Alsace is the largest producer of white wines in France. The Alsatian vineyard stretches from Strasbourg to Mulhouse, over more than 15,000 hectares (37,065 acres) of vines planted on hillsides. A fairly dry microclimate increases the impact of continental sunshine in summer and in autumn, white grapes ripen better than anywhere else in France. Since the 1960s, the region has been a pioneer in organic and biodynamic farming: more than half of the estates are certified organic. The vineyard has four types of AOC appellations and 51 identified terroirs.