"Colorado," Michael Mondavi was saying over lunch a couple of years ago, "is one of our very best wine markets."

Conversation stopped for what seemed like an eternity while I searched my lap to find my jaw. Colorado a major wine market? Not the Colorado I knew in the 1950s and early 1960s. Mountain burgundy then was grape juice and grain alcohol and the local cowboys concentrated on Red Man not red wine.

But Mondavi insisted, and how could I doubt his statistics and sincerity. Still . . . .

Now, two years and two Colorado trips later I must admit the times they are achanging'.

With little more than casual effort and blind luck I found excellent wine shops, a number of them with prices and personnel to please a picky Washingtonian used to some of the best; well-chosen and fairly-priced wine lists in restaurants (something picky Washingtonians are not so used to); wine clubs; a nationally distributed wine newsletter; even a Colorado winery.

Small wonder then that Colorado wine sales increased 35 percent last year, with each Coloradoan drinking three-quarters of a gallon more than he did the year before.

Much of this growth has come through restaurant sales. Gary Topper, national representative for such California wineries as Chateau Montelena, Parducci, Chateau St. Jean and Sutter Home, says "restaurants are now the major point of our Colorado sales." Joseph Phelps' Bruce Neyer agrees: "Our initial thrust was in big discount stores but now over half our wine goes into wine-oriented restaurants. It's been a tremendous success."

I'd have to concur. For evidence I offer the first Denver restaurant we visited this summer, The Apple Tree Shanty, chosen for the simple reason that it was two blocks from our motel. It has one of the finest, most reasonably priced collections of American wine I've seen: 40 cabernet sauvignons, running the gamut from a 1976 Konocti at $6.50 to a 1935 Simi at $125, with most of the stops in between priced from $8 to $20; such fine 1974 chardonnays as Sterling ( $11) and Spring Mountain ( $14), and a comparable selection of zinfandels, chenin blancs, johannesberg rieslings and others.

Their attitude about wine is as impressive as their list. When I could find no half bottles of anything to accompany my rainbow trout, Manager Ray Sanford thought a minute then said, yes, there is something in the cellar worth a try. Indeed it was. A tasty 1970 Wente Pinot Blanc. And at only $2.75.

Up-to-date Denverites tell me the Shanty is only the tip of the iceberg. Sanford says a group of restauranteurs (who call themselves "The Grape Nuts," by the way) frequently gathers to taste and evaluate wines. "We want new members," he said, "so they can also try and buy the good wines available. That way even more customers will benefit."

But you might expect good wine lists in Denver restaurants. The true measure of growth is finding them in more remote places, like Salida (a fine 1977 Macon Lugny, Les Charmes, at the Salida Inn, $8.50), Durango (at the Strater Hotel $9 for Firestone's 1976 chardonnay) and Manitou Springs (a very pleasant 1973 Sichel Bernkasteler Badstube at the Craftwood Inn for $6.50).

There is still an ocean of Lancers, Mouton Cadet and Blue Nun around but variety and selection are definitely "in."

Nowhere is this more evident than at the ski resorts. "This is where the seasoned travelers come," explained wineman Topper, "and they're interested in drinking the best wines."

The surprise to me was that prices in such popular areas as Vail and Aspen are not as high as the surrounding mountains. Two Aspen stores, for example, The Grape and Grain and The Grog Shop, had quite reasonable prices, at least by today's standards: $8 to $13 for 1975 classified bordeaux and $6 to $10 for well-regarded California chardonnay and cabernet sauvignon.

Denver, in addition to that vinous landmark, Harry Hoffman's, has a host of fine new wine stores ("The race is on," one retailer told me), a trend that echoes up and down the front slope of the Rockies. But again it's the emergence of quality shops in out-of-the-way spots like Durango, where there are at least two, that best indicates what's happening.

Even Boulder, seat of the University of Colorado, in my day drier than the writings of some of its college professors, has sprouted excellent restaurants with admirable lists (at Fred's, on the striking new mall, we paid less than Washington retail for a 1973 Simi cabernet) and a memorable retail store, The Liquor Mart. Had it been operating in the '50s I might still be an undergraduate.

To keep all interested consumers abreast of the wine scene, especially locally, two Coloradoans, Bob Slatowicz and Jerry Boyd, founded "The Rocky Mountain Wine Guide" two years ago. An eight-page, bimonthly publication, it has found its way to over 400 subscribers, about half of them in Colorado.

"It's only the beginning," says Slaktowicz, now sole editor of the letter. "We are combining our mailing list with those from other consumer-oriented wine groups and we'll shortly be sending out "Colorado Wine Events," a compendium of everything in our area that's happening with wine -- courses, tastings, events, the works."

No doubt future issues will contain more about budding Colorado wine producers. "There is already a winery in west Denver," Slaktowicz reports, "making wine from hybrids and vinifera, and a lot of people are planting vines. Some of the hybrid wine is not bad at all."

It may not start The Great Wine Rush of '79 but it's reassuring to know that there's lots of wine in them thar hills.