Rodney Strong Vineyards’ fermenter is the only one of its kind in the US

Half French oak, half stainless steel, this egg-shaped fermenter is a new experiment for Rodney Strong Vineyards.|

Who hatched this new breed of egg-shaped fermenter?

The 4-foot oblong fermentation vessel in the cellar at Healdsburg’s Rodney Strong Vineyards is a prototype produced by Vicard, a barrel-making company in Cognac, France, and the only one of its kind in the United States.

While concrete eggs for fermentation are common in high-end winemaking, this hybrid is different; it’s half French oak and half stainless steel.

“The plan is to buy more of those and bigger ones, too,” said Justin Seidenfeld, senior vice president of winemaking and winegrowing for Rodney Strong. “It would always be used for something on the higher tier because of the cost.”

The egg is priced at roughly $8,500, and Seidenfeld said the winery is just making one wine with it — the Cooley Ranch chardonnay in the Rowen portfolio.

The hybrid egg is expected to be a popular winemaking tool. Seidenfeld expects it to be on the market in early 2024.

“You get the benefits of the two materials,” Seidenfeld said. “Freshness comes from the steel, which makes the wine fruity and vibrant. And you get richness and mouthfeel from the oak.”

The shape of the egg allows carbon dioxide, a byproduct in the fermentation process, to move through it naturally.

“You really get beautiful kinetics during fermentation,” Seidenfeld said. “You don’t have the stratification you get in a stainless-steel tank, where the top of the tank is going at a different pace than the bottom of the tank because of the differences in the way things move.”

The prototype, like concrete egg-shaped fermenters, is based on ancient vessels used for wine. According to Wine Folly, which cites the National Academy of Sciences, these oblong containers date back to the Stone Age, 8,000 years ago. Even then, winemakers realized the egg shape allowed for constant movement and continuous flow of currents that influence tannins and acids.

Seidenfeld talked about why the egg’s ancient past is noteworthy and why it’s crucial to experiment with fermentations and every aspect of winemaking,

Question: What do you find most fascinating about the fact that egg-shaped fermentation vessels date back to the Stone Age?

Answer: It proves the benefit of fermentation in this kind of vessel because it has truly stood the test of time. The core benefit of the egg is that it naturally controls the temperature rather than artificially controlling the temperature with jackets on stainless-steel tanks. It allows for a natural fermentation.

Q: Why do you think this prototype — half stainless steel and half French oak — is a cut above concrete eggs?

A: The dual materials allow for more balance of a finished wine. You get a more integrated wine when it’s finished. ... The shape of the egg is great for both, but the dual materials are better for the style of wine I’m trying to make.

Q: Were you pleasantly surprised by how the Cooley Ranch chardonnay turned out?

A: Absolutely. My philosophy with living life and making wine is surprise and delight. And when I tasted the wine, it was truly a surprise-and-delight moment.

Q: Why is experimenting with new ways of fermenting and all aspects of winemaking crucial?

A: Because it’s pushing our boundaries. Oliver Wendell Holmes said, “A mind that stretches by a new experience can never go back to its old dimension.” So based on that concept, if we didn’t experiment, we’d be destined for mediocrity. And we always want to be at our best.

You can reach Wine Writer Peg Melnik at 707-521-5310 or On Twitter @pegmelnik.

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