HINTON - Snow-dusted grapevines, now dormant, line a south-facing hillside covering just one of Barry and Brenda Dittmer's 155 acres.
This year's harvest is in, and the Dittmers were inside their winery on the crest of the hill one recent afternoon, bottling some of their 2008 vintage wines.
Of course, this isn't Napa Valley - it's Hinton, Iowa. And the Dittmers' winery contains three stainless steel tanks holding more than 500 gallons of wine among them, plus an assortment of smaller steel barrels also filled with wine in various stages of maturation.
''Fermentation takes seven to 10 days, and then it's wine. But it doesn't taste very good,'' Barry Dittmer said. ''Each month, it gets a little better,'' he added as he pumped wine from a small tank and fed it through food-grade tubing into a bottling machine that fills one bottle at a time.
Brenda dips each cork into sanitizing solution, and then, using a sort of countertop-mounted reverse corkscrew, muscles it into a bottle by hand. Next comes the trickiest part: gluing the distinctive Tucker Hill Winery label on just right, one bottle at a time.
Tucker Hill is a player in Iowa's current winemaking boom. Ten years ago Iowa had only eight or 10 wineries, most of them in the Amana Colonies, making wines largely from fruit juices and honey, according to Craig Tordsen, Iowa State University's value-added rural economic developer.
Today, Tucker Hill is one of the 81 wineries licensed in Iowa. Their so-called ''native wines'' make up 5.2 percent of all wine sales in the state and now account for $11.7 million in sales. The industry is also an economic force for agritourism. Many wineries, including Tucker Hill, offer wine tasting events and have a wine shop and party room available for celebrations, receptions, reunions, after-hours business meetings and other functions.
Northwest Iowa is the last region of the state to get into the highly entrepreneurial winemaking business. The Dittmers' winery is one of just two licensed in the region. The other is Hannel Cellars in Sioux City, which had produced 300 gallons this year by the end of June.
Valiant Vineyards Winery at Buffalo Run Resort is a long-established winery in nearby Vermillion, S.D.
Each region of Iowa, except for the Northwest, has a wine trail - a series of neighboring wineries that cooperate to offer package tours, tastings and entertainment. The events make for a pleasant weekend outing without the plane ticket to California.
According to Mike White, the Iowa State University Extension Service viticulturist, reasons for Iowa's burgeoning wine industry are several:
-Americans' interest in wine skyrocketed after a Nov. 17, 1997, ''60 Minutes''' broadcast about how the French routinely feast on rich food with apparent impunity with respect to its poor health effects, which are allegedly offset by their habit of washing it down with wine.
-The development of new varieties of high quality, cold-hardy, disease-resistant grapes - Cabernets, Merlots, American-French grape hybrids - by the University of Minnesota and Cornell University, makes it possible to grow good wine grapes in Iowa.
-A number of adults are returning to family farms in Iowa., many after living in California. Now they have land, some money and a taste for wines.
-The rising popularity of hobby winemaking; wine- and beer-making are second only to gardening among America's most popular hobbies.
-Wine consumption is growing all over the world; a 2.1 percent increase is forecast for the United States next year.
-Iowa's lenient tax laws. Wine consumed at the wineries is not taxed. The tax is just $1.75 per gallon on retail wine sales.
Iowa State University and the ISU Extension Service provide a wide range of services to the booming Iowa wine industry. Iowa has more than 400 vineyards, and White works full time with grape growers and wineries on growing practices, financing and marketing - everything but making the wine. He held his first meeting with people interested in growing wine grapes or making wine on Feb. 19, 2000; 125 people attended, representing nearly every county in Iowa. That's when he knew the nascent industry warranted attention.
ISU established the Midwest Grape & Wine Industry Institute in 2006 and now has a commercial wine laboratory and a full-time enologist - a scientist who deals with wine and wine-making, production and quality - Dr. Merli Dharmadhikari. Dharmadhikari, whose lab tests wines for flavor, flaws and sensory perception, said the quality of Iowa wines is improving.
''This is reflected in the increased sales and increases in the number of awards that Iowa wines are winning in various competitions,'' he said. ''This is a new industry and we have barely scratched the surface in terms of the industry's potential growth.''
Dr. Paul Domoto is an ISU horticulture professor who researches grapes with an eye to the best varieties to grow in Iowa. He said some Iowa soils, mostly in north central and Northwest Iowa, are too rich for wine grapes. Soil with 2-3 percent organic matter is ideal, but some Siouxland soils run up to 4 percent organic. (The remainder is minerals, held together by the organic matter.) And too much nitrogen, which is good for corn, means winter die-off for grapevines. Good grape-growing soil should also be classified as ''well-drained.''
Craig Tordsen, the ISU Extension's value-added rural economic developer, guides producers on the business side. Working from his Sioux City office, he helps vintners make their wine-making profitable.
Barry and Brenda Dittmer both work for Weinrich Truck Lines, Brenda's family's business. But a seed was planted 10 years ago when Brenda and their children gave Barry a home winemaking kit. Like other enthusiasts, he started thinking on a larger scale.
It would be fun, and besides, he could write off his tractor, truck, mower and the building where he stored them. He went to Iowa Wine Growers meetings, talked to producers, read books. He can write off his equipment now, he jokes, but it sits outside. The winery occupies the former storage shed.
The Dittmers planted their first half-acre of vines in 2002 and another half-acre the next year.
''It takes three years for the roots to grow,'' Barry said. ''Then the vines grow like weeds.''
They picked a few grapes the third year, and the fourth year promised a good crop until birds ate the grapes. He tried bale netting to keep them out, but it was too flexible.
Last year he bought special, stiffer, vineyard netting and got a ''really big'' crop.
The Dittmers finally opened Tucker Hill to the public last spring, on May 29. More than 300 people attended their initial open house weekend. And within the first few months their guest book was signed by visitors from 22 states and two other countries - Switzerland and Puerto Rico.
That first week alone they bottled 800 bottles of wine. ''That's a lot!'' Brenda said.
Now they make seven different wines from Iowa-friendly grapes such as Esprit, Niagara, Marechal foch, Landot and Frontenac. The most popular of their blended wines is Sweet Royal Blush, a sweet wine made with Merlot grapes and strawberry flavoring.
So, it's not Napa Valley. At least not yet.