Slate. It covered the ground, in many vineyards inches thick, and in others, only thoroughly covered the ground exposing just a few patches of the compact soil beneath.

Since the river twists and turns almost backward on itself, the vineyards all face different directions, north, south, east, west.  It has been said that the south facing vineyards get the most sunlight and the fruit ripens the best here.  The other vineyards will more heavily depend on the Mosel reflection and the warm slate to ripen.

In addition, the slate coverage also prevents water from slipping between the cracks and reaching the soil, so as much as it rains there, the soil can stay relatively dry.  This also forces the vines to dig through the slate soil, tapping into all the minerality the soil has to offer.  The vines’ roots wind themselves around the rocky subsoil, literally curling wrapping themselves around the slate rocks buried beneath the surface when the rocks get in the pathway of growth.

So, different slate, like different types of soil, must contribute different flavor profiles to the wines right?

The book, The Terroir of the Mosel, Saar, and Ruwer Wine Region has possibly some of the best information about the soils of the Mosel, because it is damn hard to find it on the internet, further solidifying my belief and claim that this is one of the most misunderstood regions for winegrowing.

Dark Slate soils typically have a higher density of stone and are free of lime in their clay-loam soils, and therefore does not have the ability to store water over a long term.  Think about it like this: dark clothes attract heat right? The dark slate soils do the same, absorb and store heat efficiently and having a rocky slate cover will prevent rainwater from reaching the soil, preventing erosion, which can happen all too easily on the steep slopes.  The dark slate soils tend to have a richer body and fruity flavors.

Grey-blue slate typically have a reserved and refined aroma, presenting a structured and noble wine, but with no lack of finesse.

Devonian slate exemplifies Riesling with the classic aromas but are further recognized with some greenish yellow tones (mango, passion fruit) but also non fruit characteristics such as herbal, floral, and spiced aromas. Smoky characteristics and of course rocky minerality are also not uncommon in Riesling from Devonian slate.  These wines are complex and have incredible aging potential.  Wehlener Sonnenuhr, Graacher Domprobst and Graacher Himmelreich are all from blue Devonian slate.

Red Slate, a softer slate contains much more loam than the dark slates, and have far less rocky density.  Its ability to hold water is better for older vines. Red slate soil are also slightly less nutritious and vine roots have a much easier time finding the water supply as the soils are soft and easy to navigate without the dense rocky substance. With it’s dark color, red slate soils are also able to attract heat well.  The iron-infused slate leads to distinct aromas and minerality but also yellow fruit like peaches and exotic fruits like pineapple.  The Ürziger Würzgarten vineyard is a famous example of red slate.

These soils  change from one vineyard to the next and general trends reveal themselves as one travels from north to south too, with the landscape.  But we’ll save that for next time.