There are fewer than 200 Master Sommeliers in the United States. Of these, fewer than a half-dozen live and work in Los Angeles, and only one, Spago's Christopher Miller, is currently working on a restaurant floor. Miller, one of six recent conferees, has been instantly vaulted to the front of a very distinguished pack. Miller studied for the M.S. exam during the frenetic days leading to Spago's summer shutdown, asking the staff to pop random questions at him, reciting the appellations of Portugal under his breath while he waited at the bar to fill a Champagne order. Since 2007, Miller has expanded Spago's wine holdings dramatically, from 400 selections to more than 3,000, recasting an already strong list into a marvel of variety. It remains a bastion of great California wine, but it has become a powerhouse for Bordeaux, Burgundy, Champagne and, especially, riesling. ("I'm going to make this the best selection of riesling in the country if it kills me," he says.) Some of this expansion came during the recession years: While wineries and distributors were shedding inventories, Miller was stockpiling, knowing that such offers might never come again. The cellar is deep, like an arsenal, for Miller's ongoing tenure at L.A.'s flagship restaurant. 176 N. Canon Drive, Beverly Hills. (310) 385-0880, wolfgangpuck.com.