Sandi Belcher is a native of Williamsburg, Virginia, where she grew up in a loving Greek family. She graduated from the College of William and Mary and then pursued graduate work at the University of California, Davis. She studied Animal Science/Agriculture there, convinced that her future was in caring for large animals or at least large agricultural crops.

Ultimately, however, wine totally won her over. She completed a degree in chemistry and agriculture in 1974 and, in the course of her studies, also worked at Chateau Montelena, Heitz Cellars, and the UC Davis vineyard experimental station in Oakville. In Oakville, Sandi made wine with fruit from vines she had helped trellis using a number of different methods, and at Heitz she helped with its now-legendary Martha's Vineyard 1974 Cabernet Sauvignon.

After graduation, Sandi traveled around the world, working in a number of wineries before returning to the U.S. in 1978. Upon her return, she was hired as winemaker by Long Vineyards on Pritchard Hill in St. Helena, where she worked alongside Bob Long, with Zelma Long consulting. During her time there, Long Vineyards grew from 800 to 2,000 cases and from a production of only Chardonnay to Cabernet Sauvignon, Chardonnay, Pinot Grigio, Riesling, and Sauvignon Blanc. Sandi was winemaker at Long until the property was put up for sale in 2005.

In the early 1980s, Sandi teamed with her partner, John Arns, to fulfill their mutual desire to make Arns Winery what it is today. Their focus is on making Cabernet Sauvignon and Syrah.

Sandi also has been involved in vineyards and winery development in China, Thailand, and other grape-growing regions. Her daughter, Kathi Belcher/Tyler, is Assistant Winemaker at Arns. She routinely works with Sandi at harvest and at bottling and can be relied on at a distance to take care of things in the winery when Sandi is out of the country.