Diamond Mountain District · Napa Valley
Visit Theorem with a Private Chauffeur
A restored 19th-century homestead on Diamond Mountain making single-vineyard, single-varietal wines, and a suggested six-hour day of tasting around it.
Book a Six-Hour Wine Tour
About the Winery
Kisha and Jason Itkin, a Houston couple, founded Theorem in 2012 on a neglected estate on Diamond Mountain, just outside Calistoga. The land was homesteaded in 1880 by Dr. Richard Beverly Cole, a San Francisco physician. Over about ten years the Itkins restored the Victorian home, the schoolhouse and the Long Barn, and in 2018 they added 34 acres on Moon Mountain, on the Napa and Sonoma county line.
Theorem makes single-vineyard, single-varietal wines, one block and one grape, never a blend. The Diamond Mountain vineyard sits at about 1,100 feet and keeps Clone 8 Cabernet Sauvignon vines planted in 1985. The first vintage, 2012, came from deer-damaged vines and yielded only a small crop; it became the flagship Voir Dire, a nod to Jason's work as a trial attorney.
Visits are by appointment and kept small, private and unhurried. Guests walk the historic farmstead and taste the estate wines with a chef-made plate of cheese and charcuterie, served with accompaniments grown on the estate and at Theorem Ranch. The winery also arranges tailored experiences for private groups.
Tasting Fees
The estate tasting includes a walk of the historic farmstead and a chef-crafted cheese and charcuterie plate. Theorem does not publish its tasting fee online; your chauffeur confirms the current fee when making the reservation.
Tasting fees as of September 2026. Wineries set and collect their own fees, and they change from time to time.
At a Glance
Location
255 Petrified Forest Road, Calistoga
AVA
Diamond Mountain District
Visiting
By appointment only. Weekday visits can be booked online; Friday to Monday visits are booked by contacting the winery.
Known For
Single-vineyard, single-varietal Cabernet Sauvignon from Diamond Mountain and Moon Mountain
Founded
2012 (estate dates to the 1880s)
Good to Know
Visits are private and by appointment, with no walk-ins. Members of the Keepers of the Key program get priority for Friday to Monday visits. Private group experiences are arranged directly with the winery.
A Suggested Six-Hour Day
Pickup at 10:00 a.m. from a nearby hotel such as Indian Springs Calistoga or Solage.
10:00 · Pickup at Indian Springs Calistoga or Solage
Stay close and the tasting starts right away. Indian Springs Calistoga, a historic resort with thermal mineral pools on Lincoln Avenue, is about 5 minutes from Theorem, and Solage, an Auberge resort and spa on the Silverado Trail, is about 8 minutes away. The day below fits a six-hour tour, and extra time can be added by the hour.
10:15 · Theorem Vineyards
A private visit to the Diamond Mountain estate, with a walk of the restored farmstead and a tasting of single-vineyard wines with cheese and charcuterie. Allow about 90 minutes.
12:00 · Spire Collection
About 10 minutes away. The Calistoga estate of the Spire Collection, on Bennett Lane north of town, where the seated tasting is built around your preferences. The Seated Tasting is $75 for five wines, about an hour. Prepaid reservation required, for 1 to 6 guests.
1:10 · Lunch at Sam's Social Club
About 8 minutes away. Lunch at Sam's Social Club at Indian Springs, a seasonal farm-to-table restaurant serving lunch Monday to Friday and brunch on weekends, both until 2:30 p.m. Prefer a picnic? We can arrange a catered picnic at a winery that allows one; the cost is quoted when you book.
2:25 · Jericho Canyon Vineyard
About 12 minutes away. A canyon estate at the base of Mount St. Helena, with steeply terraced vineyards and a cave winery. The Private Estate Tasting is $100 and runs 60 to 90 minutes, with a vineyard tour and a walk through the caves; we plan on about 75 minutes. By appointment, up to 10 guests.
3:40 · Back to your hotel
Back by 4:00 p.m., six hours after pickup.
Optional: Maria Concetto Winery
Adds about an hour. A downtown Calistoga tasting room on Lincoln Avenue, opened in 2020, pouring limited-production Cabernet Sauvignon, Pinot Noir and Bordeaux-style reds. Walk-ins are welcome (appointments are encouraged), with tastings from $40 to $65. Open until 6 p.m. (8 p.m. Friday and Saturday); closed Tuesday and Wednesday.
About $175 per person in tasting fees at Spire Collection and Jericho Canyon Vineyard, plus Theorem's estate tasting fee (confirmed when we book), paid directly to each winery.
Theorem books weekday visits online and Friday to Monday visits by contacting the winery. Maria Concetto is closed Tuesday and Wednesday (it opens at 1:30 p.m. Monday and 2:30 p.m. Thursday), so on those days the optional stop moves to another walk-in room.
Every tour is custom. This day is a starting point: your chauffeur will shape it around what matters to you, and we plan multi-day tours for guests who want to see more of wine country.
Your Vehicle & Six-Hour Tour Rates
Up to 6 guests
Elite Luxury SUV
Lincoln Navigator or Cadillac Escalade
From $750
Six-hour wine tour, plus 20% gratuity. Additional hours $125 each.
Up to 9 guests
Jet Sprinter or Executive Luxury Van
Captain's chairs and room to spread out
From $1,350
Six-hour wine tour, plus 20% gratuity. Additional hours $225 each.
Larger groups travel in more than one vehicle, and we plan the winery appointments around your group, since many wineries limit groups to 6 to 8 guests. Tasting fees are separate and paid directly to each winery. Every tour starts with six hours; add time by the hour when you book.
Questions
Do I need a reservation at Theorem?
Yes. Theorem is open by appointment only, with no walk-ins. Weekday visits can be booked online, and Friday to Monday visits are booked by contacting the winery. When you book a tour with us, your chauffeur makes the reservation for you.
How much is a tasting at Theorem?
Theorem does not publish its tasting fee online; the tasting includes a chef-crafted cheese and charcuterie plate, and your chauffeur confirms the current fee when booking, as of September 2026.
What is Theorem known for?
Single-vineyard, single-varietal wines, especially Cabernet Sauvignon from Clone 8 vines planted in 1985 on Diamond Mountain, plus wines from its Moon Mountain property on the Napa and Sonoma line.
Who owns Theorem Vineyards?
Kisha and Jason Itkin, who bought the Diamond Mountain estate in 2012 and spent about ten years restoring it.
What is the history of the Theorem estate?
Dr. Richard Beverly Cole, a San Francisco physician, built the homestead in 1880. The Itkins restored its Victorian home, schoolhouse and Long Barn.
How does booking a tour with Bien Chauffeured work?
Reserve a six-hour tour online, even if your plans are still taking shape. Your chauffeur will email you first to learn what matters to you, then build your itinerary and make the winery appointments. Extra hours can be added.
Reserve Your Tour Now, Plan the Details Later
Your plans don't need to be final to book. Reserve your six-hour tour online, and your chauffeur will email you first to learn what matters to you, then build your itinerary and make the winery appointments. Prefer to talk? Call our concierge at 888-291-2328.
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