Extended Metaphor

I Taste a Liquor Never Brewed is a great example of an extended metaphor. Liquor is constantly compared to aspects of nature throughout the poem. The first reference I noticed was an allusion to the Rhine River in line three. Other aspects of nature discussed are air, dew, and the sky (Molten Blue). Many animals and insects are also mentioned. These include a bee, a fox, and butterflies. This reoccurring theme of nature kind of confused me. I'm not sure what the writer's purpose of it was. One theory I considered was that perhaps he was suggesting that drinking was a natural thing to do.