Chateau Carbonnieux in Pessac Leognan is due to begin picking its Sauvignon Blanc grapes at the end of this week after a 'roller-coaster' season of highs and lows.A cold start to the growing season, and dry weather combined with cool nights in August, have meant that most vineyards are around a week behind schedule.For most properties the white grape harvest will begin next week, with the Sauvignon Blanc at Chateau Margaux on schedule for sometime between September 10 and 20.