(WineSpectator) - America is now wine's biggest market, and younger drinkers are starting to shape it.

Wine is not tea—there are no leaves at the bottom of a glass that can predict the future. But it is possible to look at how wine sales have changed in the past decade and at what America's youngest wine drinkers are buying in an attempt to forecast what's next. Here's what the sediment says.

American wine drinkers will have an outsized influence on the global wine industry in years to come. The United States is the most important market for wine today and in the foreseeable future. After passing the French and Italians for largest total wine consumption in 2011, according to Impact Databank, Americans consumed 324 million cases of wine in 2012. That's a 7.7 percent increase over five years ago. And that number is only expected to grow in the next five years. What's more, 2012 is the first year America was home to 100 million wine drinkers, according to a Wine Market Council (WMC) study. "One hundred million wine drinkers cannot be ignored," said WMC president John Gillespie, at a presentation of the findings in January.

While Baby Boomers and Generation Xers make up the majority of today's wine consumers, the large Millennial generation (ages 21 to 34) will shape wine's future. So what impact are they already having?

One obvious change is the end of a two-color palette, as dry rosé has shifted from a minor player to frequent year-round quaff. Another is the phenomenal growth of sparkling wine, which is no longer being served only on special occasions. The third significant development is that this young generation is buying more imported wine.