New approach for concrete wine tank

Sonoma Cast Stone designs lighter and more flexible ‘egg’

[caption id="attachment_24148" align="alignright" width="343" caption="Thomas George Estates received the first Sonoma Coast Stone egg-shaped tanks Aug. 12."][/caption]

PETALUMA -- From what was once the egg capital of the U.S., Sonoma Cast Stone is trying to crack into a developing market for egg-shaped concrete wine fermentation tanks by producing a larger, lighter-weight alternative to the dominant French version.

Wine has been found to be made in concrete vessels dating back to Roman times because the material can “breathe” almost as well as wood but doesn’t contribute “oakiness.”

Burgundy-based Nomblot has been a major supplier of concrete tanks of various sizes and shapes to the U.S. wine industry since 1922 and sells 60 to 70 containers a year here, according to Jerome Aubin, whose Oakland-based Artisan Barrels has been importing the containers since late 2007.

Nomblot egg-shaped tanks first arrived in the North Coast in 2003 at Rudd in Oakville. Local users today include Quintessa, Harlan, Vineyard 29, Williams Selyem, Flowers and Gallo. The most popular size is 118 gallons, which weighs 2,600 pounds and costs about $4,500 plus shipping and staging from the American Canyon warehouse. Next is a 422-gallon tank that weighs 6,600 pounds.

Sonoma Cast Stone in 2008 said it was developing a 118-gallon egg tank, but decided to go larger and lighter after talking to vintners.

“We had a number of winemakers come in and help us design this,” said owner Steve Rosenblatt.

Requested options were stainless-steel tubing embedded in the concrete walls of the vessel for raising and lowering the temperature inside, a door at the bottom to remove red-wine pomace or allow easier cleaning, a stainless-steel forklift pallet for relocating the tank, a sling to move the tank by crane if needed, racking and tasting valves, and the ability to attach to the legs casters for easy movement or anchoring bolts to make sure they don’t topple in a temblor.

Sonoma Cast Stone’s egg-shaped containers are about 8 feet high and 5 feet wide, hold 500 gallons and weigh 3,900 pounds dry. They cost about $12,000, including shipping to wineries in Sonoma and Napa counties.

The company lightened the tank by making two eggs in one. Inside is traditional concrete, cast smooth with Portland cement, chlorine-free water and local sand and gravel. Tartaric acid treatments keep the basic pH of the concrete from affecting wine acidity.

Outside is EarthCrete, a proprietary fiber-reinforced mix made from locally recycled concrete, porcelain and glass. It can be given one of several pigments and stamped with the winery logo. All products have shifted to EarthCrete in the past six months.

The first of 13 tanks sold so far arrived Aug. 12 at Thomas George Estates in Russian River Valley, followed by Cliff Lede in Napa Valley’s Stags Leap district, Stone Edge Farm in Sonoma Valley, Wind Gap in Forestville and Cline Cellars, which plans to display one at the Sonoma Valley Wine Auction. One also is bound for Southern California.

Kale Anderson, associate winemaker for Cliff Lede, was an early adviser on Sonoma Cast Stone’s egg. The 20,000- to 25,000-case-a-year winery uses four 118-gallon Nomblot egg tanks in a 5,000-case-a-year sauvignon blanc blend. The beer industry long has been using rounded tanks that allow “convection currents” from fermentation gasses to evenly and gently mix ingredients, he said.

“We’ve been impressed with the results and liked the mouth feel as well as the roundness in the mouth and the nice expression of minerality in our wines,” Mr. Anderson said. “We turned to Sonoma Cast Stone to make something better.”

The winery is testing whether the larger container could make concrete fermentation more cost-effective. The larger Nomblot eggs would require crane rental to relocate in the winery.

Sonoma Cast Stone also reached out to Pax Mahle, who since 2005 has been using six of the smallest Nomblot eggs at Pax Cellars and then his new 2,000-case-a-year Wind Gap Wines in Forestville.

“We’re a bootstrap winery, so space is at a premium,” he said. “To go vertical to ferment more juice in the same footprint is more economical.”

His white wines are fermented in concrete, stainless-steel and French oak containers, and he wants to do more in the latter. A $21-a-bottle Russian River Valley trousseau gris is made completely in concrete.

Sonoma Cast Stone has a sales representative for Australian and New Zealand wine markets to keep the factory busy year-round. If egg sales are successful, the 27-employee company will need to expand its factory, according to Mr. Rosenblatt.

The company has survived hard economic times by shrinking from 42 people in early 2009 and working on public projects such as libraries.

For more information, call 888-807-9117 or visit

Show Comment