We all know that wine labels are
important, and that they should provide us with information about the wine. But American wine labels, particularly for consumer table wines, can be awfully confusing. For one thing, in terms of the law, in America as long as at least 75% of the wine comes from the grape variety named on the label, it's considered a varietal wine. A bottle that says Cabernet Sauvignon may well be 25% Shiraz, and 75% Cabernet Sauvignon, or some other blend. For some, this is a horrific disclosure; for my part, I'm fine with it, but I do wish that wineries would be more transparent about what they are putting in the bottle. It's not going to affect how the wine tastes to know, and it is interesting information. Honestly, the wineries that do specify the varietal wines in a blend, even if they don't list the percentages (and I think that's reasonable to want to keep private) are showing some pride in the art of blending.
European wine labeling traditions concentrate more on the geographic area involved in grape production, not only in terms of the official appellations or governmentally approved geographic regions of wine production, but in terms of even more specific identifications of regions, or even a village. In addition, there are European traditions around blended wines, some of which are hundreds of years old, but which are, well, usurped in terms of American wine labels. For instance, Burgundy, and Claret are frequently used on wine labels in America in terms of blend description rather than to the geographic areas the wine came from. These labels in the U.S. are, well, semi-generic.
For instance, a traditional French Bordeaux blend can be red or white. Reds are usually some combination Cabernet Sauvignon, Cabernet Franc, Merlot, Petit Verdot and Malbec. The idea is that the blend is adjusted from year to year to both match the traditional expectations, and to present the best face for the grapes from that vintage. In America, Burgundy is, well, nothing to do with region or much besides an indication that the wine is a blend of red wines. I've written about American Burgundy before; an American Burgundy wine is, unlike French Burgundy wines, not likely to have much Pinot Noir in the blend, and might not have any.
Chablis in France refers to Chardonnay from the northernmost part of Burgundy. Chablis is typically a dry Chardonnay that, because of the cool climate and limestone soil, tend to be known for their mineral quality. There is a complicated Cru system for labeling and identifying French Chablis. In America, Chablis generally means a white wine blend that is typically without a vintage, and might or might not contain Chardonnay. It is no longer legal for new wineries to use the label Chablis; it is restricted, legally, much as Champagne is. Nontheless, you will still find older wineries still using the Chablis label inaccurately "grandfathered" in. It might be more helpful to think of American Chablis as something more akin to the French concept of a white Burgundy blend.

