THE SOIL
The Sherry Region of Jerez is an area of open, gentle rolling hills or slightly sloping knolls - with gradients of between 10 and 15 per cent - covered by a limestone soil known as albariza, characterised by the extreme, dazzling whiteness it takes on during the dry months. This soft loam of chalk and clay comes to the surface on the tops of the hills, thus giving rise to the characteristic Sherry vineyard landscapes. It is rich in calcium carbonate (containing up to forty percent), clay and silica from the diatomite and radiolite shells present in the sea that once covered the region far back in the Oligocenic period. The finest albariza soil, with the highest proportion of limestone and elements of silica produces the most select and sought after sherry wines in the Marco de Jerez
Its main characteristic from a wine-growing point of view is its high moisture retaining power, storing each winter's rainfall in order to nourish the vines during the dry months. Its leafy structure opens up like a sponge during the rainy season and absorbs immense quantities of water. Later the upper levels of soil bake hard under the heat of the summer, thus preventing the evapotranspiration produced by the region's high levels of sunlight.
Albariza soil is easy to work and, being very moisture retentive, facilitates an excellent distribution of the root system. Roots up to twelve metres in length have been found at depths of up to six metres in albariza soil.