Grape Expectations

Precast concrete serves up ideal conditions for the wine aging process.

By Leslie Lichtenberg

The art of producing fine wine is an intricate process that is often as reliant on luck as it is on expertise and timing. Although winemakers have little, if any, control over nature, they must steer the harvesting and processing of grapes through a series of carefully supervised steps in order to create a well-balanced, quality wine to be enjoyed by consumers.

The winemakers at Kluge Estate Winery and Vineyard, located in Charlottesville, Va., at the foot of the Blue Ridge Mountains, understand the delicate balance between nature and human finesse that is integral to produce award-winning wines. Wine aging, a process that can take up to two years, is an important precursor to bottling that requires the wine, usually in barrels, to be stored in a temperature-controlled environment. Cool, dark and damp – three elements critical to the aging of fine wines – led Kluge to build a unique wine storage facility more than 20 feet beneath the red clay soil that comprises much of the vineyard’s 50 acres.

“Ideal conditions for wine storage are temperatures somewhere between 55 and 58 degrees with high humidity,” explained Larry Eldredge, an engineer with BU Corp. of Charleston, S.C. “Using this type of underground vault creates the perfect conditions for aging hundreds of barrels of fine wine without having to pay for additional heating or cooling.”

Due to its thermal properties in underground environments, concrete was considered the product of choice for the Kluge Estate wine storage facility, believed to be only the second underground wine cavern in the eastern United States. Permatile Concrete Products Co., the precast manufacturer for the project, utilized precast concrete bridge sections to build the 30-by-12-by-100-foot structure. The units were manufactured at Permatile’s plant in Bristol, Va., then trucked to the vineyard in Charlottesville. Upon arrival at the site, the bridge sections were set into position atop a 4-foot poured-in-place knee wall.

“The segments were fantastic,” said Eldredge. “They were built perfectly to lock together and fit right onto the wall.”

After six of the 21 precast concrete modules were in place, the back closure walls were delivered and set, two per end of vault, for a total of four closure walls.

“On one of the closure walls, we had an arched doorway opening built in,” explained Hank Rainero of Permatile, referring to the large arched medieval doorway created at the entrance side of the vault.

After the first two closure walls were in place, the remaining units were installed leading to the final two closure walls. An L-shaped headwall was installed on top of the entrance side of the wine vault to retain the fill material that would be placed on top of the structure. End slabs on the end of the tunnel opposite the doorway were bolted on to allow for possible future expansion of the wine cavern.

While underground wine aging systems are commonplace in West Coast wineries, the Kluge Estate facility may be the largest precast underground wine storage vault anywhere and the first to use precast concrete bridge sections to build the structure, according to Rainero. “This is an unusual application for this type of product. Typically, these units are used for small-span bridge crossings,” he said.

Unlike similar arched products, which rely heavily on backfill for structural strength, the Kluge Estate wine vault, a three-sided rigid frame structure, did not depend on backfill for structural integrity. This “cut and cover” man-made cave offered the efficient, economical and consistent aging environment the winemakers were looking for.

Man-made caves are the most cost-effective way to store and age wine, according to information posted on BU Corp.’s Web site. Winemakers have begun to construct wine caves where no natural ones exist, particularly in California, home to approximately 100 such storage caves. Because proper aging is essential to helping wines reach their peak, the cool and humid environment inherent in these storage caves appeals to winemakers, and despite a slightly higher initial investment, most well-built underground caverns will pay for themselves in two to four years.

At Kluge Estate Winery and Vineyard, purveyors of Cabernet Sauvignon, Cabernet Franc, Merlot and Chardonnay, approximately 200 barrels – the equivalent to 15,000 bottles of wine – are stored three-deep on racks in the underground wine cavern. The barrel aging process for red wines, a 1½ to two-year process, takes place in French oak and sometimes Virginian oak barrels to impart the perfect blend of flavors in the wines. Underground storage provides an inexpensive means of cooling and humidifying the red wine barrels during this process.

Excavation for the Kluge wine vault began in the winter of 2002 and the project was completed the following summer. The precast modules, which were delivered ready to install, were set in approximately three days.
“We had a bad time initially with the weather,” said Eldredge. “But because the precast bridge segments were a perfect fit, the installation and setting time were quick.”

Having previously built an aboveground facility to store their wines, the winemakers at Kluge Estate were all too familiar with the necessary cooling and maintenance costs associated with this type of system. By delivering a product ready to install and use, Permatile provided a quick and economical alternative to above-ground storage as well as the opportunity to realize significant savings from storing wines in a controlled environment that requires less maintenance and general upkeep.

Project Profile
Project Name: Kluge Wine Storage Facility
Owner: Kluge Estate Winery and Vineyard, Charlottesville, Va.
Engineer/Contractor: BU Corp., Charleston, S.C.
Precast Manufacturer: Permatile Concrete Products Co., Bristol, Va.*

*Permatile Concrete Products Co. is a certified plant under NPCA’s Quality Assurance/Plant Certification Program.