RICHARD EHRLICH turns his attention to the role of the mixer this week and comments: 'You can't make a good cocktail unless every single ingredient is high quality.' One possibility with vodka is Grove Fresh Original Tomato and Vegetable juice (2.39-2.79; selected Tesco, Waitrose, Sainsbury's, Booth's and independents), which is described as 'all organic, improbably good for you, and entirely delicious'.