Clue: King that is wanting alcoholic drink, a type of wine (8)
Answer: RIESLING
Explanation: Definition: a type of wine
 R(abbrev. for "Rex"/King) + IE(abbrev. for "id est"/that is) **plus**(wanting) SLING(an alcoholic drink, viz. a cocktail of spirits with water and sweetened).
Defn: …, viz. a dry white wine from a grape variety grown in Germany, Austria and elsewhere.