The idea for this poem is the parallel between the process of bourbon being made, and the process of it being consumed (and maybe of it consuming us, or at least some of us from time to time). Bourbon gets its flavors from liquor that is pressed by temperature cycles into and out of the charred inner-layer of a wooden barrel. Later at the point of consumption, the same bourbon tastes hot due to it’s high alcohol content; and is sometimes placed on ice. All that ice, heat, warmth, cooling, char, cycling, and so forth, seemed to be a good metaphor for the solitary drinker, remembering while he damages his ability to remember, thinking of past relationships now gone, while at the same time dis-interested in the other human beings right there in the room.
The “memory of flames” was a line that just popped out without any foresight; but it carries the perfect double-implication… the inside of the barrel was charred by flame; and this drinker was himself charred by an old flame of some kind, not described in detail but just remembered in the moment. And remembered only by the drinker, who does not share all his secrets with us.