size and pH of soil are crucial to viticulture. Grain size is associated with fertility that soil particles contain anions or cations depending on types of soil. Fine grained soil such as clay is very likely to be fertile because it contains anions which attracts cations that are generally nutrients including calcium, magnesium or potassium. The attraction results in rich soil. In contrast, coarse grained soil tends to be poor like stony soil (gravel) as the soil does not contain anions to bind those nutrients.
The relationship between pH of soil and wine pH is contradictory. To specify, alkaline soil often produces wine with lower pH whereas pH is most likely to be higher when wine made from grapes grown on acidic soil.
Hydrology: it often refers to the relation between water and soil. An ideal type of soil should have a certain number of pores for water evaporation, a desired level of drainage for appropriate water stress. Without proper conditions of drainage and water stress, it could promote excessively vegetative growth (leaves, shoots and flowers) instead of reproductive growth (fruitfulness, phenolic ripeness and sugar ripeness).
Topography: topography is one of imperative elements of Terroir, and terrain is a bullseye of the element. There are several natural features including aspect (certain facing in different hemispheres may extend sunshine duration that is favourable for photosynthesis and phenological growth), elevation (it also contributes to lengthened sunshine hours, diurnal range and temperature moderation in some warm regions), proximity to river or lake (it often assists to develop noble rot, temperature regulation and heat reflection), can be found in most wine growing regions which may result in unequalled wine styles among wine regions.
Traditions: it refers to viticultural or oenological practices which are adaptions to unique regional terroir. For example, Portuguese Vinho Verde (green wine) is a light-bodied, low alcohol, slightly fizzy wine with fairly high acidity. The region is located in northwestern Portugal where is near the Atlantic Ocean and influenced by maritime climate, so that it has consequent high rainfall during growing season, and a potential risk of grey rot contamination. In order to tackle the issue, local wineries or grape growers introduce pergola training system, which vines are trained away the ground, is able to promote air circulation and reduce the grey rot infection. In addition, they pick grapes early and stimulate malolactic fermentation as acidity softening process that produces carbon dioxide at the same time.
Vintage is referred to weather as an annual climatic variation. There are certain weather conditions and satisfactory level of rainfall requirements during grape vine growing cycle. An outstanding vintage is that a year which weather and rainfall are ideal for each phenological stage. To give an example, it was a legendary vintage in 2009. Each stage in the growing season was promising. Vines had significantly benefited from ideally warm dry weather from early summer to harvest with a minimum level of rainfall for vine’s survival, all of which resulted in unrivalled long-lived Bordelaise wines which are crowned by wine critics around the world.
The Oxford Companion to Wine 4th Edition, Robinson. J and Harding. J.