ALLUVIAL SOIL Fertile soil that has been transported down a slope, by a river or stream. At the bottom of the slope, alluvial soil usually forms a fan that contains gravel, sand, and silt. Alluvial soils are found, in the Napa Valley, near the area of western Oakville at the foot of the Mayacamas Mountains. Chateauneuf du Pape in the Rhone Valley
BASALT Cooled lava from volcanic rock that is high in calcium, iron, and magnesium. Evident in the Willamette Valley of Oregon.
CHALK Very porous, soft limestone soil that vine roots can easily penetrate. A classic soil in Champagne, France.
CLAY Sedimentary rock-based soil that has good water retention ability but poor drainage.
The soil is often very “cool” and high in acid-ity. The Right Bank of Bordeaux is dominated by clay-based soils.
FLINT Siliceous stone (sedimentary rocks that contain silica from silica-secreting organisms such as diatoms and some types of sea sponges) that reflects sun and heat well. The Pouilly-Fumé wines of the Loire Valley are generally produced from flint-based soils.
GRANITE A hard, mineral-rich soil that is composed of 40 percent to 60 percent quartz. The soil warms quickly and retains heat well. Thus, granite soils are ideal with acidic grapes like gamay. Granite is found in Beaujolais, as well as in the Cornas region of the northern Rhône Valley.
GRAVEL Soil that is loose and pebbly and has good drainage and poor fertility. Vines planted in this type of soil must penetrate deeply to find nutrients in the subsoil. The Graves and Sauternes regions of Bordeaux consist predominantly of gravel-based soil.
GREYWACKE Sedimentary soil formed by rivers depositing quartz, mudstone, and feld-spar. It is found in vineyards of Germany, New Zealand, and South Africa.
GALESTRO Schist-based soil found in the Tuscany region of Italy.
LIMESTONE A wide range of sedimentary-based soils consisting of calcium carbonates, many of which are formed from the skeletal fragments of marine organisms. Limestone is consistently alkaline and is generally planted with grapes of high acidity levels. This is a main SOil type in Burgundy, Champagne, and several parts of the Loire Valley. Because limestone is a remnant of some ancient seabeds, certain islands (including the Florida Keys) are made from limestone.
LLICORELLA A soil type found in the Priorat appellation of Spain. The soil is a mix of slate and quartz that is very porous and drains well.
LOESS very fine, silt-based soil composed of wind-borne sediment that is typically angular and decalcified. The soil has good water retention and warming properties. Loess is a common soil type in top Austrian and Washington State vinevards.
MARL Calcareous clay-based soil that is “cool” and thus delays ripening, resulting in wines with prominent acidity. Marl is typically deep and lacking in stone fragments; it is the main soil type in the Piedmont wine region of Italy.
QUARTZ A common material found in sand-and silt-based soils. The high soil pH of quartz can reduce the acidity of the resulting wines. But quartz also stores heat, so it can increase ripening of the grapes. Quartz is very notable in the vineyards of the lower Nahe in Germany, where the wines have stone-fruit and wet stone flavors.
SAND Warm, airy soil that is composed of tiny particles of weathered rocks. One of the few soils that the insect phylloxera does not thrive in (see page 30). The soil drains well but does not have good water retention. Sand is a main component in the soils of California’s south central coast near Santa Barbara. Sandstone is a sedimentary soil composed of sand particles that has been pressure-bound by various iron-based minerals.
SCHIST Laminated, crystalline rock-based soil that retains heat well and is rich in magnesium and potassium, but is poor in organic nutrients and nitrogen. The upper slopes of Alsace’s Andlau region are planted on schist-based soils.
SHALE Fine-grain sedimentary-based soil that can turn into slate when under geologic pressure. The soil is moderately fertile and retains heat well. New York State’s Finger Lakes region boasts shale-rich soil, brought by glacial deposits hundreds of thousands of years ago.
SILEX A flint-and sand-based soil type, found primarily in the Loire Valley, that is formed from a mixture of clay, limestone, and silica.
SILT Soil type consisting of fine-grain deposits that offer good water retention but poor drainage. It is more fertile than sand.
SLATE The most common soil type of the Mosel region of Germany. Slate is a metamorphic, platelike rock formed when shale, clay, or siltstone is subjected to pressure deep within the earth. The soil retains heat well and warms up relatively quickly.
TERRA ROSSA A sedimentary soil, known as “red earth,” that is formed after carbonates have been leached out of limestone. The breakdown leaves behind iron deposits that oxidize and turn the soil a rustic red color. This soil type is found in some areas along the Mediterranean and in Coonawarra, Australia.
TUFA A highly friable calcareous soil created from exploding volcanic rock flung into the air.
Common in the Loire Valley of France.
Taken from The Wine Bible by Karen McNeill & Photo Is Vinepair