Coteaux du Giennois is not as famous as Sancerre or Pouilly-Fumé, the two great Sauvignon Blanc-producing appellations of the Loire Valley but it often offers better value for money, partly because of its lower profile. This one from Vignobles Berthier, sold under Sainsbury’s reliable Taste The Difference label is tangy, stony and refreshing with a lovely interplay between citrus and passion fruit flavours.