Whenever you pick up a bottle of French wine and look for some inkling of the grape type yet find nothing but snobby French terms like "le" or "Chateaux," don't be too discouraged. Slap yourself on the hand and remind yourself, while the appellation system may be as annoying for most blue or red or white blooded Americans as Velveeta is to a French person about to tip a corn chip in a Tex-Mex Salsa-con-processed-"Queso," they can come in handy too.
When? Oh, good question. With French cheese and wine pairing.
Part 1. I love Sancerre. And Sancerre loves goat cheese.
Sancerre is a French town inside the Loire Valley appellation. It is one of the many appellations within the Loire Valley region. A wine made in Sancerre is always Sauvignon Blanc. Legally. Punishable by death.
Resulting from Appellation d'Origine Contrôlée laws enacted in 1953, French wines are always labeled in reference to the region in which the wine is grown, not the grape. The government mandates what can grow where. Likewise, if a French wine has a grape varietal, like Chardonnay, printed on the label, you’ll know that the winemaker isn’t growing the wine in the region specified by the government. If they were, they wouldn’t need to state the varietals. It would be clear to winos everywhere in Europe. The trick to knowing what type of wine is in that bottle you're holding is knowing what grape varietals the French government allows its wine producers to grow in which appellation. In Sancerre, the government specifies that only Sauvignon Blanc should be grown.
You might be thinking this is crazy. It’s certainly interesting. But it's also smart, and will later help us pair French wine with French cheese. It's smart, first of all, because after centuries of growing grapes in France, the French know what grape grows best in what area. Sauvignon Blanc likes sun, but low heat, maritime climates, and mineral-strewn soils. If Sauvignon Blanc is the best white grape to grow in the Sancerre region, in the Loire Valley, where the often naturally limestone-flecked vineyards nurture the mineral flavors in the grape, so grow it. Or grow it legally in the neighboring Loire Valley towns of Touraine or Quincy…..Bordeaux is also an excellent environment for Sauvignon Blanc. And so there it is also grown, with Sémillion, which also thrives in the region. With permission from Appellation d'Origine Contrôlée team housed in Paris.
See http://en.wikipedia.org/wiki/French_wines#The_appellation_system for more info about Appellation d'Origine Contrôlée laws.