Seven Things We Learned About Old Californian Vines from Morgan Twain-Peterson MW

Morgan Twain-Peterson, born in 1981 to notable winemaker Joel Peterson, started his winemaking career at age five. The Sangiacomo family of Sonoma gave him some Pinot Noir to play with, which he used to make his own wine. Named Vino Bambino, it was a hit, ending up on several major wine lists.

After university, Twain-Peterson returned to California to work at Ravenswood, his father’s winery, and later went on to work at Hardy’s Tintara in the McLaren Vale, as well as Château Lynch-Bages in Bordeaux. In 2007, he founded Bedrock Wine Co., in what had once been a chicken coop, on the outskirts of Sonoma.

His first fruit came from family vineyards, including Bedrock Vineyard, planted between 1888 and 1895; Twain-Peterson has since added other, significant vineyards to the Bedrock portfolio. Many of these vineyards boast vines that were planted before 1935 — altogether, Twain-Peterson can call on more than 22 grapes varieties, including now-obscure ones like Peloursin. The majority of grapes in the Bedrock Vineyard, however, are Zinfandel.

Almost uniquely, Bedrock Wine specialises in old vine wines, with Twain-Peterson making what he calls “heirloom wines”. He is keenly interested in the old technique of field blends and believes that the trend from the 1980s onwards of making grapes like Zinfandel into single varietal wines did them a great disservice.

Twain-Peterson, who became an MW in 2017, also founded the Historic Vineyard Society alongside other winemakers such as Tegan Passalacqua of Turley Wine Cellars.

He joined Areni Live in California in June 2023, to discuss old vines.

Where do California’s vines come from?

Twain-Peterson says the first Vitis vines entered California in the 1860s, thanks to Haraszthy Ágoston, often called “the father of American wine”. “He’s widely credited with bringing in Zinfandel,”— which he didn’t — “but he brought in a lot of other really interesting things.”

Unfortunately, there was no government body at the time to catalogue the varieties, so local regions would have their own name for a grape, making it hard to trace which grapes came from where. “It’s like Tempranillo in Spain — everybody has their own regional names for things.”

In 1873, Phylloxera appeared in Sonoma, and by the 1880s was spreading rapidly through California. To try and stem the devastation, California created the  Board of State Viticultural Commissioners, who “went to Europe and collected as many different varieties as they could.” Its chief viticultural officer, Charles Wetmore, worked with growers to trial more than 2,000 varieties.

“He had Trousseau, Grenache, Tannat, Malbec,” says Twain-Peterson. “They’re looking at all these major varieties on top of a lot of minor varieties, and they’re trialling all of them.” He says the importance of this can’t be overstated, because, “in the 1880s, it was estimated that 80% of vineyards in California were planted to Mission, the original variety that came over and did not make particularly great wines.” But by 1888, plantings of other varieties had gone from 30,000 acres to 150,000 acres across the state of California.” 

Throughout the 1880s there was experimentation with all these varieties, and with different root stocks. “The first documentation of successful grafting under Rupestris  St. George, which is what the majorities of these vineyards are planted on, was in 1885,” says Twain-Peterson. “So if you ever hear of people claiming a vineyard was planted before 1885, and it’s not on rootstock, it’s just not feasible.”

The result of all this work is that, “Sonoma Valley has four of the very first vineyards replanted under resistant root stock.”

Are old vines just a marketing tool?

Twain-Peterson says not only are old vines not a marketing tool, but they used to be a liability.

“I think for many years, just because California is a relatively young industry, it’s always been about what’s new and what’s exciting and all the drive that goes into modern California wines,” he says. “All of that has been good, but I think that in some ways a lot has been done at the cost of ignoring a deeper history that actually existed here.”

“For many years, just because California is a relatively young industry, it’s always been about what’s new and what’s exciting and all the drive that goes into modern California wines. All of that has been good, but I think that in some ways a lot has been done at the cost of ignoring a deeper history that actually existed here.”

Morgan Twain-Peterson MW

Do old vines make better wines?

