Overview of the Mosel Valley
- By Jacky Blisson MW
- 29 Oct 2020
- 5 MIN
- Level 101
The Mosel Valley is one of the oldest and most revered wine regions for fine Riesling wines. It is located in western Germany, near the borders with France and Luxembourg.
The Mosel Valley takes its name from the long, sharply-winding Mosel river. The river starts in France’s Vosges Mountains (where it is called the Moselle) and ends when it intersects with Germany’s mighty Rhine river. Two tributaries of the Mosel, the Saar and the Ruwer, flow across the southern Mosel Valley.
The region’s best vineyards are planted on steep slopes that rise up from the rivers. Located along the 50th parallel, the Mosel Valley is right at the northern reaches of the latitude band where viticulture is traditionally considered possible.
The Mosel Valley consists of six districts but is generally divided into three main growing areas: the Lower, Middle, and Upper Mosel. The Lower Mosel is the most northern section, where the Mosel meets the Rhine. Its soils are largely composed of clayish-slate. The Middle Mosel is considered by many to produce the longest-lived Rieslings on its steep slopes of Devonian slate. Finally, the Upper Mosel, to the south, produces lighter, racier wines on chalky soils along the Saar and Ruwer tributaries.
The Mosel Valley has a distinctly cool continental climate. Although temperatures have been warming in recent years, it is still considered a cool climate growing area with marginal ripening potential. The piercing acidity, ethereal lightness, and taut structure of many Mosel Rieslings is evidence of this climate.
Three major factors allow the Mosel’s best vineyards to ripen their grapes fully to produce complex, characterful wines: the region’s slopes, slate, and rivers.
Just over half of the Mosel’s vineyards are situated on steep, often-terraced slopes ranging from 30 degrees to dizzying 70 degree inclines. Here, vineyard work must be carried out by hand, vines must be individually staked, and soil erosion is a constant concern. Despite these challenges, the steepest sites, notably the south-facing slopes, are the most acclaimed.
This is because the vineyards face the sun at a more direct angle, increasing the intensity of sunlight they receive thus accelerating the rate of photosynthesis and improving ripening. Slopes also accelerate cold air drainage, as cold air is heavier than warm air and will naturally descend to lower lying areas.
Slate is the main soil type on the Mosel Valley’s slope-side vineyards. The notion that soil types can impart flavour to wine is hotly debated by global wine experts. Nevertheless, the wine producers of the Mosel are near unanimous in their feeling that their slate topsoils are responsible for the flinty aromas and tingly texture of top Mosel Rieslings.
Slate is porous and drains very well. This is particularly important in the often-rainy Mosel Valley as wet soils can reduce vine root growth and restrict ripening. Furthermore, slate has the ability to reflect the sun’s rays up into the vines’ foliage and fruit during the day, and continue radiating heat as the temperature cools in the evening. This is a significant factor in increasing ripening.
The proximity of a marginal wine region to a body of water can radically alter its grape growing potential. Water maintains stable temperatures longer than air. It can therefore act as a heat reservoir, warming a region long into the chillier autumn/fall months. The Mosel Valley’s signature grape, Riesling, is a mid-to-late-ripening grape and requires mild fall weather to fully ripen. The Mosel, Saar, and Ruwer rivers are therefore vital aspects of the Mosel landscape. They also reflect sunlight up into the vineyards thereby increasing sun exposure.