In Napa’s newest winery, drinking in the medieval air

A castle is rising south of this small resort town that promises to be Napa Valley’s most lavish tourist draw.

Or a vintner’s fortune-busting folly.

In April, Daryl Sattui, whose winery and deli a few miles away in St. Helena are a popular picnic stop, plans to open to the public a sprawling, medieval-style castle and second winery that he has been building for 12 years. At 121,000 square feet, Castello di Amorosa, tucked away on a hilltop off California Highway 29, could hold 50 average-sized homes. It has 107 rooms on seven levels.

But it’s not just big. It’s monumentally eccentric, rivaling the late William Randolph Hearst’s rambling residence five hours down the coast in San Simeon. And like Hearst Castle, it cost a king’s ransom.

Sattui, a self-confessed medieval architecture fanatic who also owns a former monastery and a Medici palace in Italy, figures his current project will eat up $30 million.

“Honestly, I’ve spent everything I have except my pension plan,” said Sattui, 65. “But I don’t care. I just hope I don’t go broke.”

Castello di Amorosa is a meticulous, if not always authentic, vision of a Tuscan castle. It sports a dry moat, drawbridge, iron-gated entrance, five towers with battlements, a church, a great hall, gargoyles and wrought-iron sconces.

More wondrous stuff lies below, in four underground levels.

A dungeon is outfitted with torture equipment, including a reproduction of a rack and an antique iron maiden, which Sattui said he bought for $13,000 in Pienza, Italy. The iron maiden, looking like an upright mummy case, is lined with spikes meant to impale victims shut inside. Near the dungeon is a deep pit designed to hold prisoners.

A labyrinth of cellars, housing thousands of wine bottles and barrels, showcases centuries of architectural elements. The largest underground chamber is the main barrel cellar, 135 feet long, with 40 cross vaults. It contains 1,200 barrels and took three years and $2 million to build, Sattui said.

The most impressive room above is the great hall, which measures 72 by 30 feet, with a 22-foot-high coffered ceiling. Frescoes — decorative but perhaps not museum-worthy — cover the walls, inspired by such classics as Ambrogio Lorenzetti’s “Good and Bad Government,” at the Palazzo Pubblico in Siena, Italy.

Throughout the castle, details attest to Sattui’s passion for vintage buildings. Iron gates, fashioned five years ago, have been aged with acid to appear ancient. Double doors outside the great hall contain 2,000 nails, all handmade in Italy

Swaths of brick cut across rough-hewn stone walls, and doorways appear to have been bricked over, all in an attempt to mimic repairs and alterations to a centuries-old structure.

The project, at first overseen by a Danish naval architect and now by Italian Paulo Ardito, has employed workers from six countries and materials from eight, Sattui said.

Down in Calistoga, known for hot springs and mineral water, Castello di Amorosa is an object of curiosity and some mystery.

“A lot of people don’t know it’s there,” said Kendall Heck, a longtime bartender in town.

When bricklayers gave him a tour, he was impressed with the “fairy-tale thing.” But he added, “It looks like [Sattui’s] got more money than sense.”

Sattui agreed that no rational businessperson would have built his castle. But this son of a San Francisco cabby has beaten the odds before. He borrowed money and lived out of a van while starting up V. Sattui Winery in 1975. Today, it attracts more than 400,000 visitors a year.

“I have a philosophy,” he said. “Average people can do great things if they don’t know they’re average.”

jane.engle@latimes.com