Over the past few years the buzz has centered around everything from Viognier, Roussanne, Pinot Gris, to most recently Muscat. In the meantime some have missed the growth of off-dry Riesling. It's still a drop in the bucket (or would it be barrel?) to Chardonnay in terms of sales, but it's growing fast.
Why? One reason it probably because it can be easy drinking in the off-dry style with a bit of residual sugar. It will still have decent acid making it refreshing. Also, it's rarely over $25 and there are many for half that. In the last few years the biggest growth has been with wines selling for less than $12.
One of Riesling's (and Gewurztraminer's) problems with wine shoppers has been not knowing if you're getting a dry, off-dry, or slightly sweet wine as American labeling laws don't require this though some wineries will let you know. Gewurztraminer's other problem is nobody can pronounce it. Just try saying, "I'll have a Gundlach-Bundschu Gewurztraminer please." (I just say "gah-verts). So for these American-made wines to really catch on in the U.S. they will have to be labeled with something like Dry, Off-dry, Sweet, and Dessert.
Riesling is best known as an import from Germany though at one time it was heavily planted in Napa and Sonoma. In the U.S. you now find it mostly in the Finger Lakes and Niagara regions of NY, in Washington state, and in cool coastal areas of California, mostly Mendocino and Monterey Counties. But there are places as diverse as Michigan and Southern California growing it. I would think the cool coastal regions of Sonoma County would be great for Riesling but these are currently being planted in Pinot Noir plus some Chardonnay and Syrah.
Locally a couple wineries making quality Riesling are Smith-Madrone (just over the "border" into Napa) and Navarro in Anderson Valley (Mendocino County). I've said in the past if more wineries could make Riesling and Gewurztraminer like Navarro then more Americans would drink them.
One thing that may be interesting to watch for if Riesling sales really take off is what happens to Sauvignon Blanc. Sauv Blanc's flavors are somewhat similar to Riesling's, but Sauv Blanc is made pretty much bone dry. That style is too acidic for some people. Will winemakers start making off-dry Sauvignon Blancs?
Actually, Riesling and Sauvignon Blanc are great summer whites. Give one a try and save several bucks over one of those big, flabby Chardonnays.