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Director Meets Industry, 600 and Growing, pH Balancing

Posted by | April 16, 2009

Henick-Kling Meets the State

WSU V&E director Thomas Henick-Kling listens as West Side winemakers describe their operations during a meeting at WSU's Northwest Washington Research and Extension Center in Mount Vernon.

WSU V&E director Thomas Henick-Kling listens as West Side winemakers describe their operations during a meeting at WSU’s Northwestern Washington Research and Extension Center in Mount Vernon.

The new director of WSU’s Viticulture and Enology Program, Thomas Henick-Kling, is just completing a whirlwind tour of the state to get better acquainted with the people who comprise Washington’s wine industry. Over the past few weeks, he visited every wine-producing region in the state.

“I am impressed by the enthusiasm and the energy of the people I met all across the state for continuing to refine and expand their industry,” he said. “Even with its success over the past 30 years, the industry remains dynamic and forward looking, and there is plenty of opportunity for significant continued growth.”

As part of his tour, Henick-Kling traveled to Seattle for the industry’s showcase event, Taste Washington, in which more than 200 of the state’s wineries participated. He also toured wineries in the Woodinville area, home to some of the state’s largest producers, and attended a tasting in Mount Vernon featuring wines produced from Puget Sound Appellation grapes.

The Puget Sound area boasts 45 wineries and more than 80 acres in wine grape production. Henick-Kling sees plenty of room for growth in the region.

“The areas with established high potential for growing excellent wine grapes are in eastern Washington along the Columbia River and its tributaries,” he said. “And there are some promising new regions in the Puget Sound area. These sites are small and not suited for large-scale grape production, but they are capable of producing quality grapes for small premium wineries.”

Henick-Kling pointed to the research of University of Southern Oregon climatologist Greg Jones, who has already mapped the area of the Puget Sound for sites well suited to wine grape production.

Regardless of which areas of the state are being considered for new vineyards, Henick-Kling said the key to success is in identifying the best grape varieties for a given region, and adapting grape growing and winemaking practices to refine the flavor profiles of the wines.

“As we learn more about improving cultivation of different varieties and improve winemaking techniques to sharpen flavor profiles, consumers will be able to distinguish the unique flavors of the state’s various grape-growing regions,” he said.

Washington Wineries Top 600

During the past ten years, number of wineries and vineyard acreage have grown fast in the booming Washington wine industry.

During the past ten years, the number of wineries and vineyard acreage have grown fast in the booming Washington wine industry.

Just 10 years ago, Washington’s wine industry was a niche industry with a loyal fan base for its 160 wineries.

Now, Washington has licensed over 600 wineries, marking a nearly 300 percent increase in just a decade.

“It’s great news,” said Robin Pollard, executive director of the Washington Wine Commission. “The natural evolution of our industry, the growth, is indicative of the fact that many people recognize the quality of the grapes that we grow here in Washington, that then can be made into world-class wines.”

Valued at about $3 billion annually, Washington’s wine industry has seen steady growth in the past two decades. The number of wine grape plantings increased from 24,000 acres in 1999 to an estimated 33,000 this year.

Growth in Washington’s industry is expected to continue, said Vicky Scharlau, executive director of the Washington Association of Wine Grape Growers.

“There’s been a nice offset between supply and demand,” she said. “The growers have been very cautious, and we have been very diligent in the message to growers that unless you have a contract with a winery, we don’t recommend planting more acreage.”

Through its research, extension and education, WSU has been a key advocate of the growth of the Washington wine industry since the 1930s. To learn more about WSU’s ongoing role in the industry, please visit:

New Research Sheds Light on pH Balance

Potassium, the must abundant inorganic element in grapes in wine, forms a multitude of salts (bottom) that influence wine's final pH.

Potassium, the most abundant inorganic element in grapes and wine, forms a multitude of salts (bottom microphotograph of salt crystals) that influence wine’s final pH.

Winemaking is a chemical balancing act. Great wine starts in the vineyard, the maestros say, because grapes come to the processing facility with all sorts of variables that need to be reconciled. One of the major concerns in the balancing act is pH. Wine pH is determined by a complex dance between the concentration and strength of various acids and the salts formed by inorganic chemicals, including potassium, in reaction with acids.

If pH is too high, the wine becomes an unstable breeding ground for unwanted micro-organisms and, in addition, color fades and may turn brown during aging. If pH is too low, micro-organism growth is inhibited, but the resulting wine may be too sour to enjoy.

Since potassium is the most abundant inorganic element in grapes and wine, understanding its role in the pH act is crucial to making great wine. Winemakers have long been concerned that long skin contact times increase fermentation – but does it really? Until recently, there was no commercial-scale experimental evidence one way or the other.

Enter WSU research enologist Jim Harbertson and his technician, Eric Harwood. In a recent series of cleverly designed and commercially scaled experiments, they shed considerable light on the question of just where potassium comes from – and goes – during grape crush and fermentation. Their work, recently published in the American Journal of Enology and Viticulture, suggests ways that winemakers can control potassium, and thus, final pH.

During maceration, in which grape skins remain in contact with juice, the researchers showed that potassium declines during pomace contact time and is later recoverable from the berry skins. (Pomace is the solid remains of the fruit after pressing.)

What’s happening, the researchers suggest, is that the skins of the grapes, although rich in potassium to begin with, are adsorbing potassium during their contact time with the must. Potassium is reacting with complex carbohydrates called polysaccharides in the pomace skin, and acting as an ion-exchange resin. An ion-exchange resin is a highly porous, complex structure that easily traps and retains ions. And ions are key in the formation of the salts that play a significant role in final pH.

Further, this dance of ions can be controlled. The researchers found that potassium extraction from grape skins was limited by the concentration of potassium present in the juice (pulp) and the concentration of ethanol in the must. The main source of potassium in the wine was from the pulp. Several smaller scale experiments confirmed the results found on a commercial scale by taking grapes harvested from the same vineyard and experimenting with different concentrations of potassium and ethanol.

Results also suggest that juice treated with pectinase while skins are present likely increases the potassium content of the finished wine and potentially increases the pH. Winemakers routinely use pectinase enzymes to improve juice yield and color extraction and thus may be liberating potassium from the pomace. To better understand this potential twist in the balancing act, Harbertson and his team are conducting further research.