This week’s bubbly is from Mumm Napa, a joint venture between G.H. Mumm & Cie, of France, and Joseph E Seagram & Sons.  G.H. Mumm & Cie was founded in 1827, ironically by the von Mumms, German winemakers who trace their ancestry back to medieval times. The Napa location was founded by in 1979 by Guy Deveaux, who…