"Who is buying this stuff?” I always wonder when I pass by one of the wine aisles at a certain 24-hour supermarket in California’s Silicon Valley. Past aisles of everyday wine and not far from a display of pet flea and tick collars and a table of diapers, is a display cabinet of bottles of fine wine, some of it under locked glass. You have to wonder: Do the Mark Zuckerbergs and Larry Pages of the world really need to make 4 a.m. runs for Heitz Cabernet?

Apparently so, or else the supermarket wouldn’t stock it — or at least stock so much of it. What it also reminds us is that a great deal of the world’s wine is purchased at supermarkets and, contrary to common conception, many of these stores sell more than supermarket wine.

Below, I address this myth and others surrounding the purchase of wine in supermarkets:

Myth 1: Supermarkets Have Only Simple, Boring Wine

As my example above shows, this is not always the case. States that allow wine sales in supermarkets increasingly have stores with healthy wine programs. The overall selection isn’t usually as interesting as that of a top wine merchant, but many are perfectly respectable.

Some of the best values in supermarkets and for wine in general reside with the grapes and regions that are just outside consumers comfort zones. So critical is this point that I focused my most recent book entirely on this idea that value and adventure lie in the less familiar. Instead of gravitating to the Chardonnay or Merlot aisles, which will often be dauntingly large — experiment with the store’s more manageable stocks of better-priced Prosecco, Gruner Veltliner or Zinfandel.

Speaking of value, most people don’t realize that wine prices can vary widely among supermarkets. If you are going to realize the full value of shopping at a high-volume store, make sure to comparison shop. It has never been easier with the Internet.

Myth 4: Only Chain Supermarkets Are Fertile Hunting Grounds

There's gold in those hills beyond traditional chain supermarkets and their bottle-based cousins, beverage superstores and other warehouse clubs, which can all thrill with smart choices and fabulous prices. In fact, I once found a rare bottle of Robert Mondavi Cabernet Reserve languishing in the display case of an airport gift shop, amid cherry-scented potpourri and University of Alcatraz sweatshirts.

While it’s true that you are on your own in many supermarkets, you never know when helpful advice is just a question away. I like asking a clerk, “Is the wine buyer available?” When I did this recently at a Whole Foods in Florida, a woman appeared whose knowledge and suggestions rivaled that of the best wine stores.

Every week, Mark Oldman -- wine expert, acclaimed author and lead judge of the hit series The Winemakers -- shares with readers the basics of wine, while making it fun and practical. In the coming weeks, he'll tell you what to ask at a wine store, at what temperature to serve it and share his must-have wine tools.