Twain-Peterson is clear that just because vines are old doesn’t mean they’re good — but that a vine that has survived for a long time probably did so for a reason. “My general feeling is that if you have a vineyard that has survived Prohibition, two World Wars evolving consumer tastes, the onslaught of housing, Cabernet, Pinot Noir, et cetera, it’s still in the ground, that’s a pretty good indication of Darwinian survival.” In other words, there’s a good chance they are excellent vines.

“My general feeling is that if you have a vineyard that has survived Prohibition, two World Wars evolving consumer tastes, the onslaught of housing, Cabernet, Pinot Noir, et cetera, it’s still in the ground, that’s a pretty good indication of Darwinian survival.”

Morgan Twain-Peterson MW

How do you farm old vines?

“One of the lessons that we’ve really learned when it comes to how we’re developing vineyards now is that all of these vineyards were originally developed without irrigation, so they had to be done on a wider spacing,” says Twain-Peterson, adding that the row spacing was often determined by what other agricultural activities were going on. “Out here in Geyserville, most people had orchards,” which meant that  vines were “all on 12 foot spacing — so basically they would be able to work the vineyards with the same double team of horses that they were using in their orchards”

Twain-Peterson says that most old vineyards in California are on a square spacing, “eight by eight or 10 by 10, which allowed cross cultivation. You could just get rid of the weeds if you cross cultivated. And some are on a diamond pattern so you could actually till three ways — three times the devastation.”

Viticulturist looking at old Californian vines
Looking at old vines in Nervo vineyard, Sonoma, June 2023

Altitude changes things

“Our highest vineyards are probably up in Amador County up in the foothills up at about 1,600 to 2,000 feet. And we have actually one Zinfandel vineyard on the very top of Mount Veeder at 2,100 feet, which is a fascinating expression.”

The sea interacts with the elevation to change the terroir markedly. Vineyards on the valley floor, for example, will be under a layer of fog. “It’ll be much colder at night and it’ll be higher humidity. And then if you’re high enough up on the hill, you’ll be above the fog layer and you’ll have the inversion layer, which is also keeping the fog layer down. So it really can actually create a very different wine and very different growing conditions, even from vineyards that might be two miles apart as the bird flies.”

The biggest challenge with old vines

“I think probably the biggest challenge is the fact that there’s still a perception of a price ceiling on these wines,” says Twain-Peterson, despite the widespread discussion about value of old vines. “If we were to go out and price every single one of these wines at a hundred dollars a bottle, I think we would be out of business because I just don’t think there would be enough demand for them. And we do it, we sell about 80% of our wines direct to consumer mailing list, so we get better margins that way. But even then it’s like we’re selling it for $45, $48, $50 a bottle.”

“It’s just consumer understanding. I feel like it has been changing, but it changes slowly. I feel like we really have done incredible progress and we have great feedback. We have very loyal customers that buy our wines. But it is tricky because our Bedrock Heritage Wine has been in the Wine Spectator Top 15 three times. It’s received 95 plus points from every major critic in the world. It’s like it has everything attached to it that you would normally expect of something that would be a high price-point wine, but there still is a strong inertia that we’re pushing against. “

Twain-Peterson says the company has “an incredible vineyard in Lodi. It’s planted in 1915. It’s own rooted. It’s remarkable. But the reality is that if we were to price that the same as we price Oakville Farmhouse or Bedrock Heritage, there would be people would look askance at it. We wouldn’t really be able to sell it because of the appellation.”

“Our Bedrock Heritage Wine has been in the Wine Spectator Top 15 three times. It’s received 95 plus points from every major critic in the world. It’s like it has everything attached to it that you would normally expect of something that would be a high price-point wine, but there still is a strong inertia that we’re pushing against.”

Morgan Twain-Peterson MW

Perceptions of Zinfandel

“I think right now Zinfandel is really challenged because anything that’s perceived to be over like 12.5% alcohol is somehow perceived to have not past the litmus test. And that’s also challenging. It means that a lot of younger people that are getting into wine making and are energized by the concept of natural wine are also shying away from Zinfandel in some way, which is also a bit of a challenge because Zinfandel, as it ripens, it’s quite hard to make it at under 12.5% alcohol. “

This conversation has been taken from a wide-ranging discussion that involved multiple people. It has been edited for length and clarity.


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