I most certainly am not the first bartender to think of this gesture, but have been doing it for about a decade. In fact, it probably started when the smoking ban went into effect in 2004. A guest would leave a half full beer on the bar to go outside to grab a smoke; all the while, unfortunately their cold beverage gradually began to warm up.
My solution was to turn a Boston shaker into a champagne or wine bucket of sorts to keep it cold. Trust me, this continues today to make everyone smile upon returning to their seat- better than mixology, in good bartending, it's the little thoughtful things that matter, right?
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