By Charles Fredy
It is amazing how many wine professionals I meet who are fascinated by geology. I too love collecting rocks; I’ve gathered them from some of the most exciting wine regions of the world. Initially I did so to teach wait staff and wine enthusiasts about the soils that influence the finished wines. Now I find myself digging deeper and studying how vineyard geology, from bedrock to overlying soils, came to be.
Why this fascination? Because geology creates nuances of flavor that distinguish a wine and the region it comes from. When I taste a wine, I look for the type of minerality it holds — it gives a subtle personality to the wine.
The granite rocks on the slopes of Cote-Rotie in the northern Rhone region of France give grapes there an almost iron flavor, while further south, grapes absorb the minerality of river rock. In the northern area of Chablis, Kimmeridgian limestone and chalk soils produce the best Grand Cru wines; those soils are essentially ancient seabeds and fossilized shells. Many of the vineyards of Germany’s Mosel regions have blue slate soils — except those near Urziger Wurzgarten, named the spice garden of Urzig because volcanic eruptions turned the slate there burnt red, adding a spicy component to the wines.
For me, minerality is a subtle and illusive influence that adds complexity while balancing a wine’s fruit, acid and other flavors. More constant than the fruitiness that comes and goes on the palate, this earthiness becomes the foundation that all the other flavors build on.
Many wine labels mention geology. The “silex” in Dagueneau’s Silex Pouilly-Fume refers to the silica in the soil. Some wineries even take their names from the composition of their terrain. Obsidian Ridge Vineyard is one.
Some of my favorite wine regions express striking examples of minerality. The Chablis of Burgundy tops my list; the area’s oldest soil goes back 180 million years to the Late Jurassic, and includes argilo-calcair, a composition of limestone, clay and fossilized oyster shells. Chateauneuf-du-Pape in the southern Rhone is another; large river stones and galets (pebbles) cover the soil and heavily influence the wines there. Study the world’s great vineyards, and you’ll discover a fascinating story of geology, as well.
Here’s a roadmap.
Brocard, Chablis, 1er Cru, Vaulorent, Burgundy, France, 2010
SOIL: Kimmeridgian — a soft limestone or chalk composed mostly of fossilized seashells
Vietti, Barolo, Castiglione, Piedmont, Italy, 2008
SOIL: calcaire (calcium, magnesium, limestone), clay, marl and sand
Henri Bourgeois, Pouilly-Fum3, En Travertine, Centre, Loire, France, 2010
SOIL: flint — a siliceous stone that reflects and retains heat
Emilio Lustau, Dry Amontillado “Los Arcos” Solera Reserva, Sherry, Jerez, Spain
SOIL: albariza — soft, siliceous sedimentary rock; diatomaceous deposits