The chalky areas, known as "Albariza", which make up some 62% of the vineyard, are ideal for the Palomino, the main grape by far for Sherry production. The albariza has great properties as a soil, as it acts like a sponge absorbing the winter rains, and dries on the surface in summer, retaining that water. It can be incredibly muddy and slippery when wet and blindingly bright white when dry. Also it can be quite pure with up to 40% calcium carbonate, the rest being clay and silica from long extinct shellfish. Soils such as these are easy to work for humans, and easy for the vines to extend their root systems. Most of the famous "Pagos" or top vineyards, of which there about 300, are to be found on albariza.
The heavier clay soils, called "Barros", and the sandy coastal soils, called "Arenas" accommodate the less fussy grape, the Moscatel. It is happy on any old soil. The other important grape, the Pedro Ximenez - or PX - is generally found on albariza. Below left is a shot of albariza banked up to catch the maximum winter rain. This is called "aserpiado". In the spring, the soil will be levelled off again. Below right is a shot of the 3 soil types, showing just how white is the albariza.