Bordeaux is a seaport city of just over 1 Million people located on the Gironne River in Southwestern France. This is one of the most important wine regions in the world. The region is naturally divided by the Gironde River into a left and right bank. The left bank area includes the Medoc (May-dawk) and the subregions of St-Estephe, Pauillac, St-Julien, and Margaux (Mar-go). The right bank area includes the subregions of Saint-Emillion. Pomerol, Bourg and Blaye. Additional wine regions are Graves which is south east of the Medoc and the subregions of Pessac-Leognan, Sauternes and Barsac. (Click here for interactive map.)
Although nearly all the wine produced in this region is entitled to use the name “Bordeaux”, bottles labeled as such and only such are catch all typically bulk wines. “Bordeaux Superior” is a little better it has a higher alcohol level and the yield per acre is lower.
The best wines come from estates in Bordeaux which are classified according to the reputed quality of the producer.
The left bank of Bordeaux was officially classified in 1855. This classification included most of the left bank estates as well as Sauterne and Château Haut-Brion of Graves.
The estates that were not classified in that listing may be classified under the the Cru Bourgeois label.
Generally the wines produced on the left bank are predominately Cabernet Sauvignon based. The wines on the right bank are more Merlot based.
These better districts produce wines of a different character and class. Great vintages of these wines have been known to hold up and even improve for 50, 60 and even 80 years!
The Graves area produces both red and white wines; the white wines from Sauvignon Blanc and Semillon grapes.The Sauternes and Barsac are more known for the botrytized* dessert wines.
*Botrytis (bo-treat-iss) also known as the noble mold, which in certain districts (notably in the Rhine Valley of Germany and the Sauterne Country of France) forms on the skins of the ripening grapes. This mold causes a concentration of sugar and flavor which makes for a most sumptuous high quality desert wine.
Winetrivia -Fun with Food and Wine 