What's the difference between a Sauvignon Blanc and a Chardonnay?

Hello there! I'm Dr. Vinifera, but you can call me Vinny. Ask me your toughest wine questions, from the fine points of etiquette to the science of winemaking. And don't worry, I'm no wine snob—you can also ask me those "dumb questions" you're too embarrased to ask your wine geek friends! I hope you find my answers educational, empowering and even amusing. And don't forget to check out my most asked questions and my full archives for all my Q&A classics.
Dear Dr. Vinny,
What is the difference between a Sauvignon Blanc and a Chardonnay?
—Comfort, Johannesburg, South Africa
Dear Comfort,
Sauvignon Blanc and Chardonnay are the names of white wine grapes, and of the wines made from these grapes. In general, the Chardonnay grape makes medium- to full-bodied wines, and I often get notes of apple, fig, melon, pear, pineapple or peach from them. If a Chardonnay wine is made in an oaked style, it can take on spice, honey, butter or hazelnut flavors. A variety of styles are made, and the very best ones are rich and complex and can age well.
Sauvignon Blanc wines tend to be lighter-bodied than Chardonnays, often with a crisper, juicier jolt of acidity. They can also be made in a range of flavors, and may have a touch of fresh-cut grass or fresh herb notes, sometimes veering towards more pungent flavors of gooseberry or jalapeño pepper. Fruit flavors can range from citrus to stone fruit to tropical, and some vintners use oak barrels in making Sauvignon Blanc, which can lend it a smoky or toasty note.
The best way to find out the difference is to start tasting examples! Some folks prefer one to the other, but I appreciate any wine, as long as it’s good.
—Dr. Vinny