The wine in this region is wonderfully tasty and mostly white (there is one red grape, the pinot noir). Alsatian wines are "varietal," meaning pressed from one grape variety, and are identified by grape and the maker’s name. There are a few variations on that, but mostly this is how it is done.
The vineyards stretch for over 200km (130 miles) across the foothills of the Vosges Mountains. They start in the south at Thann and extend all the way north to Marlenheim. You can drive this wine route for miles and miles and see nothing but vineyards and quaint little villages with cobbled streets, bright flowers and people enjoying the scenery.
Should you decide to follow the route for a while, make sure you have a map with you. There are signs to follow the route, but we missed our turns more than one time because there just aren't enough signs. We finally decided to follow the general rule at the roundabouts that if there was no sign, go straight. It also takes a great amount of time to wind your way through these villages. We wound our way through for some time and then got on the Autostrada going south from Strasbourg to make up some time.
Alsace is about as far north as you can go when it comes to grapes in France. The area is cast in the rain shadows of the mountains. This creates just enough rain for the vineyards. The best wines in the region are the ones that are located further east, right on the foothills. "The best vineyards in the area lie at a fairly consistent altitude, between 200 and 350 meters (656 and 1146 feet), on fairly steep, well-drained soil, slanting southeast to south, making the most of the available sunshine" (Quoted from Oz Clarke's Wine Atlas)
There are whole books written on grapes and wine and all of the different distinctions. I will give you a few brief ideas about the wines in Alsace:
Most of the finer wines come from the central section of vineyards in the Haut-Rhin department, just to the west of Colmar. Many of the vines that are worked in the Alsace area were planted many centuries ago by Romans.
Grand Cru wines are quite fine. The name was applied to areas of land where the finest grapes were produced. Alsace has around 50 Grand Crus now that represent only 4% of Alsace's wine production. Only four "Noble" grapes in this area are entitled to the status: Gewürztraminer, Riesling, Pinot Gris and Muscat d'Alsace.
The next level down is simply the Alsace AC (meaning Appellation Control). This appears on all labels and any grape variety is acceptable. There is no intermediate level for the wines, but the French system seems to be out-of-whack right now and they are working on creating different levels.
There are a couple of others worth mentioning. There are dessert wines from the region called Vendange Tardive made from late-harvested grapes that are sweeter. Also, you will find Cremant d'Alsace AC, which is the sparkling wine made with the traditional methods of champagne (although only sparkling wines from the Champagne region can use this designation).
If you like wine, this is definitely a great place to visit. The wine is cheap and readily available. There are many places to do wine tastings to decide what to buy. You can also sit at a Winstub and drink to your heart's delight! The quaint little villages and all of the shopping available is just an added bonus to the great wine.