03/29/2012 12:30 EDT | Updated 05/29/2012 05:12 EDT

WINE TECH: Fans say oval fermenters make egg-ceptional wines

NAPA, Calif. - Do you like eggs with wine? How about wine IN eggs?

Sounds a bit dicey, but it's been happening more lately as winemakers embrace concrete egg-shaped fermenters as a way to add unique flavours to their wines.

The eggs, which can be two metres tall or higher, have a cuteness factor not usually to be found in farming machinery. In fact, the Domaine Carneros winery in the Napa Valley was inspired to get in the seasonal spirit and had their 900-kilogram egg decorated for Easter complete with a frieze of white bunnies.

Despite appearances, there's a serious side to this fresh approach. And it all starts with permeability.

Stainless-steel tanks, which allow no oxygen in, create bright, sharp flavours. Wooden barrels, which are quite porous, create a rounder taste with flavours from the oak. The concrete egg fermenters, which fall somewhere between stainless steel and wooden barrels in permeability, offer a third option, says Domaine Carneros winemaker TJ Evans.

"What we get is a kind of an enhanced minerality and a richer texture, but without the oak," he says. "It's a nice little tool that fills in the niche."

Concrete fermenting tanks aren't new. Huge, square ones are to be found in wineries around the world. But they fell out of favour in California with the push to modernize during the '70s and the move to stainless-steel tanks.

But concrete has quietly been making a comeback.

The Domaine Carneros fermenter, which has walls about 7.5 centimetres thick and holds about three barrels worth of wine comes from a French manufacturer, Nomblot, which has been making egg-shaped fermenters for more than a decade.

About four years ago, a U.S. producer, Sonoma Cast Stone Corp., based in Petaluma, also cracked the market.

The company has been making modular concrete fermenting tanks for some time and company president Steve Rosenblatt, who grows grapes himself, decided to try the different shape after his own winemaker asked him about it. In addition to the oxygen factor, the tapered egg shape condenses the gases given off during fermentation, keeping the wine rolling, which is believed to be beneficial, he says.

Rosenblatt, who can't help but think of the fermenters in a dairy context, says he sold a dozen his first year and three dozen last year.

Getting the egg shape right is a technical challenge, but there's no denying it amps up the decorative factor. Sonoma Cast Stone, which makes some large eggs in black or dark brown, which give off a fun, sci-fi aura, was recently commissioned to make two concrete eggs, one red, one yellow, for wineries that want to show off their unique tanks.

Another Napa Valley winery using the egg-shaped fermenters is CADE. When the winery bought the eggs, also from Nomblot, they weren't sure what to expect, says winemaker Tony Biaggi. But "all fears were put to rest when we tasted the first wines fermented in them."

The egg-fermenters are used to add nuance to CADE sauvignon blanc. Though the egg-fermented wine amounts to only six per cent of the final blend, it adds interesting layers, says Biaggi. "The wines fermented in concrete eggs seem to be alive and full of energy."

Domaine Carneros is best known as a producer of well-regarded sparkling wine, but the egg fermenter is being used to make a fairly unique still wine, Pinot Clair, which is a white wine made from the red-skinned grape Pinot Noir. Colour comes from skin contact with the juice, so this wine is kept clear by gently pressing the juice out of the grapes and putting the juice straight into the egg.

Giving an Easter spin to the egg was something that Eileen Crane, founding winemaker and president of Domaine Carneros, thought would be a lighthearted touch.

"It's the season," she says. "It just seemed like a fun thing to do."



Domaine Carneros:


Sonoma Cast Stone: