The current cocktail renaissance has caused prices of some historic ingredients to rise sharply but at the same time collectors can still track down vintage bottles that have shown little appreciation in value at auctions. Top bars turn to collectors and traders to track down rare bottles while no home bar is complete without a well-thought-out selection of vintage cocktail ingredients. Isabel Graham-Yooll, Auction Director at Whisky.Auction, advises: Research!The word cocktail emerged in print in...