Of Sonoma County's 20,000 acres under vines, about 9,000 are planted to Zinfandels, 3,000 to Petite Sirahas, and 2,000 to Carignanes. These, of course, are not varieties likely to produce a Chambertin or a chateau Latour. What they can and do produce, in gratifying abundance, is something that we can all afford to drink, and drink with enjoyment, at our daily dinner table.