Possible Clues:

• Sour
• You'd gain very little from wine that's so sour
• Acerbic
• Peevish, finding cigarette end in gravy that's lumpy
• Sour tasting
• Sour-tasting wine from France, say, Ray rejected
• Like much Italian dressing
• Acerbic fellow attached to plant
• It can make a gin very bitter
• Like some salad dressing