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Ardure Wines winemaker Jason Ruppert ferments and ages his wines with crystals, a practice rooted in spirituality, not science. 

Jason Ruppert places a rose quartz crystal at the bottom of his amphora before filling the clay container with his wine.

A bottle of Ardure Wines 2021 Beveridge Vineyard Zinfandel from the Dry Creek Valley next to a rose quartz crystal and the lid to an amphora.

Natural winemakers try to limit what they add to wine during fermentation like yeast and sulfur. But one Sonoma winemaker is breaking this custom with one unorthodox addition: crystals. 

Since 2018, Jason Ruppert, owner of small natural winery Ardure Wines, has added crystals like rose quartz, labradorite and fluorite to his wines while they ferment and age. His goal? Add some extra “good vibes” to each bottle. 

“People are stressed out,” Ruppert said. “We’re all really tired, and any extra vibration — any extra intention — behind the product is worthy.”

It’s also out there. 

Until recently, Ruppert was a lone wolf in his approach — not that it bothers him. Most winemakers, even many of Ruppert’s natural wine brethren, would raise an eyebrow at the idea of crystal fermentation. 

“I think the first reaction was, ‘This is the most Northern California thing we’ve ever seen,’” said Ed Feuchuk, the vice president of marketing at Calistoga’s Tank Garage Winery, which, like Ardure, has developed a following for its experimental approach to winemaking. 

A rose quartz crystal sits at the bottom of a clay amphora, which is being filled with a wine made with a blend of Frontenac and St. Croix varieties for Ardure Wines.

Ruppert admits his process is rooted in spirituality, not science. He hasn’t performed trials to prove definitively if and how crystals impact wine, but he believes there’s a key and noticeable difference. And it may not be as woo-woo as it sounds. 

Ruppert believes Egyptians, Greeks and Romans sometimes placed precious gems and crystals in goblets of wine to help increase potency. Quartz is commonly found in vineyard soils, and many believe this brings a mineral quality to the wines. (The scientific merits of that theory have been fiercely debated.) And one of the most important preparations used in biodynamic farming involves finely ground quartz crystal placed in cow horns. The horns are buried in the ground to enhance photosynthesis; quartz absorbs and radiates light. 

Before starting Ardure, Ruppert worked as a sommelier for the restaurant group behind three-Michelin-starred Atelier Crenn and the now-defunct restaurant Molina in Mill Valley. He has been fascinated by crystals since he was a child, referring to himself as “a complete rock hound” and collector.  

“You can believe in it or not, but the wines always have a certain amount of vibrancy and people gather that regardless of knowing it’s been made with crystals or not,” he said, noting that watches have long relied on quartz for its ability to generate frequencies.

Ruppert still considers his craft zero-zero winemaking, the extreme of natural winemaking where absolutely nothing extra is added. The crystals, he said, are nontoxic, natural elements that don’t affect the chemistry of the wine. Ruppert believes they actually bolster the wine’s “natural integrity.”

Each harvest, Ruppert uses the same set of crystals for fermenting a range of grape varieties like Zinfandel, Chardonnay and Muscat Canelli, which is used to make an orange Pet Nat. He also sources hybrid grapes from the backside of the Tahoe Rim in Nevada; it’s another way he’s challenging conventional winemaking standards.

Ardure Wines winemaker Jason Ruppert holds one of his shungite stones, which he places over the tops of his amphora for "an extra layer of protection" from bacteria and electromagnetic fields (EMFs). 

He puts the crystals in the bottom of clay amphora, an ancient winemaking vessel that originated in the country of Georgia and has recently regained popularity. The crystals remain in the amphora for fermentation and then for roughly 11 months of aging. Rupport also places black shungite spheres on top of each vessel as an “extra layer of protection.” Extremely rare and made of carbon, shungite is used to repel bacteria and electromagnetic fields (EMFs). “Tech is everywhere around us, and EMFs are somewhat harmful in excess,” said Ruppert, who has shungite next to his TV at home. 

Once he bottles a vintage, Ruppert washes the crystals in a saline and water solution before burying them in his garden to “recharge” on the full moon. At the next full moon, he finishes charging them under the moonlight for three days, where they “gather celestial energies.”

“They’ve been working for 11 months and are really tired,” said Ruppert. “The wine has essentially drained their juice. It’s like charging a battery.”

When Tank Garage Winery, which specializes in experimental, one-off blends, learned of the crystal fermentation process, the team was intrigued and invited Ruppert to talk to them about it last year. Feuchuk called it “one of the most impassioned speeches we’ve ever heard,” and from there, Tank decided to try Ruppert’s method. Owner James Harder even approved a substantial “crystal budget” for the endeavor.

Tank’s first crystal release from the 2021 vintage will drop Oct. 14. There are 85 cases of Crystal Visions ($75) — a Cabernet Sauvignon from San Benito County — which gets its name from the compilation album by Fleetwood Mac singer Stevie Nicks.

Tank winemaker Bertus van Zyl selected this Cabernet for the crystal project because it was already a bit of a renegade. “It was something so against the grain of traditional California Cabernet. It’s more savory, spicy, herbaceous,” said van Zyl. “So we thought, ‘Why don’t we lean into this?’”

Leaning into it meant processing the Cabernet differently from what’s traditional. Van Zyl fermented the Cabernet clusters with the stems versus berries only, a process more common with grapes like Pinot Noir or Syrah. Stems can add spicy tannins and sometimes green vegetal notes, which many Cabernet producers seek to avoid. The team then foot stomped the grapes, a common approach in the natural wine world that’s gentler than mechanical crushing.

Tank placed some crystals in the fermentation bins for the roughly 26-day fermentation process, and then staged others around the bins and barrels. Van Zyl aged Crystal Visions in neutral oak — another rare approach with Cabernet in Napa, which typically relies on new oak. Tank will release this wine just one year after the grapes were picked, whereas most Cabernet ages in the barrel for a few years. 

The winery plans to use the crystals again this harvest, but with different grape varieties.

“Experimenting is what we do here,” Feuchuk said. “We’re not presenting this as conclusive scientific data. What the crystals did to it, that's up to the wine drinker to decide.”

Jess Lander is a San Francisco Chronicle staff writer. Email: jess.lander@sfchronicle.com Twitter: @jesslander