Michael Costley

Winemaker, Signorello Estate

Michael joined the team when the winery opened in 2024. He has been crafting wines in the Napa Valley for the last decade. He will continue to build upon the foundation that was built at Signorello over the past 40 years. With a focus on attention to detail in the vineyard and winery, Michael will help create the purest expression of each block farmed at Signorello to make the best wine each vintage.

Michael’s previous winemaking experiences include Gandona Estate on Pritchard Hill, where he worked with Graeme McDonald and Far Niente in Oakville. The early part of Costley’s career in Napa was as Viticulturist at Merryvale, where he farmed Bordeaux varietals at their hillside St. Helena estate. He holds a B.S. in Enology from California State University, Fresno, and a B.S. in Plant Science from the University of Missouri.

Country born: United States

Education: Certificate in Special Studies in Enology from California State University-Fresno.

Years in the wine industry: 15-20 years

Winemaking Philosophy:
The wine is made in the vineyard. Letting the site and vintage express itself with intention.

Celia Welch

Winemaker, Signorello Estate

Celia brings a vast wealth of talent and knowledge and has been key in the creation of some of Napa Valley’s marquee wines. Celia Welch has been a winemaker for more than 30 years, after earning a B.S. degree in Fermentation Science from the University of California, Davis in 1982.

Her first interaction with grapes was under the huge oak tree in her backyard in Southern Oregon, where she and her siblings picked grape berries from stems for their father, an avid wine collector and home winemaker. Her parents also included the children on trips through Napa and Sonoma in the early 1960s, and, like most visitors, she was entranced with the beauty of the rolling vineyards.

Celia has been honored as Winemaker of the Year 2008 by Food & Wine Magazine, as one of Forbes.com’s “Top Ten Tastemakers of 2006," and with the Women for Winesense Rising Star Award from the Southern California chapter of this group; the national chapter of Women for Winesense inducted her into its Winemaker’s Hall of Fame as well.

Country born: United States

Years in the wine industry: 20-30 years

Steve Matthiasson

Winemaker, Signorello Estate

Steve, a six-time James Beard Award nominee, has advised some of Napa’s most esteemed vineyards, including Araujo, Dalla Valle Vineyards and Spottswoode Estate Vineyard & Winery.

Steve dreamt of farming his entire life. He became an obsessed gardener, cook, and homebrewer while studying philosophy in college. In 1994 Steve began working for a small sustainable agriculture consulting firm overseeeing vineyards and orchards and in 1999 he co-authored the California manual on sustainable vineyard practices.

Country born: United States

Years in the wine industry: 20-30 years