Mostly Semillon with about five percent Sauvignon Blanc grown to vines averaging forty years of age planted to chalky clay soils. A maximum yield of 40 hL/ha is imposed by the INAO (National Institute of Appellations of Controlled Origin). The vines often produce yields below this limit because the grapes tend to wither when they are over ripened. The harvest is done entirely by hand with several selective pickings for the collection of only those botrytised grapes which have a high concentration of sugar. The grapes are pressed and the must is put into cement vats where the alcoholic fermentation starts. After the addition of pure alcohol, the wine is aged in vats, completely unoaked, for six months.