Loire Valley (wine) a variety of limestone with excellent drainage that is known as tuffeau which is the same material used to build many of the famous Loire Valley Châteaux. The area around Chinon, Bourgueil and Saint-Nicolas-de-Bourgueil produces the majority of the Loire Valley's red wine based on the Cabernet franc grape—known in this areas as "Breton". The wines of the Chinon area are the softest and rich expression of the grape while the Bourgueil area produces more tannic and firm wines. The St-Nicolas-de-Bourgueil area produces the lightest colored wines. In the 19th century, the wines of the Chinon area were compared favorably
Loire Channel to its new outfall into the Atlantic Ocean thereby creating the presently seen narrow terrain of gorges, the Loire Valley with alluvium formations and the long stretch of beaches along the Atlantic Ocean. The river can be divided into three main zones; the Upper Loire which is the area from the source to the confluence with the Allier, the middle Loire Valley which is the area from the Allier to the confluence with the Maine, about , and the Lower Loire which is the area from Maine to the estuary. In the upper basin the river flows through a