Food Science

UC Davis seeks to turn little water into wine

UC Davis student Eric Hildretch, 21, loads grapes into a hopper before they are crushed to make wine at the UC Davis teaching and research winery on Thursday. The university’s Department of Viticulture and Enology aims to reduce the water it uses in its wine production by as much as 90 percent.
UC Davis student Eric Hildretch, 21, loads grapes into a hopper before they are crushed to make wine at the UC Davis teaching and research winery on Thursday. The university’s Department of Viticulture and Enology aims to reduce the water it uses in its wine production by as much as 90 percent. mlear@sacbee.com

The main vineyard at the University of California, Davis, currently relies on 4 to 6 gallons of water to produce each gallon of wine. As soon as next year, researchers hope new technologies can reduce that vineyard demand to as little as 1 gallon of water per gallon of wine.

As California endures its fourth year of drought, the UC Davis Department of Viticulture and Enology on Thursday showed off its latest attempts to make sure student-produced wine not only remains delicious but also water conscious.

The dry heat in California has sped up wine-grape picking at UC Davis, but the volume remains stable compared to previous years. By the end of the 2015 wine crush at UC Davis, students and staff of the department will have crushed 7,182 pounds of grapes, and they are on course to produce close to 450 gallons of wine out of their 12 acres of vines, located near the main entrance of the campus off Interstate 80.

Wine grapes don’t need huge amounts of water to grow; most of the water the winery uses goes into cleaning the grapes and machinery. To help tackle water use at its source, a clean-in-place system has been installed and is scheduled to be inaugurated in the winery late 2015.

Rather than manually cleaning the production tanks with a hose, a CIP system automatically controls the amount of water needed to reach adequate sanitation levels without waste.

“It’s also safer, because we don’t put people inside the tank (to clean it),” explained David Block, a professor and chairman of the viticulture and enology department.

Water recycling is also a key part of the department’s new research. Students and professors are exploring ways to reuse water from the production and grape-cleaning processes for irrigation of the 12-acre vineyard. Samples of different soils are being combined with water filtered in different ways to determine the best combinations and the most adequate recycling methods, according to Anita Oberholster, enology extension specialist.

Three new 30-foot-tall metal tanks outside the winery are responsible for collecting and filtering rainwater from around campus for use in the winery – and to flush the toilets in the department’s building.

As for the vineyards, a modern irrigation system will avoid water waste by relying on sensors capable of capturing and analyzing humidity levels.

“These sensors will determine if the soil needs water and how much water each separate vine needs,” Block said.

The mechanical engineering department is building a student-designed robot to cut the large amount of water used to hose grape peels off the floors and into the proper drains. The robot instead physically pushes peels into the right spots without using water. Students have already tested their design and applied for a patent.

But at the end of the day, taste remains a dominant factor.

“If it doesn’t make good wine, then why bother?” said Charles Brenneman, the department’s winemaker.

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