Our Estate Vineyards

Moon Mountain District Sonoma Valley

High on the border between Napa and Sonoma counties, Theorem's Moon Mountain District AVA estate occupies one of the most distinctive and demanding Sonoma Valley vineyard sites in California. Rising from 1,500 to 1,800 feet elevation — near the highest point of the mountain — the vines exist at the edge of what the land will give, and the wines reflect every bit of that struggle.

The 34-acre estate is less than half under vine, with the remainder cloaked in redwood and bay forest that borders the blocks on all sides — a wild, forested setting that is as much a part of Moon Mountain's character as the soils beneath the vines. Acquired in 2018 to expand Theorem's mountain-grown wines collection to include white wines, the property borders Mount Veeder on the east and straddles the county line — a site that belongs fully to neither Napa nor Sonoma, but carries the character of both.

Our Moon Mountain District Estate Vineyard

Small blocks are divided across 14 acres by exposure and microclimate, with planting vintages spanning from 2004 through 2023. The variety selection reflects the Sonoma Valley mountain vineyard’s remarkable versatility: old-vine Sauvignon Blanc captures the site's natural acidity and freshness at altitude; Wente heritage clone Chardonnay thrives in the elevation and ocean-influenced microclimate; experimental plantings of Rhône varietals are taking root, and Cabernet Sauvignon — both young and old-vine clones — find intensity and structure in the shallow volcanic soils.

Old-Vine, Mountain Sauvignon Blanc

Most growers wouldn't plant white grapes here. The slope is too steep, the farming too labor-intensive, the ground too valuable to give to anything but high-priced reds. We do it anyway. Two clones of Sauvignon Blanc, planted in 2004, deliver what the mountain gives back — electric acidity, stone fruit, citrus, mineral tone. Pacific crosswinds sweep the site, moderating temperatures and extending the growing season in ways the valley floor cannot.

Farmed With Restraint

Our Moon Mountain vineyard is farmed sustainably — no herbicides, no pesticides, no shortcut between the mountain and the bottle. Vineyard manager Josh Clark has guided the restoration, reconfiguration, and replanting of this site from the beginning, bringing deep knowledge of Moon Mountain's demands and a shared belief that the land, properly farmed, needs little else. The soils are Clay Loam — shallow, rocky, and demanding — forcing the vines to work for every cluster and concentrating character in the process. Pacific crosswinds sweep across the site regularly, moderating temperatures and extending the growing season in ways the valley floor cannot replicate.

Wente Heritage Clone Chardonnay

Four small blocks of heritage clone Wente Chardonnay were already rooted on this mountain when we arrived. We didn't plant them. We inherited these old vines — and quickly understood why they were here.

The Wente family brought a cutting from Burgundy to the United States in 1912. On a mountain, Wente becomes something else entirely. The harsh conditions — volcanic soils, high altitude, punishing diurnal swings — stress the vine into producing tiny clusters with even tinier berries. Less juice. More of everything else.

The result is white wine for people who thought California Chardonnay was not their thing. High acid. Mineral. Bright. No butter. No oak. If you drink Sancerre, you'll understand this wine immediately. If you don't, this is the one to start with.

The Rhône on the Mountain

One of the first wines the Itkin family fell in love with was Châteauneuf-du-Pape — a wine of place, of complexity, of varieties grown together on sun-drenched, rocky soils. We aren't growing all thirteen Rhône varieties here. Not yet. But we are experimenting with three.

Syrah, Grenache, and Mourvèdre have found a home on Moon Mountain's volcanic slopes — thriving in the same demanding conditions that push every other variety on this property to its fullest expression. It is a beginning. And we are paying very close attention to where it leads.

In the Cellar

Moon Mountain fruit arrives at the Theorem winery with a character distinct from Diamond Mountain — higher acidity, more structural tension, and a wildness that demands careful listening in the cellar. Winemaker Andy Jones, protégé of winemaking consultant Thomas Rivers Brown, approaches each variety from Moon Mountain as its own separate study — single-vineyard, single-varietal, faithful to the mountain that grew it.

Soils: Clay Loam
Planted Acres: 14 across 15 blocks
Varieties: Chardonnay, Sauvignon Blanc, Grenache, Syrah, Mourvèdre, Cabernet Sauvignon
Vines Planted: 2004 — 2023
Elevation: 1,500-1,800 feet

The Moon Mountain District AVA in Sonoma Valley has a track record of producing exceptional wines — we are determined to elevate that reputation further with every vintage. The mountain is still speaking. We are paying close attention.

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