The poem is a tiny kitchen scene. Something has been cooking in a pot all afternoon, and the speaker watches it turn into supper. The title, "Reduction," points to the cooking term for simmering a liquid until it thickens and concentrates. But it also hints at the poem's own method: very few words, boiled down to almost nothing.
The strangest image is the last one: "a fresh / string of Xs." Judging by the imagery, the Xs could be the crisscross marks of steam, bubbles, or bits of food floating in the pot, or they could be letters laid out on the page. An X can mean a kiss, a mark crossing something out, or an unknown quantity, and each reading adds a flicker of meaning. Supper becomes both a promise and a puzzle.
The mood is quiet, patient and a little playful. The speaker seems content to wait and look closely at something ordinary, finding a small, odd beauty in it.