About Diatom
Diatom is a small-production Santa Barbara County Chardonnay label founded in 2012 by Greg Brewer — the acclaimed winemaker behind Brewer-Clifton — at 2901 Grand Avenue in Los Olivos. The name references diatomaceous earth, the fossilized skeletal remains of single-celled aquatic organisms that form the chalk-white, mineral-dense sedimentary deposits found in the Santa Rita Hills and across the Santa Ynez Valley floor. These ancient soils are a defining feature of the Santa Barbara County wine landscape and a primary reason that Chardonnay achieves such extraordinary mineral complexity and natural acidity in this corner of California.
Diatom is a Chardonnay-only label, reflecting Brewer's singular obsession with the variety and his belief that the Santa Rita Hills and broader Santa Barbara County terroir produce Chardonnay of world-class quality when farmed and vinified with the right combination of restraint and precision. The wines are made with minimal intervention — native fermentation, minimal new oak, no manipulation of acidity — allowing the diatomaceous soils and the cool, marine-influenced growing season to express themselves without winemaker interference.
The Los Olivos tasting room on Grand Avenue is open Thursday through Monday from 11am to 5pm with walk-ins welcome and a $20 tasting fee. Grand Avenue in Los Olivos is one of California's most concentrated and charming small-town wine tasting districts, making Diatom an ideal stop on a broader Los Olivos and Santa Ynez Valley wine exploration.
"Diatom is Greg Brewer's purest statement about Santa Barbara County Chardonnay — a single-variety label that strips away everything except what the soil and the season want to say."
Production is small and the mailing list is the primary channel for the most limited single-vineyard releases. For Chardonnay enthusiasts who want to taste what the Santa Rita Hills' ancient diatomaceous soils can produce in the hands of one of California's most thoughtful white wine specialists, Diatom is an essential Los Olivos destination.
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The AtmosphereGenuinely the most unpretentious winery in Northern California. No stuffiness — just great wine, big smiles, and a Lab at your feet.
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Diatom Cabernet SauvignonTheir flagship Cabernet named after the the estate vineyard is exceptional — rich, bold, and shockingly affordable for the quality.
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Family & Dog FriendlyKids get juice boxes and snacks. Dogs roam free. Parents get great wine. A rare trifecta Diatom nails completely.
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True Estate WinesEvery bottle comes from their 150 acres in Carneros — grape to glass on the same property. You taste the place in every pour.
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The GroundsBocce court, picnic tables, farm animals, vineyard views. Bring a cheese board and plan to stay all afternoon.
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Wine Club Value$38/shipment for two bottles with 12 free tastings annually — one of the best value wine clubs in all of Sonoma.
"Where cowboys once competed, great wine now flows."
WinoNotion Score: 9.1 / 10
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Featured Wines
White · Flagship
Chardonnay
Sanford & Benedict Vineyard
Diatom's benchmark — unoaked Chardonnay from one of Santa Barbara County's most celebrated and historically significant vineyard sites. Pure varietal expression without oak interference.
White Wine
Chardonnay
Spear Vineyard
Single-vineyard Santa Rita Hills Chardonnay showing the cool-climate tension and mineral character that this fog-influenced AVA delivers to unoaked production.
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Rita's Crown Vineyard
High-elevation Santa Rita Hills Chardonnay — the most austere and mineral-driven in the Diatom lineup, from an elevated ridge site above the marine fog layer.
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Classic Flight Tasting
Curated flight of current-release wines with knowledgeable hosting. The perfect introduction to Diatom.
$20 · members save
🧺
Picnic on the Grounds
Bring your own food and enjoy the estate setting with a bottle of wine. Walk-in friendly.
Wine by the bottle
🎉
Private Events
Available for private tastings, corporate events, and celebrations. Contact the winery for details.
Inquire directly
🍷
Wine Club Access
Members receive complimentary tastings, allocation priority, and exclusive event invitations throughout the year.
Members only
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