By Harold McGee
In recent times, much has been said and written about the importance in wine-making of terroir: the influence on a wine of the particular place in which the grapes were grown. The French word includes the entire physical environment of the vineyard: the soil, its structure and mineral content; the water held in the soil; the vineyard’s elevation, slope, and orientation; and the microclimate, the regime of temperature, sunlight, humidity, and rainfall. Each of these aspects can vary over small distances, from one vineyard to the next; and each can affect the growth of the vine and the development of its fruit, sometimes in indirect ways. For example, sloping ground and certain kinds of soil encourage water to drain away from the roots, and absorb and release the sun’s heat to the vine in different ways. A south-facing slope can increase the exposure to autumn sunlight by 50% over a planting on level ground, and thus extend the growing season and accumulation of flavor compounds.