From grape to glass: Penn State enologist supports Pennsylvania winemakers

With a swirl, sniff and a sip, Denise Gardner, Penn State’s enologist, can discern almost all there is to know about a particular variety of wine. Though she’s trained to pick up on even the most subtle notes of vanilla or cedar in a chardonnay or merlot, Gardner’s no snob: She says her favorite kind of wine is the one in her glass.

As the University’s resident enologist — a person who studies the science of wine and winemaking — it’s her job to help Pennsylvania wineries and winemakers perfect their grape-to-glass blends.  

“I spend my days educating local industry members about wine styles, how to incorporate sensory analysis into their processes and to identify problems and opportunities in their winery operations,” said Gardner, who worked in France and California before joining Penn State Extension. “I am trained in the chemistry and microbiology of wine, so if a winery has a question and can’t find an answer, I’m usually one of their first points of contact.”

Penn State Extension is an educational network that gives community members and businesses access to a broad range of agriculture-related resources and expertise. As part of this mission, Gardner and her viticulture colleagues in the College of Agricultural Sciences use a variety of technology for researching and testing wine in campus labs and for teaching winemaking to students in the University’s food science program. They also connect with industry members in 67 Pennsylvania counties via educational workshops and their popular Wines and Grapes U. blog.

As a popular destination for winemakers and wine enthusiasts, Pennsylvania is the nation’s fifth largest producer of grapes with more than 14,000 acres dedicated to growing the fruit. According to the Pennsylvania Winery Association, the wine industry contributes $1.9 billion annually to Pennsylvania’s economy and brings more than a million tourists to the state’s roughly 250 wineries.

Since high school — when she first learned about a pest that nearly decimated Europe’s wine industry in the 1800s — Gardner has been passionate about helping winemakers navigate the complexity of the winemaking process.  

“Winemaking is an art and a science. Each season’s batch is different, and the work that goes into creating the flavors you want varies based not only on the type of grape, but the climate, weather, soil, pests and disease that particular year,” Gardner said. “The process is still very hands on and traditional in the sense that decisions have to be made on the fly, and years of experience, knowledge and palate count for so much. You hold on to the vintage years that are the greatest, and then others you do the best you can to make a more typical style.”

Once a year, each of Pennsylvania’s (mostly boutique-sized) wineries start the process by deciding when to harvest their grapes, usually in September or October. After being picked, the fruit is crushed within 24 to 48 hours before being placed in fermentation tanks where alcohol is derived from the grapes’ sugar. Next, the wine is placed in oak barrels or steel tanks to be clarified: a process in which tannins, dead yeast cells, and proteins are extracted through fining and filtration. To age, the wine goes back into oak barrels (to develop a smooth, round flavor) or steel tanks (for fruitier whites) before being bottled.

Because the entire process can take six months for a white or rosé and years for certain reds, Gardner says it’s difficult to automate. Unlike beer, cider and milk — in which it’s possible for a computer program to move a product through a series of steps like clockwork — wine is much more variable in how it’s created and, ultimately, tastes.

One of the ways Gardner helps winemakers streamline the inherent variability of their craft is through sensory analysis, in which chemicals in wine are analyzed through a series of tech-infused science experiments. The process involves measuring the sugar and acid concentration of grapes before they’re picked as well as the wine’s nutritional content, sugar, sulfur dioxide, acetic acid, and yeast microflora, along with other metrics. Some wineries also use automated systems such as autotitrators (to test pH and/or acidity) and analyzers to assess various chemical constituents.

“Sensory analysis helps us test consumer taste preferences, identify trends, evaluate the differences between wines, and characterize wine flavors and aromas,” Gardner said. “By enabling winemakers to measure the differences in their products from year to year, sensory analysis helps them incorporate numbers-based decision-making into their processes.”

For example, having access to analytics can help a winery decide when to pick their grapes in a particularly hot or cold season, which has a ripple effect on the outcome of that year’s wine.  

“We had a really, really dry year in 2010, and almost none of the winemakers in the state had ever dealt with a situation where they saw such aggressive and fast ripening,” Gardner said. “Based on some of the data that year, everyone picked earlier than was optimal and a lot of high alcohol, very fruity red wines suddenly emerged. You just have to go with it.”

Gardner, a frequent traveler, leads workshops in wine cellars, tasting rooms and labs across the state, and she and her colleagues publish how-to and research articles on their blog and share updates via Twitter and Facebook posts, which she says reach nearly every industry member in the state (and as far away as South Africa and Australia).

“The grape growers and winemakers in Pennsylvania are some of the most talented people I know,” Gardner said. “From year to year, they don’t know what kind of weather they’ll be up against, like they do in California and Australia for example, and they have to continuously adapt. Sensory analysis and analytical testing are valuable resources, but ultimately, no number will be able to tell you what to do to make quality wine or production decisions.”

In recent years, Gardner says there’s been a boom in the number of wineries opening across the state thanks to increasing market interest, quality improvements and wines that adhere to global styles.

“In Pennsylvania, you’re never more than an hour away from the closest winery and there’s something for everyone. We have such a variety of grapes here — from chambourcin and gruner veltliner to muscat — that each winery is able to add their own touch and truly develop a signature style,” she said. “And because wine is a reflection of the year and place those grapes are grown, each glass of Pennsylvania vintage is like a little piece of history.”

Media Contacts: 
Last Updated November 02, 2016