Upper Loire is an unofficial name given to the eastern end of the main Loire Valley wine region of France. It groups together the likes of Sancerre, Pouilly-Fume and Menetou-Salon alongside lesser-known appellations such as Orleans, Chateaumeillant, Valencay, Reuilly and Quincy. It covers the area where the Loire slowly changes direction from north to west; everything south of this (Saint-Pourcain, Roanne, Forez) lies within Auvergne. Although unofficial, the name is very useful, as it allows the core Loire Valley wine regions to be grouped into four relatively neat blocks from west to east: Pays Nantais, Anjou-Saumur, Touraine, Upper Loire.
There are distinct differences between the western Loire appellations (those of the Pays Nantais and Anjou) and those in the east, and this is reflected in the wines. The moderate, moist, maritime climate so obvious in the Muscadet vineyards changes noticeably over the 220 miles (355km) between Nantes and Pouilly, where it is decidedly drier and more continental. Although they sit at precisely the same latitude, these two parishes differ considerably in their average rainfall, diurnal temperature variation and sunshine hours. This is tangible from the vineyard right through to the wine, and is perhaps best exemplified by the difference between the light, evasive aromas of Muscadet and the grassy, citric potency of Sancerre. These wines also illustrate a further key difference between the opposing ends of the Loire: the soils.
Limestone is the key soil type in eastern/Upper Loire vineyards – a result of their location at the southern edge of the Paris Basin. A significant geological region of northern France (and southern England), the Paris Basin is a shallow bowl of sedimentary rock of various types and ages, the lightest of which are the prized calcareous soils of the Loire, Chablis and Champagne. The key difference in the terroir of the Upper Loire, however, is the prevalence of flint – the silex after which many Loire wines are named. Flint is particularly common in the vineyards of Sancerre, Pouilly-Fume and Valencay and is widely credited for the particular 'smoky' character of their white wines. In fact, Blanc Fume – the name given to the Sauvignon Blanc variety here – translates as 'smoky white' and came about particularly because of this character (known in French as pierre à fusil – 'gunflint'). Flint is efficient at both accumulating heat and reflecting light, which helps the vines to achieve full ripeness during the growing season – an essential bonus in the cool climate here.
Although wine has been made in this area for many centuries, it was not until the second half of the 20th century that the local white wines began to make a name for themselves. Before the arrival of phylloxera in the 1860s, Gamay and Pinot Noir were the dominant varieties and the area was better known for its red wines. When restoring the vineyards post-phylloxera, however, local growers found that Sauvignon Blanc was more responsive to grafting than the red varieties. So it was for entirely practical reasons that Sauvignon Blanc became the variety of choice in the Upper Loire – a development that has proved both harmonious and profitable.
Some of the appellations classed as 'Upper Loire' lie some distance from the Loire river itself, which can lead to confusion. This has in turn led to other titles being used, including 'Central Vineyards' and 'Berry'. The former is technically quite accurate (this area is indeed very close to France's center, and falls within the Centre administrative region), but it omits the key word 'Loire', and neglects the quintessentially Loire identity of these wines – in particular Sancerre and Pouilly-Fume. The latter is the name of the historical Berry province, whose centre was Bourges, a city 25 miles south-west of Sancerre and Pouilly. It is unlikely that this lack of clarity will have any substantial impact on the wines themselves, although it does cause some problems for those creating maps and databases for the wine industry.